Into the Impossible With Brian Keating - Astronomy’s Great Debate – The Nature of the Universe and the Future of Astronomy! (#091)

Episode Date: November 13, 2020

Host of Into The Impossible Professor Brian Keating, David Spergel, Janna Levin, Sara Seager, Wendy Freedman, & Nobel Prize winner Adam Riess debate the hottest topics in modern astronomy while celebrating the Hubble Space Telescope’s 30th birthday! An all-star (get it??) party featuring observations of Hubble’s ‘greatest hits’, courtesy of Wyoming Stargazing Association! Plus we debated the greatest mysteries in the Universe including: What is the nature of Dark Matter? How did the Universe begin? How will it end? Is there life beyond earth? What is the nature of Dark Matter and Dark Energy? What is causing the Hubble Tension and how will it be resolved? Brian Keating’s most popular Youtube Videos: Eric Weinstein: https://youtu.be/YjsPb3kBGnk?sub_confirmation=1 Jim Simons: https://youtu.be/6fr8XOtbPqM?sub_confirmation=1 Noam Chomsky: https://youtu.be/Iaz6JIxDh6Y?sub_confirmation=1 Sabine Hossenfelder: https://youtu.be/V6dMM2-X6nk?sub_confirmation=1 Sarah Scoles: https://youtu.be/apVKobWigMw Stephen Wolfram: https://youtu.be/nSAemRxzmXM Host Brian Keating: ‍♂️ Twitter at https://twitter.com/DrBrianKeating Instagram at https://instagram.com/DrBrianKeating Buy my book LOSING THE NOBEL PRIZE: http://amzn.to/2sa5UpA Subscribe for more great content https://www.youtube.com/DrBrianKeating?sub_confirmation=1 ✍️Detailed Blog posts here: https://briankeating.com/blog.php Join my mailing list: http://briankeating.com/mailing_list.php Join my Facebook Group: https://facebook.com/losingthenobelprize ️Please subscribe, rate, and review the  Learn more about your ad choices. Visit megaphone.fm/adchoices

Any sufficiently advanced technology is indistinguishable for magic. Welcome everybody. Very thrilled to have so many phenomenal guests joining us. Today we have David Spargo, Wendy Friedman, Adam Reese, Jan 11, Sarah Seeger, and myself. Plus, we have Sam Singer and Michael Adler from Wyoming Stargazing Association. So we are really thrilled to have everybody here joining us. We have a lot of people viewing already. And I want to thank all my guests and thank the audience.

And tonight's going to be really fun. It's sort of experimental art. And we're going to do our best to make it through. I'm going to send out the actual link to everybody on YouTube. And then we'll get started with some introductions. So, as I said, places everybody. And we're going to get started. And if you have a moment, there was a link to register for the giveaways that will be going on after the live stream ends.

We're going to have many, many giveaways of phenomenal signed artifacts from our phenomenal guest. So please do visit the link that I'll put in the chat box. in just a second. So let me pin that. Okay, we now have count them over 51 people viewing, but that's going to go up. So I want to welcome everybody to the live stream. I want to introduce my friends who have joined me today in this project that sort of conceived a few months ago when I recognized that we were in the 100th

anniversary of the so-called Great Debate, which is the famous Curtis Shapley debate, which solved a little thing or helped us solve a little thing called the size of the universe. So we're joined today. We were going to do some live stargazing. Unfortunately, because of the weather in Wyoming, who would have guessed that in South Central Wyoming in November, there'd be bad weather. But nevertheless, there are usually great opportunities for stargazing, and I want to point your attention to Sam Singer. I'll now highlight him, and he can introduce himself and describe. and describe the mission of the Wyoming Stargazing Association.

And then we'll show us some images of their facilities. Samuel, welcome to the live stream. Great debate. Thanks so much, Brian. Thanks for having me. Wyoming Stargazing is a 501c3 nonprofit organization based in Jackson, Wyoming, as Brian said. And our mission is to inspire and educate through Wyoming's extraordinary skies. We do that through in-person stargazing program.

and more recently virtual stargazing programs, as well as lots of other indoor presentations. So as Brian said, we do have a snowstorm tonight. We've got some great images that we've taken over the past couple of months that we're going to share with you as well as some cool process, color images done by one of our board members, Mike Adler, who is also here with us tonight.

Yes, and that brings me to a description. I'm going to share my slides here. So first of all, I have the panel that I'm going to show up here. And there's the two of us. Let me share my screen. I'm going to share the keynote that we prepared with some images that we're going to be talking over today. So can everybody see that on anybody watching on YouTube? Let us know about that.

And by the way, we are monitoring the comments. So please provide live chat comments, et cetera. So this we're calling the Great Debate Version 2.0 and welcome everybody. So the great debate took place in this facility, which is the Smithsonian Institution in Washington, D.C., which looks little different than it did over 100 years ago when this great debate took place in April 1920. Just to set the scene, it was right after World War II had ended. It's right after the Spanish flu had sort of claimed. World War I. Say that again?

World War I. World War I, sorry, yes. It was unfortunately a precursor to World War II. You see here the headlines of the New York Times. And you also note that the Spanish flu had just barely come to an end, only a few months earlier prior to the great debate. And you may wonder, well, what was this great debate about? It wasn't a presidential election, although there were many, many hotly contested

election contestants at that time. Warren Harding, the eventual victor and his vice president, Calvin Coolidge. I like to point out that the administration lasted, you know, little more than some TV sessions last. And that was only about 18 months or so. And so Warren Harding never got to hear the outcome of the great debate, which was settled only about three years after the actual great debate took place. It wasn't settled until 1923. Brian, I'm not sure if your slides are advancing. Oh, they're not, huh?

Okay. Let's see here. Let me see. Bring your sharing is paused. Bring your screen to the front. Stop share. All right. What about now? Can you see some? Okay, good. So this is the remembrance of the events I talked about, Germany surrendering, end of World War I, Warren Harding, running with Calvin Coolidge, with a song written by Al Jolson. That's pretty funny. And then they ran against James Cox and Franklin D. Roosevelt, who I believe did have a successful campaign many years later. And then this great debate was held, and I think it really inspires us as astronomers, that this is really the enduring takeaway from 1920 was that this great debate kind of persists

in our memory, and whoever was running for vice president really is lost in history, at least unless you're Nate Silver or somebody like that. So you see the two, gentlemen that we're going to be kind of talking about Hebrew Curtis and Harlow Shapley. And we're going to be talking a lot about the telescopes that they use and future telescopes built in some cases by people that are on this very live stream. This is the Hooker Telescope in Mount Wilson. And it really harkens back to where do we sit in the universe? And to begin, I want to sort of start with the man that really settled this was Edwin Hubble, but he couldn't really settle whether or not these smudges, these nebulae, were actually in the Milky Way or outside of the Milky Way.

This is M51. I think we'll see an image of that from Mike Adler's instruments in just a bit. Here are some sketches. Herschel observed these. And of course, it wasn't until Henrietta Swan Levitt took images of the sepheids that we began to discover what it meant to measure distances out beyond the Milky Way galaxy. And of course, I'd be remiss if I tried to explain these data. And I wanted to maybe first start off with Wendy Friedman, who has been known to use a sephiate or two in her day, to talk about what did Henrietta Swan Levitt do? And why was it

so important to discover these mysterious objects called sepheid variables? So you're going to go back to Henrietta? Yeah, that's her, I believe. Yeah. So in 1908, Henriette Leavitt, who was working at the Harvard College Observatory, discovered as she was looking at one of the nebulae, the large Magellanic cloud, two of them, the small Magellanic cloud. And she found that there were stars in the nebula. And when she measured how bright those stars were as a function of time, she noticed that the luminosities of the stars changed. They got dim for a while, then they got brighter, then they got dimmer, and they did it in a very characteristic way.

And there had been a type of star known as a sepheid. It had been known for a couple centuries before that from our own galaxy. and she realized that the brightness of the sephid stars that she had found had a one-to-one correlation with how fast they changed in their brightness. So here is her what is now called the period luminosity relation. And actually recently, it's been named the Levitt law in recognition of her discovery. So the bottom axis shows the logarithm of the period of variation. These stars tend to vary on timescales of a couple days up to maybe 100 or even greater than 100 days.

And then on the y-axis, the luminosity is increasing as you go up. And she's looking at the maximum luminosity of the stars on the top here and the minimum luminosity. Today we tend to look at the average luminosity. But the uniqueness of these stars, the power of these stars is that once you realize there is this correlation, if you can measure the absolute or intrinsic luminosity of a sepheid in, say, our Milky Way galaxy, so it's power, it's wattage, then you can measure the sephiads in a nebula, and you can see, is this nebula nearby, or is it far away. And so maybe we'll talk about this a little bit more later. You can use geometric parallax, for example, to set the scale in our Milky Way galaxy, and we're getting ahead because Henrietta Leavitt

wasn't able to do that. But the power of her discovery is that you go find these stars. They're changing their brightness with time. You measure their periods. You get a sample them in a galaxy. Then you compare them to ones in our own galaxy for which you know the distances. And then just as you look at a lamp post in the distance, we know that things get fainter as they get farther away and they do that in a precise way, falls off as the square of the distance from us. But sepheriaes remain one of the most accurate and powerful ways that astronomers have today to measure the distances to galaxies.

And that's what Edwin Hubble did. He found these sephiates in a few galaxies. and now we know is our local group nearby galaxies, including the Andromeda galaxy. And he was able to show that these stars in these nebula, based on the Cepheid variables, were much farther than our own galaxy. So they weren't actually regions of star formation

in the galaxy, which was part of the debate in the Shapley-Curdis debate. So we use them today. That was one of the main goals of the Hubble Space Telescope. was to be able to accurately use sepheids to measure the distance scale of universe, which I'm sure we'll get into more later on in the discussion. Yeah, thank you very much.

I love the way that in old days, you know, people could make plots and not label the axes or label the axes incorrectly. So here's a law that's the law. So here is Hubble's famous diagram. I mean, Adam, David, you guys can chime in here. If one of your students turned in a plot like this with incorrect units with no error bars, what kind of grade would she expect to give? She'd get it right.

He got it wrong. Brian, I wish that that was only errors that people made in plots back then. I can show you some papers from some of our colleagues, some famous ones. Oh. I don't know. I hope I look past the wrong labels and see the profoundness of the result. Yeah. So, Adam, let's go back to that time. I mean, you're a little older than I am, but not that old. And when Hubble discovered this famous Seffiate in the outskirts, I believe it's on this side here, if you can see my screen, he immediately crossed off the sign that he had made for a Nova and replaced it with Vair. Why is this so important? to get one single star. And actually, I've never known. How did he know this was not a foreground star?

I mean, what gave him the confidence? Well, that's a great, those are all good questions. So people knew about what we would call novi or even supernovae, which are, you know, they're sort of one-time deals. You know, they get bright, they get faint, that's it. So Hubble was observing this star, thinking initially that it may be a nova or variable, but he saw it start to repeat. And so he crossed that off and realized, oh, this is a variable star, not one of these novi.

And then he could, as Wendy described, associate that with more nearby versions, compare their brightnesses and determine that the Milky Way was, sorry, that Andromeda truly was far away. Then to determine, as you said, you know, how do you know it was an Andromeda? You know, he looked off the field. He looked away and noticed that he was seeing lots of these Cepheid variables superimposed on Andromeda and not away from Andromeda. And so he realized, okay, these are certainly in Andromeda. And then at the center of these massive, beautiful spiral nebula, as they used to be known, and many of them have a heart of darkness, a black hole.

And today we're joined with Jana Levin, who was to be congratulated on the publication day of her fourth book entitled Black Hole Survival Guide. Now, Jana, if we take a journey to the center of Andromeda, that. Will we be safe from a black hole or will we possibly meet a type of doom that none of us can imagine known as spaghettiification? Well, there's definitely a black hole, supermassive black hole at the center of Indromeda. It's bigger than ours. And we're on a collision course with Indromeda, which is interesting. There's sort of a competition between whether our star will descend and die or will collide with Indromeda. We'll probably collide. I don't know, somebody remind me which one

happens first, but we're definitely on this beautiful collision course with Andromeda. And so the expectation is that the entire solar system will stay intact as this happens. They'll pass through each other because the stars are actually quite sparse. So they'll pass through each other and then they'll come back and they'll do it a few times before eventually they coalesce and our black holes merge. And our whole solar system hopefully will stay intact and just be on some peculiar orbit around this new supermassive black hole. This episode is brought to you by Netflix. Most valuable promotions in Netflix are hosting a blockbuster triple headliner Saturday, May 16th.

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I've actually had the actual plate in my sweaty hands. They don't let you do that anymore, but I knew one of the archivist. And you can almost feel the palpable. It was a director. We still did that. You did that, right. Okay. Well, I didn't drop it, Wendy.

Don't worry. Now, Wendy, when you see these things. like these light curve that's superimposed here. This is called V1 in Andromeda. So there's a sepheid there. It looks pretty good, but I mean, could you, you know, can you say something about the challenges of modern day extrapolation? It seems like Henrietta Swan Levin was heroic, as was Hubble in a certain sense, entrusting the data, you know, to really make this far-flung association that these objects are at great distances, and then later that they're receding at great velocities. And we'll get into that in the moment. But how well,

do we know the actual, how much has the improvement has there been in both sephiads and other distance ladder techniques? Yeah. So if you look at these data and you think, you know, here are sephiads, which are faint against the background of Andromeda, right? So it's hard to make these measurements very accurately because what you're trying to do is measure a single star, how bright it is, But you have to contend with the fact that it's in the disk of the galaxy. And then when you think back to what Hubble and Levitt were dealing with, at that time, the detectors that we had were photographic plates. They weren't electronic detectors, the charge coupled devices that we have today that we all have in our cell phones,

similar technology. But they were emulsions on a glass plate, so this original of Hubble. and photographic plates were very inefficient. Only 1% of the light coming from the distant galaxies lands on your photographic emulsion. But worse than that, there wasn't a one-to-one correspondence between the brightness and what you measured on your photographic plate. So they had a lot of issues to contend with, including the fact that they weren't able to correct for the presence of interstellar dust. So that's dust that's expelled from the atmospheres of stars. It absorbs the light that's coming from your sepheids and it scatters it.

So it makes it look fainter. And then you have the Earth's atmosphere to contend with, which is why the Hubble Space Telescope made such a big difference. So yes, these measurements were very, very difficult. And in fact, Hubble got it wrong by about a factor of seven. The original value for the Hubble constant that he measured, so the Hubble constant being the slope of the relation that you showed, I don't know if you want to go back to that, between velocity and distance. And so I'm not sure we pointed out to viewers who weren't familiar with this plot before, but what we were referring to what Hubble got wrong is that the units of velocity

he put in kilometers rather than kilometers per second. And so you can see there's a lot of scatter in this plot. It's quite amazing that the implications of this result. So what he found is that the greater the velocity of a galaxy, the farther away the galaxy is. And so you could see there's quite a bit of scatter along that line, and that's because it was hard to measure the distances. But there's no question that there is a correlation, and the implications of that correlation were enormous. It's what eventually what we came to realize implied, if you took it together with Einstein's general theory of relativity that he had developed in 1915, if a galaxy is far away, it's moving faster from us or appears to be moving faster from us,

and that would imply that there was a time in the past when galaxies, in fact, all met her, was closer together, denser, hotter, and what eventually led to our picture of a Big Bang universe. So the implications of these results were enormous, even though he got it wrong by about a factor of And David, you pointed out in publications of the National Academy of Sciences over two decades ago that, you know, one of the reasons was that the reddening of dust, combined with the lack of sensitivity of the photographic emulsions, made for this, as one of our former presidents used to say, misunderestimation of the actual value of the Hubble constant. Can you say something about what was the actual resolution that caused Hubble to get it wrong by a factor of

seven, again, I'm not that great an astronomer, but I'd like to think I could get, you know, close to an order of magnitude. Why did he get it wrong by so much? And why should we have any confidence in these astronomers who are so graciously joining us today, that they now know what they're doing to the sub-percent level? Well, you know, I think it's actually, before I get to that, I wanted to actually step back and look at what we're wrong with Shappley, right? Because this was the great debate. Yeah. And Shappley had this argument that, and draw when it was right near us. And Shappley's arguments were actually pretty good, right?

I sometimes think we look at the losers in these debates, or we look at, you know, Hubble and say, how could they get that wrong? But these are really good scientists. Yeah. And sometimes one has an incomplete picture and you're drawn to wrong conclusions. So one of the things he saw,

and this ties into something we'll, I think, touch on later, is he saw this, there was the observation of this explosion as Andromeda in the center. And it was so bright, so 10,000 times brighter than, if you assumed Andromeda was far away, it would be 10,000 times brighter than the novae we saw in our galaxy. It was one of two possibilities. He assumed the simplest one. It was like other objects. We saw an Andromeda was close.

We later learned it wasn't a novi. It was a supernovae. A whole different class of objects, one that Adam and others studied in detail, and that this new kind of explosion, the reason it was so bright was that it was just something they'd never seen before. And the second mistake was an observational error

made by a very capable astronomer named Von Manning. who thought he had measured the rotation of Andromeda, that the whole image that you see behind me, behind you on the screen, was rotating pretty rapidly, and that they thought they had seen some of the stars, those spots, which we now know to not a lot of these bright things are actually star-forming regions, in this image here, were appeared to be rotating. And I think a lesson from the debate was people, many people felt that, well, Curtis ended up being right.

It was Shappley, who had the best arguments and won the debate. And as you noted, it was only later when Hubble's data came in on Cepheid's, where things clarified. And so, yeah, I want to turn to the Hubble Space Telescope, but before we do, we should talk about Hubble himself. the telescope's namesake, who was reputed to have wanted to have become a lawyer and actually went to Oxford, I believe, to become a lawyer. And he actually went through with it because his dad really wanted him desperately to be practiced law. And then his dad died, I think, in 1913. And he's reputed to say, upon quitting the law profession, and I know there's many lawyers listening out there, but he's reputed to say, I'd rather be a second-rate astronomer than a first-rate lawyer.

He certainly turned out to be a first-rate astronomer, and I'm only sort of teasing. It's funny that he didn't practice law, but he has a law named after him, and he has a telescope named after him as well, and I want to talk about that with Adam. There's a picture of it sitting behind Wendy, and I'm going to put that also on my presentation now. Adam, can you talk about the work that you do with the Hubble Space Telescope? And then I want to talk about the test instrument that Sarah led, as well as telescopes in space, get above the atmosphere. Why is that so important if we're still discussing Hubble's data taken from

ground zero, you know, from outside of Los Angeles, I always point out, pre-smog. Why is it so important to get above the Earth's atmosphere? Sure. Well, if you've ever sat in a swimming pool and looked out at, you know, somebody, you notice it's very difficult to see them well to count how many fingers they're holding up something like that. And that's the problem we have down on the ground. When we use telescopes, We're sitting beneath an ocean of air above us that blurs the images. When two points of light that are close together come to us, they can often merge as they pass through our atmosphere. And so we don't get these very sharp images that we need. And as was described, in order to figure out how far away galaxies are, we need to resolve or recognize individual stars in those galaxies, which is very difficult to do from the ground.

Now, in the case of Andromeda, it happens to be the nearest galaxy. And so that gives you a better chance to resolve individual stars. But as we find ourselves wanting to measure much greater distances, we need to be able to resolve individual stars in much more distant galaxies. So like looking at your friend who's holding up three fingers while you're under the pool and your friend's very far away. It gets harder and harder. So there was a clever idea in 1940s, not realized until. around 1990 to launch a telescope up into space sitting above this ocean of air to get the pristine kind of resolution you can get from a telescope when the light is not blurred from the atmosphere.

And so with this telescope, it is possible to pick out these individual Cepheid variables that Wendy described, but much further away. I would say maybe 40 or 50 times further away than Hubble did from the ground. And if we can look at it. look out further and measure greater distances, we can reach out to some of these galaxies that also hosted one of these exploding stars that David mentioned appeared in Andromeda in 1885, a supernova. Now, a Cepheid variable is a very luminous star. It's a super giant star. It's 100,000 times as luminous as our sun. And so we can see them very far away. But a supernova can be as bright is 5 to 10 billion times the luminosity of the sun.

And so if we use geometric parallax to figure out how luminous a sepheus a sepheid is, we can then observe a sepheid in a galaxy that hosted a type 1a supernova and figure out how luminous the supernova is. And then we can see lots of supernovae well out into the expanding universe and use that to calibrate how fast the universe is expanding today. Now, getting a telescope into space is no mean feat. And there's one of us, at least here, Sarah Seeger, professor at MIT, author of one of the books we're giving away. So I want to remind people in the comments, I've got a link to sign up so you can be eligible to win both books by Professor Sarah Seeger, Professor Jan 11, her newest book, signed copies.

Some guy named Brian Keating has a book that you can get as well, plus signed papers by Wendy Friedman. on the key project done by the Hubble Space Telescope, which we'll get back to in a bit. And also by none other than Adam Reese, the paper that brought home some Swedish gold, it's not showing up super well. Anyway, sign up in the link. I'll put another link to it.

Sarah, what's it like before a telescope launches on a SpaceX rocket? Talk us through the emotions that you feel and then what the mission was about. Well, first of all, it's always a blast. It's always fun to go down to floor. And what's so great about the mission when you're waiting for it to launch is you see all of your friends and colleagues, some you haven't seen for many years at the hotel, at the beach. Everyone's waiting for that really special launch day. We, for the test mission, and typically if you're on the formal launch party, you go in a bus at NASA and drive to a site on NASA property. And just as the bus was pulling in, we get an announcement.

We're turning back now. it's not not going to launch at the moment. So then you wait because the team has to figure out what went wrong, why isn't it launching? Yes, and so we had a couple of extra days in Florida. And then you go to the launch and it's amazing, but the whole mission, everything you've worked on for so long, and I wasn't working on tests as long as some other people,

but it's all up there in that tiny top of that ferrying and kind of top of that rocket in the ferrying and you're just kind of keeping your fingers crossed. But I wasn't so nervous because you're just sort of caught up and watching the rocket, watching it launch, listening to the loudspeaker, the countdown, everything. And then it goes in the sky. And it's just one of the most beautiful, like incredible things ever. I hope you all get to see a launch. You know, when we get back to travel normal, new normal, anyone, you can see a launch.

You have to pay like $50 or something. But anything that happens to be launching when you're there, you can do the official launch. But you don't even need to do that. Sometimes there's a better view along the road or at the beach actually. So that was the mission. And it's not just, that's not the nerve-wracking part, but once you turn everything on, you know,

you want to sure it actually works properly. And yeah, it turns out there's sort of this huge history that pretty much everything that you turn on has some kind of problem. But no one tells you, it's sort of hush-hush and secret. So there's no like lessons learned list you can go to.

But as Adam and others were saying, you know, above the blurring effects of Earth's atmosphere, it's just incredible. And the test mission and, you know, Kepler before it can do incredibly precise photometry, brightness measurements as a function of time. But tests, too, it's not just that on Earth that's bad for us, for astronomy, for exoplanets. It's the day night we have here on Earth. You know, like, I'm sure you love daytime, right?

Brian, you want to wake up and have day and you want to go to sleep and have night. But that's bad for exoplanets because the transits get chopped up. It ruins your so-called visibility. function of trying to find periodic events. So Tess is in a really brand new unique orbit. It orbits Earth in resonance with the moon. It has a two-week orbit about and it goes out to half the distance to the moon. And then it comes back and it keeps orbiting. It's just so that when test is at its furthest point from Earth, the moon is on one side. And when test goes back to that for this point, the moon is exactly on the opposite side. And the moon is actually stabilizing the orbit, allowing test to

look at like a continuous night sky for nearly two weeks at a time. So yeah, the test mission is amazing. I just want to say one more thing. Yeah. I thought you were going to ask me, what is it like to find planets? So I'm about to do that. Really, it's the most amazing thing ever to find a new planet. And it kind of is, and I hate to kind of say this out loud, but like any job, it gets a little tedious, let's say. Like, it's crazy to say that. But, you know, it's sort of over and over again, same, same, same, same, same. And every month, though, it's pretty amazing that the test mission finds about 100 new planet candidates. So not actual planets, but 100 new potential worlds.

It's quite a mission. And one of the ways you do it, I'm showing on the screen now, I think it should be visible, is through eclipse of planets that have atmospheres. And of course, you and your team made some news barely in the last month with an announcement of evidence for the production of phosphine in the planet Venus's atmosphere.

And I wonder if you can comment a little bit on that, just first describe what the discovery was and what the current status is. I understand there is a little controversy surrounding it currently. Sure, sure. Okay, so we've switched topics completely now. Yes, yes. I know. We don't have too much time with you guys. I want to make sure I did.

All right. So we switch topics. We're going to drop exoplanets now. And just let's say, just for a bit of background, one of my main research areas is thinking about what kind of gases could we find on exoplanets in the future when we can study small, rocky planet atmospheres. And one of the gases my team came across was phosphine. It sounds incredibly obscure. It's associated with life on Earth in oxygen-free environments. And it's not made any other way on this planet, except for us humans make it and bacteria almost certainly make it. So while my team had worked on this and put out a few papers, across the pond out in the UK,

Professor Jane Greaves independently had realized that phosphine is a good biosignature gas. And she had purposely set out to look for phosphine on Venus, and hence, mutual contact connected our two teams. And we chipped in to help Professor Jane Greaves with analysis, with an interpretation of what she found. So the team announced the detection of phosphine on Venus a couple months ago, and it was based on two different telescopes. It's a radio telescope.

It's the James Clerk Maxwell telescope in Hawaii and the Alma Observatory in Chile. Now, we saw the same feature in two different telescopes. but Venus being very bright and spatially resolved. By the way, would you ever point Hubble at Venus? Adam, Wendy, would you? Yeah, see. It's too bright. It's so bright.

Okay, see, I made them laugh, but it's hard to observe really bright things. It sounds ironic, doesn't it? Like, wow, I mean, if we, yeah, I mean, it's hard to observe bright things, and it's hard to look for tiny signals. And by the way, spatially resolved things are also challenging. So it's a hard thing all around. Now in science, in most of these facilities, there's two things I want to say, including about Hubble, but in our big national, international facilities, there's two things that are key here. One is that the data is made public, so everyone can use it themselves. And the second thing, and this includes tests as well, is we put out calibrated data for the users. So I don't know if Adam or Wendy, do you use the raw Hubble data or calibrated data? Sometimes one or the other.

Okay. So with tests, I don't think with tests, we give both the raw and calibrated, but it's not detrendered. So there's a lot of terms floating around here. There's sort of a basic calibration that's often done by the facility. And then there's the detrending, the further data analysis you do on your own. So thanks to this intense scrutiny, Alma the Observatory, found a problem with the way they calibrated the data. Okay, so all the teams that have used the public data, almost all but one. also used the calibrated data, they didn't look at the raw data. So most of those, you can ignore them for now. This is a rapidly evolving situation. So we used the calibrated data. We had Alma observers, Alma data scientists on our team. And it had to do with how they used their calibrating object. I'm not going to go into too much detail here because we want to get to some other topics.

Yeah, we did a podcast also. I'll point viewers to my channel from last month. Yeah, but that can include all this latest. Yeah, they can have the background there. But hopefully you'll come back on the point. So it turns out that. When Alma's releasing the new public data that is, like, reprocess is, I think, tomorrow. And so we'll have all the teams can go back to bat to look at this calibrated data. So, yeah, a few people looked at the Alma data again, didn't see phosphine, but it's an evolving situation. Now, the thing I want to leave all of you with, though, is it will take some time for this to play out is because of our phosphine detection, someone, a team of people went back to look at the pioneer venous data. And we hadn't talked about this on our podcast.

And Pioneer Venus was a mission from the United States to Venus in the late 1970s that included different probes. And one of these probes had a special gas mass spectrometer on it. And when people went back and looked at this data, they actually, believe it or not, found quite compelling evidence for phosphine. And they found this neutral gas mass spectrometer ionizes the gases, whatever comes in gets ionized. And then it's subject to a magnetic field, which, which eventually, depending on the path of the ion fragment, can tell the mass and the charge. And so they found a bunch of phosphine fragments, including phosphorus, phosphorus ion, which there's nothing else that can be strongly associated with except for phosphine gas.

So, yeah, the mystery is out there. This could be a debate, not right away, because we've got to let things settle. But with Alma, JCP, and Pioneer Venus now, there's three different things to keep track up for you. Sarah, what about the other telescopes data? Not Alma, but Maxwell? Yeah, so one of the teams that re-looked at that data found the signal and then said, well, it's not phosphine. It's a contaminant. There's only one other possible thing it could be, which is a line of sulfur dioxide because Venus does, yeah, this is for like the non-planetary people. There is a lot of sulfur dioxide. But they had to invoke like a huge amount of sulfur dioxide in order to be able to match that line. Can you talk about the challenges of doing calibration? You were responsible for calibrating Hubble for some of the work that you did. And then what does it mean, first of all, to calibrate an astronomical telescope?

Don't you just get it from Amazon and go to work? Now, it turns out there's no, you know, there's no instruction manual. And you do have to calibrate it. So there are astronomers who work at a place called the Space Telescope Science Institute, which is sort of the headquarters for the Hubble Space Telescope. They run the process of receiving proposals from astronomers, what they would like to observe, awarding time, making those observations. But they also hold back maybe 10 or 15 percent of the observatory's time to obtain calibrations.

And calibrations are in some ways very boring, but they're very essential observations to be able to really make quantitative sense of the images you get. So it usually involves observing certain kinds of stars, maybe you know their brightness, ahead of time and so you calibrate the telescope. Maybe you observe those stars over the course of 30 years for Hubble and see if the detectors on the Hubble Space Telescope are decaying or changing if the field of view is distorting, if all the pixels are equally sensitive,

or if they're changing over time. So it's a lot of, I would say, sort of boring but critical measurements so that at the end of the day, when you apply these calibrations, you get these very pristine images that you can also do science with. You could also look at the brightness of a star

and know how many watts you're actually getting from that. So you could compare it to other stars. Well, I wouldn't say that you and Wendy are competitors in a certain sense. But Wendy, can you talk a little bit about the Hubble Space Telescope Key Project to measure the Hubble Constant, this paper that we're gonna give away a signed copy of that you graciously provided?

What does it rely on? Is it doing imaging? Is it really relying on these calibrations that your competitor? I mean, could Adam sneak something in there to make you get a different result? Just kidding. You would never do that. So we were looking at Hubble data early on. There were quite a time where when we made these measurements of distances to galaxies,

we weren't getting them right. And you were asking about that earlier. And so Hubble got this value of 500 for the Hubble constant. And then in the 1950s, that came down by about a factor of two. And then it settled into a regime where some astronomers were saying it was 100 and others were saying it was 50. Now, that's a factor of two uncertainty. We didn't know the scale, size of the universe to better than a factor of two. And that persisted for decades.

And in fact, was one of the motivations for building the Hubble Space Telescope. and it is, in fact, the project that led to deciding the final size of the primary mirror. It is that when the telescope mirror, the telescope was being desoped, it was originally supposed to be larger than the 100 inches that it ended up. It was a 2.4 meter telescope. And that was set by the ability to detect sephiates in a nearby cluster called the Virgo cluster. And so when Hubble was first flown, there was a concern that, that the time would be divided up into tiny little pieces because every astronomer had been waiting for this telescope for decades.

And so there were key projects that were set up. There was a peer review committee that decided what were the most important projects that Hubble and only Hubble could do. And measuring the distance scale was the primary project. And so our group competed for, got awarded the time on the Hubble Space Telescope to try and resolve this factor of two debate. And so the way we went about it was to use these same sepheid stars that Edwin Hubble had used based on the discovery by Henrietta Swan Levitt. And we measured the distances to about 24 galaxies for which we could make very accurate measurements using sepheids and tie into other methods like the type 1A supernovae that Adam mentioned that take you out farther into the Hubble flow. And we were able to resolve the discrepancy. We got above the Earth's atmosphere.

We were able to make corrections for dust. We weren't using photographic plates any longer. And we had many ways of measuring the distances independently. So you were asking, how did Hubble get it wrong? There were about four reasons why it was really wrong. And largely, it was the photographic photometry and the reddening. But we were able to correct for that. So we got a value of the Hubble constant of 17.

Now, today, so I've worked on Cepheid for a great deal of my career I know and love them, but what keeps me up awake is that there could be other kinds of what we term systematic errors. That is, there's some kinds of errors if you make a measurement over and over and over, sometimes you'll get too high, sometimes too low, but you can average over those, and the more times you make the measurement, the better your average becomes. But there are others that are systematic in the sense, for example, dust will only make your sephiate look fainter. It's never going to make it look brighter. And so that's going to take you in one direction or another.

And so that's one thing I've spent a lot of my career on is trying to devise methods for correcting for dust. And we were able to do that and overcome this problem. So one of the things, as we're approaching now, the need for higher and higher accuracy, What we did with the key project is we measured a Hubble constant to a 10% accuracy. So we solved the factor of two problem. And then Adam and others in the last couple decades have been bringing down the uncertainty with time. But now the need for even higher accuracy is upon us because we have other means of estimating the Hubble constant in the early universe, which I assume we'll talk about in a little bit. And so we have a need for even higher accuracy.

So one of the things that I've been doing with my group is to use a different kind of star than a sepheed. These are stars that are fainter than sepheus. They're older than sepheids. They're red giant branch stars. And the interesting thing about these stars, the unique property that they have, is they achieve a certain luminosity. And then there's a fundamental physics limit. They then become much fainter and they cut off it. They don't ever climb higher than a given luminosity.

So they're almost a perfect standard candle. We use that term. And the different in the sense than the supernovae or the sephiids that are standardizable. They have a luminosity that's constant. And you can see them, Brian showing here in the top panel, the white squares are the fields that we're observing with Hubble. Again, we're using the Hubble Space Telescope. And we're out in the halos of these galaxies. So unlike the sepheids that are in the disk,

The giant branch stars, they also occur in the disk, but they're easier to measure in the halos, and we can make the measurements more accurately. And you can see down below, so I'm looking now, it is harder to see in the image, but they're individual stars in the circles. Yeah, you can see some of them. So they're not crowded by the stars in the disk, and we can make these measurements really quite accurately. So on the left, you can see the stars in the circles there. So they're very simple and both from a physical standpoint and also from a measurement standpoint. So we've been recently measuring the distances in the same way as we do for sepheids in nearby galaxies, using the Hubble Space Telescope. We calibrate these stars, say, with geometric parallaxes nearby.

We measure the tip of the red giant branch in galaxies that, uh, also have type 1A supernovae and then we tie into supernovae that are much more distant. And so the interesting dilemma that we find ourselves in now is that what you measure for the Hubble constant based on these local determinations, that is measurements of stars in the local universe, when we compare those to what astronomers are measuring based on temperature fluctuations in the background radiation from the Big Bang. If you use what we now call our standard cosmological model to fit the data in the early universe, you can infer what the expansion rate would be today. And when we compare that to what we're getting from the sepheus or the tip of the

red giant branch, that value from high red shift is lower. The Hubble constant is about 67, whereas it's maybe 70 or even 74 locally. So the dilemma before us is, is this a significant difference? So if we look at the history, there have been a lot of uncertainties in the Hubble constant and the answer has been, there have been systematic errors we didn't yet understand. And when we corrected for them, we had a better measurement. So are there still systematics that we don't understand? Or is this a real difference, which would be the most exciting.

outcome because what it could mean is that we are learning something about the early universe and the model, standard cosmological model, could have gaps in it. We may be learning about new physics in the early universe. So that's what makes this an exciting problem. It's not yet a solved problem. And in a sense, it may leave us back where Shappley and Curtis were, you know, maybe some things are right, some things are wrong. But we don't know yet where those are. We're at the forefront and it's hard to see. It's very easy to see in hindsight. But it's exciting. Yeah, David's gone on.

What is that? I was just saying David's gone on record and a sworn affidavit that he thinks that there could be systematics lurking. And first of all, I want to ask David to explain what is the difference between the early universe cosmology measurements that you made with your team on WMAP and Act and other instruments. And Plank has now corroborated. And the late time and why they differ by the so-called 5-sigma tension that has grown.

grip the field. Why is this important? Why are these measurements so discrepant? And, you know, if you had to bet Jan 11's pet ferret's life on the resolution, what would it be? Well, there are, the way we measure, we measure the hopper constant indirectly in the early universe. What we're actually measuring in many ways is the size of the universe, which is related to the hubbock constant or the distance, really, to out to red shift of 1100. out the distance we look at, if we're looking at and we look at the microwave background. When we look at the microwave background, we're seeing a pattern of hot and cold spots. And there's a characteristic size we see set by the distance a sound wave can move.

So nature is basically holding up a ruler to us. And we know how the length of the ruler, we think we understand the physics, we think we understand the length of the ruler. And then by measuring the size of the hot and cold spots, we can infer, the size of the universe. And from that, if we have the right cosmological model, predict what the Hubble concert should be. Now, when we made the measurements with WMAP

over a decade ago, and that's a satellite that was involved in launching, we got a value of around 70. And with the error bars large enough, that was very consistent with the measurements that Wendy Friedman and her team made. And we really had a pretty consistent cosmology. On the microwave background side, there's been a lot of progress since then.

One big step forward was the Planck experiment, a European-led experiment with significant components in the U.S. that map the sky and even higher sensitivity. They got values around 67 or 68. There's WMAP. So completely consistent with WMAP numbers and the uncertainties. But now with smaller error bars and a smaller value. And that's something we've now been able to check in a number of different ways. So our measurements from Chile with the ACT telescope provide an independent way of measuring the Hubble constant from the microwave background size of the universe.

And again, we get a value bang on the plank measurements and combine WMAP and act completely independent measurements from plank. we get a very consistent set of numbers. So I think from the microwave background, I think we're unlikely to have systematic errors because we've got independent measurements making very similar measurements. Now, there's numbers. Now, you know, what has changed since then,

since its plot is there's been a reassessment of the Holy Cow measurements and the Holy Cow values which this is based on gravitational lensing and other technique we haven't talked about. But that value is now shifted down and is very consistent with the plank measurement. It's really kind of blank on that.

I'll debate that a little bit. Yeah, yeah, let's hear it. But that's what the people who wrote the paper said. And, you know, there really, I think, a couple possibilities in terms of exercise. explanations. The most exciting one is that this is pointing to new physics. One piece of potential new physics that I've learned on a lot of people are interested in is the notion that we've miscalibrated the ruler, that there's physics going on in the early universe, things happening back in the first, say,

100,000 years in the history of the universe, that we have not properly included in our model. It could be dark energy behaving in interesting ways at early times. It could be interesting new physics for neutrinos. There's a lot of ideas that people have been developed that would recalibrate the distance ladder and perhaps bring things into better agreement. That would be the most exciting possibility. The most mundane one, but still important, would be that there's something we're missing and our understanding of sepciates that's happened before.

And you know, Wendy could say more about this, but her measurements with the tip of the red giant branch, I think, are also turned out to be a local measurement consistent with the plank and WMAP and app, the C&B measurements. Yeah, and those are holding up with time too. So we have a couple more measurements that we're just finishing up,

and that calibration is. is holding up. And Adam, you wanted to... Yeah, I was going to say that, you know, in terms of systematics, in the past, people have thought of specific systematics that could involve sephiates like reddening or chemical effects. And so the generation of measurements that I've worked on, the shoes team, specifically address those by making observations in the near infrared to sort of look through the dust. And also by using the same telescope to calibrate the sepheids and look at the more distant sepheids so that flux calibration, which we talked about earlier, drops out.

And by looking in the near infrared where chemical abundance effects are mitigated. And so what we've seen, really, and it's not just the tip of the red giant branch or the sepiads, but there are surface brightness fluctuations, there are mazes, they're myros, there's telefishers. there's Tully Fisher. These are all different methods we use. And, you know, if you look at the sort of range of local measurements, it ranges from about 70 to 75. But that full range is above what David was saying. The full range that we see from the early universe is really about 67 to 69. The mention of the lensing measurements by relaxing certain assumptions they made about the mass profiles, they actually become quite unconcerned. straining, which is sort of neither informative about the early universe or the late universe.

And so, you know, we're in this position now where we're trying to figure out, okay, is there an error, but is it an error in theory where we are not understanding the model of our universe so that we can connect the early to the late? Or is it an error in measurements, as people have described as systematic error? And, you know, we're at the point now. The measurements are so good, I would say, on both ends, the early and the late side, that we're sort of getting past the point where people can sort of wave their arms and say, oh, new physics or, oh, systematic errors. And what we actually need now are specific ideas of how, let's say, a change in the cosmological model could match the observation so that we can test that because it's very difficult to come up

with an idea that's consistent with the data. And likewise, when people suggest systematic errors, at this point, we need a specific mechanism for how such a systematic error could be consistent with the various measurements we've seen in the local universe and yet explain the tension we see with the early universe. And so, you know, it's interesting to ask people, you know, what do you think, what is your gut feeling? But I'm more interested at this point in specific ideas that can be tested because, you know, that's how we always make progress in science is with, you know, specific hypotheses that make predictions, really, so that we can go out and test those. I mean, Adam, I disagree with the lensing measurements.

The value they quote is 67 plus or minus four. That's the same kind of errors that most of those results you have in that plot quote. Right. My understanding was that they had multiple ways, but they're within two sigma consistent now with Both. The low-b value is bang on the C&B value. And they had what they identified as a problem is something that many of us have talked about when we've looked at the previous work, which is the slend sheet degeneracy.

The fact that you don't know how much mass, what the mass distribution is around the lenses that they use. And what they've done is get velocity measurements to calibrate. and with that a measurement that now seems consistent. That doesn't mean that's the dependent of measurements, but I think it's now the plot that we're being shown right now is a little, I would argue, today with crime in 2018, but in 2020, and this shows how things progressed, is now a little misleading, the 2020 data for that wholly cow value,

when they properly account for the uncertainties and mass distribution shifts down to 67.4. Yeah, I'm just pulling up the picture. Yeah, I point out that the Carnegie plus plus or minus five and 67 plus or minus four. I guess they have two different ways of doing it, but I would agree that it's become unconstraining now. I don't think it particularly answers the question.

Yeah, I think that's- Sorry, you were saying something, Wendy? Yeah, just to add, so the Carnegie measurements that are referred to here, I just want to know, that they're based on the recent all sephiate distances too. So if that proves to be an issue, those would be there. And the tip of the red giant branch that we have land just below 70. So, so I just agree with David's point, both the dead of date, but it also, you have to be careful

what is calibrating where and the holy cow measurements made an assumption, which landed them on the high end. But when you get data that can actually actually constrain the mass distribution, it moved, and the uncertainties went up. So I think we're in play here now, and we just don't know where it's going to land, but it's not as simple as saying everything lands on one side or the other. Jan, I just want to ask you a question from the audience to speak. I know you have to break off pretty soon. Sorry, I do, yeah.

It's okay. They want to know if there's any in the Holy Cow results that rely sort of on the gravitational lensing, which is a consequence of Einstein's theory of general relativity, is there a role that black holes could play in the resolution, either primordial black holes that you talk about in Black Hole Survival Guide or other black holes in the resolution of the Hubble Tension, or is it just completely not relevant? Well, I love that somebody's trying to drag me into the conversation, but I think to a large extent it's really not relevant, but I'm going to take this opportunity of having a minute just to mention how interesting it is that

Hubble lobbied to try to get astrophysics considered for the Nobel Prize. I think he was well aware of the significance of what he was doing, but astrophysics was not considered under the Physics Nobel Prize for decades afterwards. And I think it's also really well for people to realize that at the time that Einstein was working and that his friend writes him a letter from the Russian Front to propose this thing that we now call Black Hole, Einstein did not know there were other galaxies out there. I mean, that's just tremendous in 1916. And so for Hubble to just have that realization,

but these objects are outside of us. It's why you started this whole thread with all these brilliant people on this call is because our concepts went from this to like, whoa, right? Suddenly the universe was bigger than that. So I wanted just to mention that piece of history because I think that's quite interesting. I don't think it was until, and I'm sure Wendy probably knows about Jocelyn Bell, who was overlooked in principle for the Nobel Prize for the discovery of pulsars.

That was the first that went to Anthony Hewitt was the first Nobel Prize in astrophysics. And of course, now we just had the announcement in October that the Nobel Prize went for black hole astrophysics. And so that was very exciting and the discovery of supermass black holes. But the other really cool piece of history I want to mention was about Henrietta Leavitt. That was just a phenomenal story. It's not just her. So she was a member of a group of women that were called Pickering's Harum, unceremoniously called Pickering's Haram.

Charles Pickering was the director of the Harvard Observatory at the time. And he had a bunch of male astronomers working for him and he got so fed up with them that at one point he said, my Scottish maid could do a better job. And he fired them all, so the story goes. I actually am not a historian, so I'm not sure this is exactly it. And he hired his Scottish maid, Willamina Fleming. And Willamina Fleming oversaw, Henrietta Leavitt and all of these female astronomers who worked for 25 cents on the dollar. And I mean, they were absolutely impoverished. Some of them had problems like we're going deaf. They were, you know, they were 11. Did you do death. Yes.

And me at 11 went deaf. I mean, it's a trend. And the glass plates are stunning that Wendy referenced. And there's this whole history of, of this Pickering's harem who collected these glass plates. And I don't know if the Harvard observer has retained them because there was some discussion of destroying them because they didn't know how to house them properly. But the history of that story is really, it's really very moving. And Pickering actually, actually, treated these women, I think, with a great deal of respect under the context of the time, right? In the context of the time, this was, he was doing his best. And I think they cared about him very much, but they, they, they were frustrated that they were so desperately underpaid,

that they were actually struggling in total poverty. And some of them were taking care of mothers and children. But, but, but the story, you know, that, Dave Sobel wrote a book called The Gloucels universe about Pickering's harem. And it's very interesting, last thing I'm going to say before I jump and I let these folks who are actual astronomers talk about data, which I find really exciting to listen to you, by the way, even though it's not, you know, I don't touch data. I love hearing about it. The thing that I want to mention about David Sobel and the glass universe was that it really,

It's, it's, it's, it's, people shouldn't rewrite history in this way. I've noticed that if you now go on to some of the old like Wikipedia pages, they no longer want to say Pickering's harem because they find it slightly offensive. And they no longer want to say what Pickering actually said, which was my scotch made. And, but it's very important that we remember these things because we have to understand the reality of what the context was and how tremendous it was that, um, Henrya Leavitt did what she did and how important. And how important. And, um, was that Hubble used that and used the science and that exactly that plate that you described, Brian, where he crosses out Nova and he puts in VAR, exclamation point. That's the epiphany. So I just, oh, there you have it. There you have it. Actually, Dave has agreed to come on my show and into the impossible podcast. I just want to say one more thing about Shapley because I think there was a human element. He was the director, Curtis was the director of the Alejani Observatory, Allegheny, observatory, which is part of the University of Pittsburgh. And then Shappley was at Mount Wilson, where Hubble made the measurements that would later, you know, cast doubt upon what the claims

that Shapley made and basically turn in favor of Curtis. But actually, I read that he was almost angling for a job of becoming the director of Harvard College Observatory, that that was why he he looked at the debate as his job interview talk. Yes, yes. Wendy, can you say more about that? like the human element of it all? Yeah, well, and there's another aspect of this, which is really fun part of history, which is, so yes, Shappley was at Mount Wilson where Hubble was and George Ilery Hale. And there's a story that Alan Sandage actually said to me was true, so I don't think it's just apocryphal.

It was that Shapley had photographic plates of the Andromeda Galaxy, and one of the really interesting pieces of history was that at that time when Mount Wilson, when the telescopes were being built, there weren't paved roads and there weren't cars when the 60 inch was being built. And they used mule trains to bring up the telescope tube and bring up what they needed to build the telescope. And one of the mule drivers was a man by the name of Milton Hummison. And he turned out to be, and I want to say more about Willamina Fleming and Henriette 11th after this too, Janica's related to this. But he ended up first working as a janitor on the mountain, and then he became an assistant to Chaplin to Hubble. And as the story goes, he was developing photographic plates for Harlow Shapley,

looked at the Andromeda Galaxy, and could swear that he saw variables. And he walked into Harlow Shapley's office and said, I think there are sepheids in the Andromeda galaxy. And because Shapley was convinced that that couldn't possibly be true, because that would have meant that these nebulae were outside this big milky way that he was arguing for. He took his handkerchief and rubbed off the places that Hummison had marked where the variables were and lost his chance to make the discovery of extra galactic nebulae. And then he later hired Celia Payne-Gabaskatchkin.

I can never pronounce her name. So Celia Payne-Gapachkin, she actually did. She was one of the first women to get a PhD at heart. Harvard. So Henriette 11th and that group of women that Pickering hired, they were not allowed to get degrees at Harvard at that time. And Willoughby and Fleming had been a high school teacher in Scotland. When she came over, apparently the story is her husband had deserted her. I believe she was pregnant at the time. So she ended up working at Pickering's maid. And he realized this was a woman whose talents were, you know, being totally lost and hired her. And she turned out to be a superb

manager of this group. And people like Henrietta Levitt and Annie Jump Cannon, I mean, there's just a huge number of women in this harem, as it was called, who did fantastic astronomy. But there were never granted degrees, and they were paid egregious wages, as Jana pointed out. And fortunately, the situation has changed. Willamina Fleming. I do love that, you know, we need to. You know, we to preserve that history because it is it is a it's a layered and complicated story and and it really is what launched this field and um you know i think we have to remember that and i think we have to remember that scientific integrity it's really important that it you know Hubble hubbilled didn't scoff at a woman's work and therefore not use it right so um so this is it apparently

was nominated for a Nobel Prize but she died she died before Hubble's discovery of galaxies and before, of course, his discovery of the expansion. She never realized the implications of her own work, which is just sad. She died very early. It set up the astronomy department at Harvard so that he could give Cecilia Payne PhD. Really?

Wow. Yeah. So the reason she's the first astronomy PhD at Harvard because the physics department wouldn't give a PhD to a woman. David, I thought that was also true of Harvard, the first PhDs were from Pickering Cairn in astronomy for similar reasons that they did. They just kind of created a new PhD program to confer PhD. Is that not true, Wendy?

They were not granted. I thought one of them, it's not Annie Jump Cannon. I can't remember. Who started the Vassar College Observatory? I'm struggling to remember now. Anyway, I didn't mean to derail the conversation. It's fascinating. I just, I do have to go speaking. I do have to go, but I'm going to listen on my way out to pick up my children. I'm going to listen. And I want to get back to the data because that's a really great stuff. Yeah, yeah. I want to get to the imaging too. Janet, thank you so much. Congratulations again in publication of Black Hole Survival Guide. It's one of our gifts. We'll be giving away. There's still time to register for the giveaway. I'll put the link in the thing. And while you're at it, exercise your finger. I always say make sure

those finger muscles are working and subscribe to the channel. Hit the notification bell if you would. you will get access to more great content like you heard. I'm going to have Davis Sobel. I'm going to have Sheldon Glashow on the show next week and Lenny Suskind and many other people. In addition to all these wonderful guests that I've had on so far. So let's keep going. I want to get to data. I want to get to imaging.

Bye, Janet. Thank you so much. Congrats again. An awesome, awesome book. I want to go to our Wyoming stargazers who are snowgazing tonight. And they graciously sent us some images of what the capabilities of their observatory is able to make. And I want to zoom in here. So we'll start with this, hopefully this video will play. I don't know, Sam, is this a video I'm going to try to play?

It's a YouTube video, yeah. It's a YouTube video. Okay. So it's going to ask me to link to a YouTube video. Okay. Well, I don't know if I can actually get that going and not lose the stream here. But I want to look at, ask Mike to describe some of these images that are shown here. Hubble images, and they're shown next to images made from Wyoming stargazing. And obviously, Hubble has certain advantages, but it is true that we can do an awful lot from the ground, and we will have some examples of citizen science that people can participate in if they're interested.

So, Mike, can you talk a little bit about the facilities at your observatory that we're looking at? Okay. Yes. These pictures were not taken by my, I didn't take these pictures. The ones that are going to come later are, but my observatory. which is in Jackson Hole, has three telescopes in it, one of which is a 20-inch plane-wave telescope. And these pictures, in fact, are taken by the 20-inch plane wave.

I also have a six-inch Takahashi refractor, and I have a 12-5-inch plane-wave. And I use these telescopes depending on the object. If the object is a small object, like, for example, the pillars of creation, which we're looking at here, I would use the 20 inch. But for example, the endromeda is real nebula, galaxy, excuse me, is quite large. And it's about six moon diameters in size. That's where the six inch telescope comes into play because it has a much larger field view. And then for the moon and the sun and planetary nebula, planetary observing, I use my 12.5 inch telescope.

and they are all in the same observatory. Right now they're getting snowed on outside, Russia. We had a great summer here and a lot of beautiful nights before the smoke from California came in. Now, we are definitely plagued by the atmosphere. Samuel, you were going to also talk about some of those, the plant, I don't know which we want to start with, the planetary pictures or these deep space pictures.

It's going to that. Either one. Yeah, let's look at the nebulae and then I want to get back to some of the discussion that we have. But yeah, actually, let's look at the Juno image. I want to talk about that. I want Sarah to jump in here with some commentary on opportunities for citizen science as Mike's doing here. But first, Mike, can you tell us a little bit about the Juno Cam images that you're showing here that you processed? You didn't take these.

These aren't taken from my own. No, no, no. I certainly didn't take them. But the Juno Cam project on the Juno satellite, was really left to amateurs to process the pictures. The cameras was taking these raw pictures and was left to amateurs. And I, being an amateur, I was fascinated by some of the pictures other folks had done. And I developed, I put together these pictures, like the one on the left actually has won an award in Wikimedia as one of the five best science photographs images of the year.

It's of the South Pole and it is a composite of pictures that was taken during the first, third, and fourth of the orbits that the Juno satellite made. And it was complicated because there wasn't a lot of overlap between the pictures. So I had to do a lot of handwork to make that picture. The one on the right was taken during the 18th orbit and it involved four separate pictures. taken at different distances from the planet. So it was quite a job assembling them into a single picture because I had to correct for the difference in the distances. But they both came out beautifully.

And it just, of course, the satellite is quite close. Compared to even the Hubble, there's resolution here in these pictures that are beyond even the Hubble images because the satellite gets as close as several thousand miles to the to the to the Jupiter when it's at its closest now when it's passing over the pole like on the left picture it's about 100,000 kilometers away the one on the right on the average you changed during the four pictures I had to use but on the average it was about 27,000 kilometers away taken from a direction taken from 40 degrees south so you can see the giant red

spot on the upper corner and you can see some of the same parts of the image that we're seeing on the left at the very bottom. So you're seeing the South Polar region as well. Now, Sarah, can you talk about there's, I found online the American Association of Variable Star Observers has a link to opportunities for folks to help with analyzing test data. Can you talk a little bit about opportunities for people that might be listening to get involved with actual research conducted by professional astronomers? Yes, actually. You can also Google on planethunters.org, and it will relink you to a website for crowdsourcing.

And what the mission does is the people who organize this, they take test public data and they chop it up into pieces, and you can train yourself on a tutorial on how to find planets by the transit method. And it's actually highly successful. Every year, there's a couple, a few maybe planets found by crowdsourcing that the professionals missed. Oh, wow. Yes, I'll have a link to that in the comments in just a second. Really good. Okay. So let's look at one more slide here from Mike's images and then we'll get back to, we'll get back to some great debates. But I do want to talk a little bit about Novee and so forth. So we lost our black hole expert, but I want to talk about these images and as well as what they, you know, what they may pertain. for settling these future great debates.

If we have opportunities, I'd like to know, actually, since we still have Sarah's attention, can you talk about the next upcoming missions that you're involved with, building on the Tess legacy, first of all? There's so many missions. My favorite mission is actually this, I'm leading a concept study on a mission to Venus,

where we look directly for signs of life and for life itself. We have a small, medium, and large mission we're studying. Small, we're going to partner with rocket lab who are planning to go to Venus. They already have funds and plans to send a small rocket to Venus, which would have a very small payload, and we're helping choose the science instrument. But back to exoplanets, everyone's waiting for the James Webb Space Telescope to launch. In fact, proposals for the first cycle are due in a couple of weeks, and I bet every exoplanet astronomers working hard. We want to

study planet atmospheres, and it's going to be big. can you say more about what James Webb will do and what its prospects for launch and so forth, the challenges thereof? Well, James Webb is the most complicated, in many ways, engineering and science project ever launched. It's this incredible telescope that will be much larger than Hubble, and because it operates in the infrared, able to stare much deeper in the sky. And I think it's going to have significant impact on many of the questions we've talked about. You know, Wendy could say more about this, but for things like tip of the red giant branch,

the fact that you've got a powerful telescope observing in the red or the infrared that has much higher resolution that Hubble will enable us to use those techniques to go much further out. And that may be one of the things that, you know, I think, for this Hubble discrepancy, it is having new types of data is going to be the way we'll make progress and hope then one of the things JWA E.EST will give us is new types of data. I think it will also have enormous impact

on our study of planetary atmospheres. Sarah Seeger spoke of the Tess mission and Tess is finding planets that transit, in front of their host stars. Those planets will be targets for the James Webb Space Telescope that will be able to observe basically sort of before and during and after images. So you'll watch the spectrum of the star before as the planet moves in front and afterwards. And that will enable the detection of the properties of atmosphere,

around other planets around other stars. So that's among the things we're all excited about with the James Led Space Telescope. Yeah, I was just browsing the guaranteed time observer projects today. Like if you have built an instrument or have some other special rule, you get time, like guaranteed for you. You don't have to propose, actually. And there's so many transiting planets already in those lists.

So we'll be seeing results, probably among some of the earliest results who we might hear about are about transiting planets. Oh, it's really exciting. I think every time we made real progress, it has been jumps in our technology. The technology has improved. I mean, we saw it with the debate in the Hubble constant. Last time, then you get above the Earth's atmosphere,

and you suddenly have this capability you didn't have before, and you make real progress. And I think, yeah, we're really looking forward to a new instrument that's sensitive to the infrared. it has higher resolution because we will be able to push farther out with the tip of the red giant. I have, so we have about 10 minutes left and I do want to get the questions, but Adam sent me some fresh data. This is fresh data. It has plots from. Yeah, I thought you've got a very out-of-data plot there before, which, so this is a compilation.

I didn't do this, but this was a paper last week. This sort of shows the most recent measurements, maybe in the last two years or so. And what is labeled here as indirect is what David was referring to, observations from the cosmic migrate background and the cosmological model used to predict the value of the Hubble constant. And that kind of peach, orange-looking band

is sort of where those measurements prefer. And then below the dotted line is the direct. And so those are the local measurements and the various techniques that we've discussed in this, the sepheeds, the tip of the red giant, Branch, Myras, Mazers, Tully Fisher. And I mean, you could see the issue here really quite clearly, I think, is that there seems to be an offset between these two sets of things. It doesn't really

look like the direct measurements are drawn from that peachy kind of band. And certainly there are some variations. There's some noise here. But, you know, as we try to make this comparison and convince ourselves, we really understand the universe from the beginning to the end. You know, this is not a very convincing result of that. So certainly, you know, more measurements and better techniques. But, you know, as I was saying before, it would be really valuable if people have specific ideas of what is in common with the measurements either on the direct side or the indirect side that could cause one group to shift with respect to the other. I mean, you know, we could always sort of pick our favorite measurements, but that doesn't really give us a working hypothesis

of what produces this difference we see. I don't know if, and David, the barrier lensing measurement is at the bottom there. So I think that's the one you were referring to. But I don't know, David, if you have an idea of like what could be in common with these, that could be a systematic even. I mean, the things that I've looked at most are the lensing, and I was really pleased on these measurements to see the bureau analysis, which I think is superior and does include the uncertainties in the mass profile. And what are the assumptions we make in the indirect ones? And we've been looking very closely at things like neutrino interactions, and one of the interesting features that has that makes clear predict. about what the microwave background fluctuation should look like on small angular scales. So we're right now doing an analysis where we're taking the data we've measured from Chile

and asking, could we change our cosmological model? And in doing so, change, shift where that peach curve would be, because all of those techniques assume we know the length of the ruler. So if we can change the length of the ruler, that's the way we would. shift the peach curve. I think on the, you know, the purple curve, you know, with the tip of the red giant branch numbers, you know, lie somewhat in the middle. And with sepheids, I mean, you know, we, I think, well, our best hope is if we have,

with James Webb, we will have more data, higher quality data, and we'll either confirm of those numbers and the arrowbars will get smaller, or we might discover something new about their properties or some subtle effect that we've missed in the past. One of the exciting missions that we haven't mentioned, really, that actually relates quite directly to this is a European mission called Gaia, which is measuring the parallaxes of billions of stars, and in particular is measuring the parallaxes of some of these star types that we use to measure distances. And so Gaia is due to have their data release three in three weeks, I think.

That will be a very exciting moment because that should, could give us the kind of precision that we need to truly reach a 1% measurement locally, the direct measurements of the Hubble constant. You know, one never knows what to expect when a new data release comes out from a new facility, you know, how it will recalibrate things. But that is certainly something to keep an eye on. One of the cool things Gaia did was they, I mentioned early on this Von Maughan result that was an attempt to measure the distance through Andromeda by looking at its rotation. And Van Manen got it wrong. But Gaia had the precision to finally be able to measure that effect at that distance.

And so rotational parallax? Rotational parallax. Not at the precision needed to really tell us something about this. question, but it's kind of cool that it took a hundred years to do the Von Manu measurement right. That's where Curtis was right. He just didn't believe that that Von Manin could make a measurement that small. But Curtis was actually wrong because he didn't believe that Sefayans could be used to measure distances. So there were a lot of who won that debate. They both won in some ways and lost in other ways, which I think is a good lesson for the present. I also wanted to jump in and

defend one other aspect of Hubble's original measurements. You know, we talked about, you know, some kind of systematic errors. There were also two generations of stars, so-called pop one and pops two stars, and a, you know, not realizing that fact, but actually calibrating the luminosity of one type locally and then observing the other type far away and not realizing those were actually two different types of stars. That led to- Yeah, those populations, right? So one of our viewers is asking, what makes them pulse in the first place, and then what makes them the two different populations

of Cepheid pulse at different properties. Right. Well, so Cepheid, like all stars, have an exquisite balance between gravity, crushing the star, and a kind of thermal pressure, all the heat from the star pushing back. And that's called hydrostatic equilibrium. Normally, a star sits right there in that perfect balance. But there are mechanisms in stars, in particular in their atmospheres, that cause stars to overshoot that. Sort of like, you know, kids sitting on a swing can sit happily, you know, at the bottom of the swing, but given a little push, we'll go back and forth. And in the case of the Cepheid variables, there's an element of their atmosphere that

causes a greater opacity and can push, like somebody pushing on the kid's swing, that started to become a little bit bigger. And then at that point, gravity starts to win as the star cools off. And then it shrinks again. and then it overshoots. So it's a kind of instability that causes this constant overshooting around equilibrium. And then the two different populations that he was unaware of? Right. So that, you know, in the first generation, there was not a lot of what astronomers call metals, which is really just means anything heavier than hydrogen or helium. And so stars had a somewhat

different composition than once a generation of stars was able to fuse heavier elements in its core and then spew those elements out into space through supernova explosions, gravity sweeps up those heavier elements and the next generation of stars still mostly made of hydrogen, but now have trace amounts of these heavier elements and it can subtly change the properties of stars. It could change their luminosities and colors a little bit. So those are things that astronomers now know and calibrate but did not know back in Hubble's time. And these other population of stars are actually lower mass and older stars than the population to sepheids. So they're less luminous.

They're a completely different beast. Wendy, someone's asking you in the chat room about our tip of the red giant branch star is more immune to certain types of systematic errors. Intrinsically, not by virtue of the fact they're on the outskirts of the galaxy. Yeah, I think there are some reasons that they are. I think they're simpler in the sense that, as I mentioned, they don't get brighter than a certain luminosity. And so these are stars, they're solar mass or so. When they exhaust the hydrogen in their core and then they begin to collapse, the central parts of these stars become degenerate. They're supported by electron degeneracy pressure.

And then they have a hydrogen burning shell. And the stars ascend what we call the red giant branch. Temperature is increasing until it reaches about 100 million degrees. And then you have enough. So then you can start to burn helium stably. And the star, the degeneracy is listed. The star no longer is at that luminosity. It rearranges itself and falls onto what we call the horizontal branch.

And so the physics of that is very well understood. And people have been modeling that for decades. It's extremely well understood. Physics, all the models predict this. And so we don't have to worry about pulsating atmospheres. The metallicity of these stars that we've been talking about, any elements that are heavier than hydrogen and helium, are reflected directly in the temperature or the color of the stars that we observe.

With the sepheids, Adam mentioned before, that we can make corrections for the metallicity, and this is something that, in fact, I and a collaborator Barry Madur devised very early on, was to look at the abundances in the gas near the sepheids. Sephardians are too faint to measure their abundances directly. You have to get spectra to measure their abundances. So it's a proxy. It's not a direct measure of the metal abundance. Whereas for the red giant branch stars, we measure the color, two filters, that's all we need,

and we know what the metallicity is. It's a one-to-one correspondence. We know what the luminosity is. We know what the metallicity is. And we don't have to worry about pulsations. When we're out at the halo, we don't have to worry about dust. And so I think there are many reasons that they're less complicated. And what still concerns me about the Cephians is, yes, we can make corrections for reddening, and that's something in fact I did in my PhD thesis when we first were able to get CCD detectors and get multi-wavlength photometry

and then ultimately with two-dimensional red detectors to go out into the infrared. You can measure the extinction really well. But the worry is because of this difficulty when the stars are in the centers or in the disks of galaxies, it's hard to measure their brightness as you're pushing farther out in distance. So you've got potentially the stars are being crowded and blended with other stars, particularly in the infrared. And the sort of nasty part of this is it's the red giants

that are doing the crowding and blending as you go to the infrared. So you're trying to simultaneously correct for the metallicity, which may or may not be reflected by the young gas phase, trying to correct for the reddening and trying to correct or at least estimate what the crowding effects are. So you have to do this as a system and maybe each of these effects is only 1% or so, but maybe together, collectively, there are a bigger effect than you think. So I got to jump in here in defense of keeping awake at night of why we started to measure the tip of the red giant branch stars is you won't get to the bottom of these kinds of effects doing one type of measurement alone. So the sepheids are what they are, but we're pushing them out. So Hubble increased our resolution,

But the farther out you go, you lose that advantage of the resolution of Hubble. So that's why I think we need to take the next jump. We're going to add a minute. Jump in here and defend the sephiads. So I think the elegance of the sephiates is, you know, every individual sepiad gives you a distance. And so when we look in a distant galaxy, we don't just get the distance to the galaxy. We get many hundreds of measurements of the distance. And so you get to check this sort of internal consistency.

You know, one of the challenges, I think, really, of the tip of the red. Also with the red giant branch, right? You get hundreds of stars. With the tip of the red giant branches, there is no such thing as a star that is the tip of the red giant branch. It's a feature, a break in the luminosity of many stars. And so you have to correctly measure where that break is. You don't get a cross check. You don't get many measurements.

You just get sort of one shot at that. And, you know, when you look at the- You have many measurements of these stars. It's very difficult to actually see, you know, have I properly measured the break? where have I measured a kind of ripple in the luminosity function? And so I think that, you know, as we, you know, are able to move to the near infrared, particularly for Sephians to get through the dust and observe many of them, I think we've gotten very clean measurements.

I, you know, at this point, I think, you know, it's hard to beat sepians in terms of their range and their repeatability. Well, you know, well, it would slightly disagree with you, Adam, in the sense that we have hundreds of stars in some cases, thousands, to find the tip. And so, you don't get the tip from any one of those stars. You know, you have to look at all of them and just get one number from that. Yeah. So we got to wrap up because YouTube is closing down on us. Actually, at one point they had a, they had a warning and it said, go to Wikipedia if you're concerned about flat earth debates. So we can agree on a flat universe. Yeah, we're being

shadow ban. But I want to ask all of you in the remaining precious moments that I have with my friends and colleagues. Let's start with Sarah. What and not in your field are you most interesting in discovering if you can come back in 100 years or you keep taking your vitamins and you live to be 100 years older. When you come back in the 200th anniversary of the Great Debate, what thing will you most want to know if you're coming out of suspended animation? What other outside of your own field? What would you like to know most of all in 100 years? Well, I think mine would be pretty simple. I'd like us to have images of the very first objects that formed in the universe. You know, the James Webb is supposed to see back to first light.

I don't know if it will, but I think I'd love to just know what really happened in an image, not in inferred information. Very nice. And let's go to David. What would you like to know most of all outside of your particular field of expertise? What fact would you most like to know in the year 21-20? Are we alone? Are we alone in the universe? Fascinating. Great. How about you, Adam, outside of your field, outside of the very fascinating

subjects that you study, what do you most want to know? Yeah, well, you know, I would like to know what dark energy is. We haven't talked too much about that, but, you know, that is extremely interesting. I had a second on my mind also to know what LIGO, the gravitational wave facilities, actually what the census of the universe in the dark sort of yields very interesting that. And Wendy, what about you? What outside of your field? Would you most be curious to know the answer to in the year 2120? Yeah, I think I'd have to say too. I'd like unambiguous evidence. Is there a life elsewhere? And I think that's going to be a fascinating field to break open. Thanks. And then Sam and not just bacterial life. Yeah, not not slime mold.

You want Bach, not bacteria. Sam Singer, director of the Wyoming Stargazing Association. Thank you for sharing your time. What would you most like to know the answer to outside of your field of expertise? I'm with David and Wendy. Not just a detection of, you know, one form of life, but how many intelligence civilizations are out there. And Michael, last but not least, thank you so much for sharing your images. What would you be most curious to know the answer to in the year 2120? Well, I'd like to know the answer to this debate, for one thing, because this debate is fantastic, has been very interesting.

And also, what is dark matter? What is dark energy? Very good. Well, I do want to thank all my illustrious guests. I thank you so much on behalf of me, my audience, et cetera. I want to remind you all to please subscribe to my channel, Dr. Brian Keating, on YouTube, but also to subscribe to the Wyoming Stargazing Association's channel. We're trying to get them over the 100 subscriber mark tonight.

So hopefully people can do that. I put that link also in the chat. Sign up for the giveaways so that you may too win a copy of either. Jenna Levin's new book, Black Hole Survival Guide, Sarah Seeger's wonderful book, which she promised to come into The Impossible Podcast for a solo episode, The Smallest Lights in the Universe,

losing the Nobel Prize, which you can get anywhere. Books are discarded. Adam Reese signed copy of the paper that brought him a good fraction. Better not go up on eBay. Yeah, better not. Well, I want to see who got more,

you or Wendy, because Wendy's lovely paper, the Hubble Key Project is also signed and available to two guests will win one of these. Are there two people win each one of these, each one of these, one of these, one of these, one of these, one of these, David, you're going to send me a beer cozy. You promised that you signed or something like that. Something else that's cozy maybe. I want to thank everybody so much.

This has been so spectacular. I hope we can do it again in 100 years. But even before then, I hope we can all get together. We should be well and enjoy many great debates like this, and contradistinction to the political debates. These are done with great comity and comedy, and I had a wonderful time. I can't thank you all enough. If you enjoyed this episode of Into the Impossible with Professor Brian Keating,

please subscribe, comment, share, and review. Watch on YouTube, listen on iTunes, Spotify, Google Player, Stitcher. We appreciate hearing from you and are always open to your suggestions for future episodes. For more information, and to sign up for Professor Keating's mailing list, go to Brian Keating.com. Follow Professor Keating on Medium and Twitter at Dr. Brian Keating, D.R. Brian Keating. For more information on the Clark Center, go to imagination.ucsd.edu. Into the Impossible is a production of the Arthur C. Clark Center for Human Imagination

at the University of California, San Diego, in the Division of Physical Sciences. Eric Vary, Director, Brian Keating, co-director. Produced by Brian Keating and Stuart Volko.