Into the Impossible With Brian Keating - Nobel Prize Winner Adam Riess: The Hubble Tension is Getting WORSE! (#231)

Episode Date: May 29, 2022

Chat with Nobel Prize winner Adam Riess about his team's newest measurements of the 'most important number in cosmology' the Hubble Constant. Using the Hubble Space Telescope for what it was meant to do, Adam's team continues to make ultra-precise measurements. We'll also explore the Hubble Tension, the future of Hubble now that the James Webb Space Telescope has deployed, and other cosmic conundrums. Adam is a brilliant teacher and a wonderful raconteur. Don't miss your chance to chat with a brilliant scientist about the most important topic in cosmology today! From the team: https://hubblesite.org/contents/news-releases/2022/news-2022-005 From CNN: Measuring the expansion rate of the universe was one of the Hubble Space Telescope’s main goals when it was launched in 1990. Over the past 30 years, the space observatory has helped scientists discover and refine that accelerating rate – as well as uncover a mysterious wrinkle that only brand-new physics may solve. Hubble has observed more than 40 galaxies that include pulsating stars as well as exploding stars called supernovae to measure even greater cosmic distances. Both of these phenomena help astronomers to mark astronomical distances like mile markers, which have pointed to the expansion rate. In the quest to understand how quickly our universe expands, astronomers already made one unexpected discovery in 1998: “dark energy.” This phenomenon acts as a mysterious repulsive force that accelerates the expansion rate. And there is another twist: an unexplained difference between the expansion rate of the local universe versus that of the distant universe right after the big bang. Scientists don’t understand the discrepancy but acknowledge that it’s weird and could require new physics. “You are getting the most precise measure of the expansion rate for the universe from the gold standard of telescopes and cosmic mile markers,” said Nobel Laureate Adam Riess at the Space Telescope Science Institute and a distinguished professor at the Johns Hopkins University in Baltimore, in a statement. “This is what the Hubble Space Telescope was built to do, using the best techniques we know to do it. This is likely Hubble’s magnum opus, because it would take another 30 years of Hubble’s life to even double this sample size.” Adam Guy Riess (born December 16, 1969) is an American astrophysicist and Bloomberg Distinguished Professor at Johns Hopkins University and the Space Telescope Science Institute. He is known for his research in using supernovae as cosmological probes. Riess shared both the 2006 Shaw Prize in Astronomy and the 2011 Nobel Prize in Physics with Saul Perlmutter and Brian P. Schmidt for providing evidence that the expansion of the universe is accelerating. https://www.stsci.edu/~ariess/ Please Visit our Sponsors: LinkedIn: LinkedIn.com/impossible to post a job for FREE Athletic Greens, makers of AG1 which I take every day. Get an exclusive offer when you visit https://athleticgreens.com/impossible AG1 is made from the highest quality ingredients, in accordance with the strictest standards and obsessively improved based on the latest science. Connect with Brian: https://twitter.com/DrBrianKeating  https://facebook.com/losingthenobelprize  https://instagram.com/DrBrianKeating  Please join my mailing list; just click here http://briankeating.com/mailing_list.php  Produced by Stuart Volkow (P.G.A) and Brian Keating Edited by Stuart Volkow Music:  Yeti Tears Miguel Tully - www.facebook.com/yetitears/ Theo Ryan - http://the-omusic.com/ Learn more about your ad choices. Visit megaphone.fm/adchoices

Hello, Into the Impossible Family. It's me, Brian Keating, your fearful host. On this ride into a multiverse of minds, today's guest is none other than my friend, Adam Reese, who's a towering figure in astrophysics. He is a Nobel laureate. He is the Bloomberg professor of physics at Johns Hopkins University. He works on the Hubble Space Telescope

and will soon be working on the James Webb Space Telescope data You'll hear an interesting shout out to data coming from that in today's episode. And we got into a lot of very technical details about how he does what he does and some really interesting red meat or red tofu. Do you prefer my vegan friends out there? I love you guys. We talked about what real professional astronomers do. And we also talked a little bit about how we should do what we do. Some advice to budding astronomers and their mentors to make life in the astronomical universe.

more pleasant and more open and really make it more fun to show up at work. It's not an easy job. Despite it being incredibly fun to be an astronomer, as I say, if you had told me when I was a kid, I could get paid to be an astronomer. I would have said, can I also get paid to be an ice cream taster? It's a wonderful job. There are challenges. It is a job as well as a avocation. So I really have always been infected by Adam's wonderful personality. He has got it all, and he's just such a good friend. I'm so glad we had him on the show. And let me know what you thought of this episode.

It was recorded live with comments from the audience, questions and comments from my audience on YouTube. I do encourage you to subscribe to my YouTube channel, is Dr. Brian Keating. So you too can ask questions of upcoming guests. We do live streams, semi-impromptu me. I've got such a word. And I want you to be a part of that conversation as well.

You can also leave me questions on my website at Brian Keating. I have a little new kind of widget where you can ask a question in a voicemail format. You don't have to even give your name or your address. Just go there and press the button and send me a message. I'd love to get it. And I'll even endeavor to put those on the podcast if you are so willing to let me know if you're willing to let me use your voice because sometimes I get tired of hearing my own voice.

But today I got to hear a lot of Adam and I hope you will enjoy it too. So pronounce it back and relax and enjoy this. ride into the universe exploring why is the Hubble constant not constant why does it change what tension does that cause for astronomers and where adam is most excited to see physics and astronomy go next and that is the subject of today's podcast let's go any sufficiently advanced technology is indistinguishable from magic open the bob bay doors please help but now we are talking about external galaxies with a galactic astronomer, meaning that he is one of the best in the whole galaxy.

And it's my friend, Adam, Adam, where are you joining us from today, Adam? I mean, Baltimore, Maryland. Ah, beautiful Baltimore. The crab cake capital of the world. I remember visiting there when I was a nine-year-old visiting Baltimore for the first time and seeing all these bail ponds places. And I remember one Adam, and it said their logo, their motto was, we get your feet back on the streets. And I just thought that was so sweet.

You know, I thought it was one. So it's great to see you again. We have many, many people watching online. We have questions coming in rapidly. And we'll let the chat room kind of fill in. And first of all, I just want to say, it's great to have you back on the show. You're a three-time guest now, and you've been so generous. And the time that we, since we talked last, have been a lot of developments in your universe

and then cosmology as a whole. and we want to talk about all that and take questions from the audience, because I have the brightest audience in the known universe. And they're just champing, you know, chomping or champing or chomping at the bit to talk to you about these new results. So first of all, I want to begin by maybe just getting from you. What has been achieved is so spectacular. I'm teaching cosmology this quarter, and I want to get your input on some of this.

but I always, you know, I have to brag and name drop. And actually, this is my office hours now. So physics 162 students, you're being monitored in the chat room. You have to ask a question and you won't pass the clock. Just kidding. But here's your chance to talk to a renowned astronomer. Yeah. Stump the champ, yeah.

So we talked a lot this year, just in the last couple of months, about the mysterious universe of things like supernovae. I don't want to ask you first. So I brought in this year, Adam, and then I'll let you talk because I'm sorry. I'm just so excited to talk to you. But this year, I decided to do something new in cosmology. You just do lab demonstrations. Can you imagine lab demos in a cosmology class?

So I brought in like Bunsen Burners and Black Bodies and Doppler shift things. But now I brought in actually a supernova. So I have a supernova core collapse, which I'll send you because you're chapter one in my most recent book. It's like a Huberman sphere, right? Oh, that's right. Yeah, very good. So we can do a demonstration of supernova. What fascinates you the most about these objects? How well do we know what they are? Are they really standard candles that I preach to my students? Are they not standard candles? Right. So just to be clear, there's two basic types of supernova. The kind in your hand is the core collapse, and those are when massive stars collapse and then rebound and explode. And the kind that we use for cosmology is a different type. They're thermonuclear supernovae, what we call type 1A, which is kind of a taxonomy name,

but what we really mean is a white dwarf that approaches the Chandr-Sakar limit, which is, as we know, a sacred limit, a physics limit, that 1.4 times the mass of the sun, that electron pressure cannot hold up the star, and you get runaway thermonuclear explosion. And so when you ask, are they good standard candles, you know, the Chandr-Sacar limit gives us a reason to believe that they ought to be, pretty good standard candles. In fact, you know, there is nothing else I'm aware of at that kind of scale where we get a nice physics limit like that, that gives you a reason to believe that they would

all blow up at the same luminosity. Now, there are small variations, and with those we can empirically calibrate. And so that's what we do. And then we see these very far away, and they're as bright as five billion solar luminosities. And so we can see them very far away and gauge the expansion rate of the universe. And before that, the gold standard was, or Cepheid variables. And I've always been a little confused. How did we, you know, Levitt and Hubble and Slyfer to whatever extent he was involved in that, how did they calibrate so accurately the period luminosity relationship?

I mean, it seemed like they didn't even know about what the nucleus was back then in the 19th teens. How could they possibly know with confidence that Cepheid's were these nuclear processes? when they didn't know anything about nuclear physics. Right. So part of the answer is they didn't calibrate them very well. They calibrated them very poorly. And so the consequence was misgaging distances in the universe by a pretty dramatic amount, by close to an order of magnitude.

And so that has been the journey we've been on for a hundred years. I would say, you know, when Henrietta Levitt saw sepheant variables in the small Magellanic cloud, right? right she recognized well they're all equidistant to us and so the fact that their period correlates so strongly with their brightness told you that they were excellent standard candles but this quest to figure out exactly what their luminosity is and therefore be able to use them to gauge distances and the expansion rate the Hubble constant that's been the hard part that's what's taken us i'm going to say a hundred years and we'll go on into the future but that's really what the news is, is that we think now we've calibrated them very well.

How much would you give in terms of children or teeth that you were kind enough to offer to pull one of my teeth so that we could make this? How much would you give for a supernova of any kind at a redshift of three or two or something like that? Is that even in the realm of possibilities? And if it were, would it just nail this forever to have such a high redshift, you know, calibrated a standard candle or am I just wishfully thinking? Yeah, actually, what's interesting is to measure what we've been talking about most recently, the Hubble constant, we actually don't want to go to particularly high Red Ship. We want to make extremely precise measurements all in the local universe. So the action here is all at Redshift less than 0.1.

It's all, you know, 100 million light years or hundreds of millions of light years because we want to be able to compare to how the universe looked early on in your, you know, your bailiwick, the cosmic microwave background, and compared to what the cosmic microwave background plus the standard model predicts the expansion rate should be today. Right, and that's where the tension will come in and we'll get into that tension. And as I've said, we need to have a cosmologist-friendly therapist for the field. And I want to get into your favorite non-supernova-related tension. We'll get to that. There's a lot of tensions coming up.

And as your fellow Nobel laureate, Stephen Weinberg once said, physics thrives on crises. But he said, luckily, there aren't that many crises. I think that's really... That is something I certainly would want people to understand is when they hear us talk about crises and tensions, they might hear it like it's a bad thing. And to us, this is the only way we move forward is to find places where our understanding breaks down. And so this has been the path forever of something. science is we have a model, you know, all models are useful, but none are correct, and we apply that

model, and it breaks somewhere, and that allows us to learn more. Yeah, I think that's so exciting, and there's a surfeit of these crises. A question that I got during this class, at least I think it was a question. I was talking about the fundamental parameter of interest in cosmology. Of course, the Hubble Constant that you're so expert in, is, has been called the most important important number in cosmology. Then after that, Sandage and others called the deceleration parameter, which you have more than your fair share of experience because you measured, it was negative for the first time with your collaborator and past guest on the podcast. I've had Brian Schmidt on since we last chatted, and he's a lovely man. And I do want to talk about some of the non-astronomically

significant, but still astronomically significant in terms of career advice that he gave to me. based on his experience with you and being kind of a colleague and mentor with you and the lessons that you guys learned to improve the culture of astronomy. I know that's so important to you. You've been actually a really quiet, you know, a champion of inclusivity

and developing this community in a way that few people knew, but, you know, they say the most, the kind of most righteous people are hidden, hidden righteous. And I always say, I want to be the most famous hidden, person in the world. But anyway, we'll talk about that later, because I think you have

extremely deep insight that hasn't been shared maybe so much on podcast like this. So maybe we can get into that if you all for indulge me. But I want to get back to A. So A, the scale factor is this immeasurable object, this entity that kind of governs everything. The first derivative evaluated today is the hubb of constant. Second derivative is related to the deceleration parameter. And then one of my students stood up in class and said, what about the jerk? And I was like, What did he call me? What did you say? No, I said, is this about Steve Martin, the great mother?

How come nobody talks about jerk? First of all, what is the cosmic jerk? And does anybody study it? It's peak pollination season, and my business is scaling fast. To keep the nectar flowing, I need a phone plan with top priority data speed. That's why I chose GoogleFi wireless. My connections stay strong even when the hive is buzzing. Plus, unlimited plans started $35 a month.

Now, that's a deal. That doesn't stay. Explore GoogleFi Wireless plans today. Plus taxes and government fees. GoogleFi Wireless is not subject to data traffic deprioritization during times of high network usage. Yes. So what we're talking about in general is looking at the universe expand and quantifying that by a series of derivatives or changes. So like any object you throw, an object you could talk about its speed, and then you could talk about its

changing speed, it's acceleration, and you could talk about it's changing acceleration, which is the jerk. And so in the case of our universe, the universe does have a jerk, and it's not me. It's not you. But it is the transition from accelerating to decelerating. And so we believe that the universe was matter dominated in the beginning because everything was very close together. And so attractive gravity would dominate simply because the separation between objects was small, at which point the universe would be decelerating. Then as it grew in size, then matter was more spaced out, and then this dark energy, which was sort of wading in the wings, became the dominant source of gravity, and the universe

began accelerating. So by definition, if you change from deceleration to acceleration, you have a change in the amount of that. And so that is the jerk. the third derivative and it has been measured. We measured it I think first was supernovae in the early 2000s using the Hubble Space Telescope. At that point our goal was just to see if you could see that transition and you can. It's been measured more recently with barion acoustic oscillations and other techniques like that. So if the universe did not have a jerk, then we'd be

in big trouble in our understanding. That would be an even bigger tension than the ones we've been talking about. Something to look forward to. And an allied concept that I talked to the students about in this year's cosmology class had to do with the notion of what you guys call the distance modulus. The symbol is mu if I'm correct. And that's sort of the difference between the apparent magnitude and the intrinsic magnitude, which can be related to the observed flux of an object, which we detect and we can classify and quantify. and then the intrinsic has to do with the ability to standardize these candles. And I think when we spoke in late 2020 with Wendy Friedman and others about the Hubble tension as it was back then, there were some thoughts that she had brought up about other

objects that could be the capital M in the distance modules. What has been going on in that field? Because I believe I'm not correct. If I'm not mistaken, rather, you don't study particular, you know, these different objects, tip of the red giant branch or whatever they're called. But what's been the most exciting or interesting developments in that field? And how does it play into the measurements that you and your colleagues are releasing recently? You know, to me, one of the biggest developments just in the last few years in this whole game

has been a new satellite, Gaia, this European satellite, which has the means to measure parallax, which is really the bold standard of measuring distances. observe an object over the course of a year and you watch its position change as the earth goes around the sun. And just by knowing the diameter of the Earth's orbit and simple geometry, you can tell how far away things are. And so this business we talked about 100 years ago, Henrietta Levitt, knowing that Sepians were good standard candles, but not knowing their true luminosity. And for that matter, any kind of star and its true luminosity. has really revolutionized, you know, quietly in some ways in the last couple of years,

our ability to calibrate the true luminosity of these objects. And so the work of we get to it about what's new, I'm going to tell you about is based on being able to calibrate luminosities much better with Gaia, particularly the what's called the third data release, which just came out last year. And that involves astronomy, of course. Let's see. The science are measuring the positions of things very carefully. Yeah, fantastic.

Yeah, I definitely want to get into that. And I want you to do one small favor, Adam, because we have a lot of people watching over 100 people watching live and asking. The one topic that they're most interested in is, can you mute your laptop's vibrations because they are getting a little bit motion sick? Let's see if we could do that. That would be great. Okay.

Thank you. Yeah, perfect. So Maya Benowitz, who is a longtime friend and supporter of the show, thank you, Maya. She is asking the question I think that's on everybody's mind, and maybe we will slowly transition to it now. Is there a consensus in the community about the Hubble tension? Today's result is, or this last week's result, is not specifically about the tension. It's about an exquisite measurement that you have done, which may be, if I'm not mistaken, the final, you know, measurement by the Hubble Space Telescope. And that of the Dahlant of this type of parameter,

the gold standard set of galaxies, or you call them mile markers or so forth. So first of all, is there a consensus or is that not really the case? I mean, I talked to a theorist yesterday and Aegis at NYU, and she was saying there's no consensus, at least from the theoretical perspective. So what's the current in the astronomy community? So the news release that we had was based on a very large study

that's taken a number of years where we've more than doubled the data set. And as I also mentioned, we've been using Gaia now to calibrate. And so we've gotten to one kilometer per second per megaparsec uncertainty. So that's really the big news is to get to 1.3% in the Hubble constant. Now, the answer we get, 73 is now 5 sigma higher than what you predict the value should be based on the classic microwave background. and the cosmological model. So, you know, 5 Sigma is pretty high.

You know, we normally say in science that we're comfortable once we're at 5 Sigma of not thinking of attributing this to just luck or, you know, being unfortunate or something like that. So, you know, in terms of being definitive, I would say that's about as definitive as we could be in an empirical sense or an absolute sense. Then, you know, you could look at other techniques, other ways of measuring, and in the late universe or the local universe, those values range from about 70 to 75. But I think a good way to summarize is there's no really precise measurement in the late universe that is coming in any lower than the cosmic microwave background. So they're all high. They're at different levels high, but they're all high.

and our result has the smallest uncertainty, and it's 5-sigma high. So I would say it's very difficult to look at this data and make a case that these two things are consistent. So in that sense, the tension's getting exacerbated. Yeah, so I would say, you know, people are in pretty wide agreement that this is a very significant issue that from the empirical side we need to take very seriously. I know my colleagues feel that way because they're putting in requests for telescope time and winning that and grants and whatnot. So, you know, that's our measure of when something is serious. But on the theoretical side, there's no consensus on what or how to explain this.

And when you make claims as you do that this is incredibly precise, is it the most precise that Hubble can do? And are there any other, is there any hope to improve things on the observational front, not the theoretical front of the observational? Yeah. So, you know, our rate limiting step is usually how many type 1A supernovae we can reach with Hubble, reach by meaning observe with sepheed variables or tip of the red giant branch or myras or any kind of star. And the reality is that there's only about one type 1A supernova that appears each year that is within that volume, within that range. And so what we've just published now is 42 supernovae that are basically the last. last 40 years worth, basically the entire history over which we've been observing with digital

tools. You know, you don't want to go back to the era of photographic plates. So now it's a waiting game. You just wait for new ones to appear at about once a year. And you can do the math. It's very difficult to imagine ever even doubling this data set in the lifetime of Hubble. So when you say, is this the best we can do? I mean, I'm sure technically there'll be, you know, improvements here and there. but, you know, the sort of big picture, how many type 1A supernovae we can collect and use for this measurement, you know, there's just no realistic way that Hubble that telescope is going to improve on this very much. Now, your advisor and my late great, your Ph.D. advisor and my late great friend, Andy Friedman, may he rest in peace, wonderful man, we miss him terribly here at ECSD. he used to tell me that the infrared had many benefits, that in the infrared type 1A's,

according to work that you and Bob and Andy and others had done, was significant. And I wonder if you can explain what that is, why that is, and if so, if there's anything in that web, this vaunted new instrument, can it say anything about type 1A supernovae that could improve upon even what you've done with Hubble? Right.

So when we talk about infrared versus optical, we're talking about how you observe the standard candle that you're looking at, whether it's a Cepid variable or a type 1a supernova. And as astronomers know, as you know very well, there's dust in the universe. And dust is very tricky stuff. Dust often messes up measurements. It dims the light of things we see, fools us into thinking they're further away than they really are. And so we try to correct or account for dust. because it generally reddens the light as well. But another powerful method is to observe in the near-infrared or even far-infrared where you basically see through the dust,

that the dust grains tend to be small enough and the wavelengths of light in the near-infrared or large enough that they essentially pass through the dust without any effect. And so for years with Hubble, the work I've been talking about, we've been observing the sepheids in the near-infrared, but not the supernovae in the near-imphor-red. Now, there's been a number of paintings.

papers in recent years that have taken our results on the sepians and applied supernova data in the near-imper-red from, from, as you mentioned, Andy Friedman and Bob Kirshner and others, and they generally get the same answer, whether we're in the optical or the near-imper-red. And so that part hasn't changed the story very much. Now, the James Webb Space Telescope is a telescope that operates exclusively pretty much in the infrared. It's a cold telescope. And so it will have a lot of power to, to look at objects in the infrared, and it has the capability to extend some techniques we use for distance measurements.

So I think it will certainly help on this overall quest to better understand the expansion rate of the universe. It's not obvious it's gonna give us a great improvement and precision, but I might test some of the ideas people have about some of the astrophysical objects being somehow weird or different. Very good. And getting a question from,

A man who goes by the name that I almost chose for my secondborn child. His name is Memes of Destruction. Not the Means of Destruction, the Memes of Destruction. Anyway, he asked, thank you so much, professors. Are there any updates or thoughts on Hawking Points? Now, I don't know if Adam is particularly up-to-date on Hawking points. Okay. Yeah, I have no updates on that.

Well, you know, Hawking was known for many things. and Sir Roger Penrose, who came up with this idea for Hawking Points, as a way to determine the after effects of previous aeons, or Eons, your fellow Nobel laureate, he used to say that making a bet with Stephen was the safest bet you could possibly make, because given enough time, he would always change his opinion. So you'd always win the bet.

So Hawking Points are these hypothesized leftover effects of black holes that are the only objects that can perhaps survive the conformal cyclic cosmological terminus, if you will, after trillions of years when nothing left is around, black holes endure, black holes and actually magnetic fields endure. And they claimed back in 2018 that Bicep was correct. We did detect primordial B modes, but they weren't from inflationary gravitational waves. As you know, Rogers finds that an anathema.

but instead we're from the aftershocks of these previous eons. Now, that allows me to pivot to my favorite explanation, as you know, for the Hubble Tension, which is a resolution via primordial magnetic fields. I've done some videos on this channel, including one called Hubble Tension Solve with Magnetic Fields. And we have a great conversation with Leibon Pogosian, and I've been in touch with his colleague, Carston. I always have trouble pronouncing Carston's name, and I know he's listening because he he hectares me when I make, when I make bad errors about his theory, Carlston, Jedansick, Jadamsic, hopefully he's on. Anyway, they think. Primordial, primordial magnetic fields look like as good a solution as any.

That's the, and I don't, I don't mean in a demeaning way. I mean, quite seriously, like the, you know, the idea, basically the easiest way, and there are no easy ways, but the easiest way to solve the Hubble tension is to change. the conditions of the universe before the cosmic microwave background radiation leaks out, basically make it different than the model in a way that generally makes recombination happen earlier, makes the sound horizon smaller. And my understanding is primordial magnetic fields would produce these in homogeneities that would clump up the universe faster earlier and cause that kind of condition. And so, you know, at a, you know, basic level, it could work. Now, the devil's in the detail, so, you know, I'll leave to you to tell us what the details work. Yeah, well, we're most interested in detecting this via what's called the

ferrette irritation of primordial polarization fields would be revealed by the existence of a deviation, so-called forbidden correlation. Sounds exciting, sounds sexy. But it's really just the non-vanishing so-called eB or T-B correlation functions. And we're very sensitive to that with instruments like the Simon's Observatory upcoming and current Simon's Array. So that is one of our primary goals. It's funny, Adam, because we proposed this, as you know, decades ago, starting with B-Sep to measure inflationary B modes. And that was basically a one-trick pony for Bicep, at least as I thought about it, back in 2001. But since then, we've really come upon things that could invalidate such closely held principles as Lorenzen variance symmetry, as cosmic parity violation and other exotic phenomena.

But along the way, I don't know philosophically if I've ever asked you this, but what is your, you do so much, you know, and I put in my first book, losing, you know, chapters seven, eight, and nine are dedicated to Adam. But, and chapter one of my newest book, Into the Impossible, is Adam, literally. But I put in, the thing that strikes me about you is very good taste. Not just, you know, which podcast you come on. But you have very good taste that you've cultivated. Are you still there? Uh-oh. I might have praised him too much.

Adam, are you still there? Let's see if we'll come back on. But I'll use this opportunity to praise him while hopefully he comes back on. Maybe his laptop bounced too much. But what I was going to say is that as an astrophysicist or as a scientist, you need to kind of be very selective

about what you choose to dedicate your finite amount of time on earth to, so to speak. And what Adam's been particularly good at is not only finding the right problem, but attacking its most interesting aspects with the greatest possible tenacity that one could envision. So here is Adam. Let's see if I can add him. Adam, can I add you? Are you there? Yeah. Awesome. Sorry. Yeah, I was praising you so much. Your head swelled. My head exploded. You were talking about my taste. Yeah, I was saying it's one thing to be technically competent,

but it's another thing to be goggly in pursuit of very subtle, very confusing and perplexing effects and consistently do that. And I have an anecdote in this book about how, you know, sitting behind you at some conference before we really got to know each other. I mean, we met in the 2000s, but we never really got to know. But I remember like just watching, you know, like this guy already has a Nobel Prize. He works his ass off. and he's got incredible hard problems that he has incredible taste to choose which part of your valuable time to dedicate to.

How did you cultivate that? Was that from Bob? Was that from just innately? Is that how you're wired? How would you communicate to my students? I guess I would say all of my mentors, all of my teachers have always seemed to have that good taste and always talked about, you know, what would be really important to do or what's really interesting. And I think, you know, in many ways, cosmology is that kind of pursuit overall. I mean, it's a very reductionist science.

We have very few, very big questions. And, you know, the key to cosmology is sort of keeping focused on the big picture, you know, the big questions. While, you know, you go up on a deep dive on the details of some object or some measurement, but never really falling in love with the object or the measurement, getting back to. the big picture, you know, reminding yourself, you know, these are tools to answer a question. It's not about the tools themselves. And so, you know, I feel like I always learned that from my mentors. Yeah, wonderful. So Maya is asking again, she's a theoretical physicist and a brilliant one at that. She's asking, can you comment on Wendy Friedman's tip of the red giant branch measurements of

the Hubble constant? What degeneracies does that break and which ones does it still suffer from? Right. So the tip of the red giant branch is a fainter standard candle than sepiates. It's a kind of a newer tool that people are using. And they have a much smaller sample because you can't reach out as far with those. However, there are about eight galaxies where we can observe distances with both the red giant branch and sepid variables. And this is in our paper. Where we have the measurements of the same places, they agree extremely well. And so to me, both techniques look good. But then as we increase our sample, our precision goes up. And although the results are consistent with tip of the red giant branch, they're more significant in terms of the inconsistency with the causing microwave background. Very good. Andy Oates, a long-term fan of the show and friend of the show, ask, would we get more precise measurements of the Hubble constant by placing multiple telescopes at different Lagrange point. So he's not satisfied with L2.

Could we do anything? I mean, Hubble is not in a Lagrange point. Hubble's in our backyard. Could you get anything from stereoscopic, or is that like Gaia's purview, so to speak? Well, I mean, yeah, in principle, if you could put two identical observatories very, very far apart, you could measure parallax, you know,

immediately. And that would be really cool to do. But to improve over what we get from the Earth as the Earth goes around the Sun, we get two astronomical units of diameter. And so you'd basically have to park one of those things over by Neptune or something to really make headway. So I would say Lagrange points don't really help in that regard. Right. Well, we've had proposals from Edward Witten recently to send spacecraft out to look for Planet 9. and that would take about 100 years and measure a time difference of less than a microsecond for our great-great-grandchildren to do.

So maybe it's not so outlandish. Throw on a couple of telescopes on that bad boy and get it out to way beyond Lagrange points. Let's see. Another gentleman who has a name that I also considered for my firstborn, his name is Zero Skull. First of all he says I'm a fanboy of Adam Reese. All right, fine. Well, you know, I have to give them as due. I have to be, you know, respectful to Adam, because I did beat him once in a very prestigious competition where I came in first and in a selection of potential Nobel Prize winners in 2005. And, you know, Adam proved me wrong, I suppose. But, but anyway, so yes, I am a fan boy, zero skull. But your second question is quite interesting. You're talking about, you know, the gravitational effects. And I taught my students this recently, Adam, gravitational measurements, time delay measurements of the Hubble constant, are those going to ever

yield anything of interest? Or where do we stand with that? First of all, could you describe the physics, look into your crystal ball of gravitational lensing and explain a little bit about time delays maybe? And then where could they possibly go? How competitive are they at all? Yeah. So this is a technique where you look at a very far away background object.

I'm going to say maybe it's a quasar or a galaxy. and there's some intervening galaxy or cluster or something that acts as a lens. And so it bends the light gravitationally. And so you may get multiple paths of light that are on their way to some angle that would not come back to you, except the bending due to the gravity brings the light back to you. So you might see multiple images. And you recognize that those multiple images are traveling different paths with different links. So if you have good telescopes and those objects vary in some way, you can measure the time delay between those paths.

And if you solve the whole problem, then you could ultimately get distances and ratios of distances and the Hubble constant. The trick or the challenge in many cases is knowing what that lens looks like, how mass is distributed in that lens, whether it's a galaxy or a cluster. We know it has a lot of dark matter, but we don't always know exactly how. how that matter is distributed. And so this is what I have to say in my field we call model dependent. You know, the answer often depends on the model that you have for how the matter is distributed. So, you know, to my way of looking at it, it's a little less direct, a little less empirical, and it has this model uncertainty. And so people have debated for a while now what the right form of that the mass distribution is. And so there's one group of the Holy Cow team, kind of a cool

hack of them, who said if you use the most conventional mass models, what are called power law or Navarro Franken White models, then they get a Hubble constant of 73 plus or minus two, very similar. If they don't use those or they open up that mass model uncertainty, then they could get anything from in the mid-60s to the mid-70s. So the answer they get is fairly degenerate with knowledge of this mass model. And so I think they continue to work on improving knowledge of the mass models. And so I think this pertains either to clusters or to individual galaxies. Ah, fascinating.

Thanks for that, Adam. So a reminder for those that are just tuning in now, we're getting close to about 200 people, watching on all different platforms. No pressure, Adam. So we're talking with Professor Adam Rays, Professor at Johns Hopkins. And also chapter one is his biggest accolade, I think, is that he's chapter one in my second book, which is called Into the Impossible. Think like a Nobel Prize winner.

If you like interviews like this, please do subscribe, but also leave a thumbs up on the little icon there. So I can get folks like Adam and hottest cutting edge stuff. We had Chef Dolman on last week talking about the exciting new results, imaging the black hole at the center. of our galaxy after the Titanic observations of M87. They followed up with Event Horizon. What's most interesting to you outside of what you're doing? Like, what do you do in your spare time? You know, what do you read in the nonfiction world of spare time, besides my books, of course?

In what am I interested in, like, for example, in science? Yes, in science, yeah. You know, I mean, certainly it's not something that I work on, but the quest to look for life around other planets is terribly interesting. So, you know, the whole field of exoplanets and looking at their atmospheres and trying to see if there's biosignatures is something that I certainly follow the kind of work that my colleagues do. So a question also kind of, you know, what do they call those? Human interest, you know, get to know the noblest. Behind you are several books.

I'm sure most of those are copies, multiple copies of mine that will help put my kids through graduate school. people want to know what else do you read what's on that bookshelf that impressive looking bookshelf over your i read a lot of history um i'm quite i i minored in in history uh at mit which i don't know if that counts but maybe uh and i've always been very interesting history and i'm in a book club on in history so uh anyway i read a lot of history books uh i think you learn a lot about the president future by reading history i don't think things change all that much and so uh if you wonder how things will turn out, read history. And you are a historian of the cosmos, right?

You're looking at these ancient photons looking out in your telescope. So now I want you to look in the future. So look into your crystal ball and tell me a little bit about where this field can be going. You're saying the bounds are sort of saturating from Hubble. Is it that we need more theoretical understanding? How much of the error bar comes from systematics in the theory of type 1A's? Right.

So I'll back up a little bit and say, we went through a period in the early 2000s, the 2000 aughts, where everything fit very well. In fact, we said, you know, cosmology was at a real consensus, and that was great. And in fact, many of us feel like we should have quit then because, you know, there were good feelings and everything was excellent. However, unfortunately, we kept pursuing more precise measurements over the entire field. you know, plank C&B observations, bicep, the kind of Hubble constant measurements I've been talking about, weak lensing measurements and maps, all kinds of techniques. And as often happens, the better the measurements get, the tighter the model is tested, we start to see tensions crop up in not just the Hubble constant, but, for example, another quantity known as Sigma 8, which is a measure of how

clumpy the universe is now. And again, sort of like we see with the Hubble constant, all of the measurements locally in the late universe done of how clumpy the universe is, shows it to be much smoother than you would predict based on the cosmic great background state of affairs and the cosmological model. So that's, you know, that's become kind of a second major tension. And so looking into my crystal ball, you know, we will continue to improve measurements. And so, maybe more tensions will come up, maybe really smart people will be able to explain how these relate to each other. Maybe we'll learn how to make measurements better and that that will be an important part of the story. So, you know, it's hard to look too far into the future, but I would say there's going to be better cosmic microwave background observations.

We're going to look for signals of what I would call for what people call pre-recombination new physics, which could show up in the fine structure of the constant weight grade background power spectrum. We're going to get observations of gravitational waves from LIGO and more advanced versions of LIGO that are going to give us an independent way to measure distances and the Hubble constant. They're going to be better weak lensing experiments from new observatories like Rubin and the Roman satellite

is going to launch and Euclid is going to launch. So there's a lot of data coming. And I expect we will learn some new things. Yeah, and on that topic, Chad Grosskopf, who's a member of the channel, one of my valued members of the Inti Impossible Family, he asked, can we use black holes expansion within a galaxy as a measure to help with the Kabul tension? I think I'm going to change it around and say, can LIGO or future incarnations, can they use

so-called standard sirens? Or will that never be as compatible? I mean, you're measuring things at the 1.3% precision level that is also accurate at that level. So yeah, can they ever do anything or is it just going to be like, okay, they're within five or 10% of what we're. You know, I'm optimistic. I think, you know, they're going to collect their first, I don't know, a dozen or so. And that will give us some interesting constraints on the Hubble constant. The problem becomes when they try to reach a comparable precision where we are, it turns out it's quite difficult to calibrate their detector to actually figure out, you know, how much strain, which is the quantity that they actually measure.

they actually see. And my understanding is that there are even quantum effects that become important in trying to calibrate it finally. And so, you know, I think they will have to develop new techniques to calibrate better. Look, I mean, we're in some ways 100 years ahead of them, you know, thanks to Henrietta Levitt. But, you know, they'll catch up. They'll make progress. I don't know, you know, how long it'll take to reach the precision we're at. But I think they will be able to weigh in on this problem in an interesting way, you know, hopefully in another five years or so. You kind of answered this from Jeremiah M. I'm asking what's most excited about in cosmology.

You also, you know, you covered life extraterrestrial life, et cetera. Do you think, by the way, Adam, do you think there's any, you know, kind of priors that one could put upon the search for extraterrestrial intelligence by the non-observation or no evidence for it? And I asked that because I've had on a lot of people, including winner of the Pulitzer Prize, Richard Powers, who's a wonderful writer. He wrote a book about astrobiology, which I think you'd love called Bewilderment. It's a fictional story about a father and son and dealing with death and all sorts of cool things, but also dealing with life and other planets.

And I said to him, I almost feel like, I don't think it's zero percent, but I think it's so incredibly rare that are such an incredibly low probability that life exists in the universe because I don't feel there's any evidence within our own solar system, despite the millions of years of billions of years of exchange between planets, and I usually have my meteorite collection nearby, but anyway, it goes by the dirty sounding name of Pantz, Pemia, which isn't dirty, don't worry, we won't get canceled, but the fact that we have failed to observe life on Mars and any other sites in our own solar system, at least that has to put some Bayesian limits on the facundity of the universe. Anyway, what do you feel, do you feel like it's just,

there's so much space that literally that there has to be life i mean you know i i think my view is the the common one held in our field which is um you know uh there's a near infinite if not infinite universe out there and so no matter how rare you make life it's going to be out there um and so that's you know to first order my general thinking i'm sure it is incredibly rare um it's just you know we have so many incredible uh rolls of the dice i guess you would say, that it's bound to happen. Now, what's interesting for us is if it's sort of detectable within our much more local sphere.

And I think that is the big question that nobody really does know the answer to that one. And so we will look, for example, with the James Webb Space Telescope, there's a number of programs that will begin to study the atmospheres of planets around other stars, and hopefully we'll teach us about the presence of that life. Speaking of life, Kenneth M is asking if the government has contacted great scientists like you or me to help in the investigative process. I am tangentially involved with your alma mater's famous search now called the Galileo Project, named after my favorite hero in astronomy, Galileo, Galilee, run by Avi Lowe, back at your alma mater. I want to ask you, I mean, I haven't been contacted. I'm not being cagy.

I'm just, no, I'm just kidding. I'm blinking. I have something in my eye. By aliens or by the government? Well, actually, I'd be more interested in the former, but the latter either. Yeah, either way. Neither. So now, do you think this is a subject that deserves, you know, the funding, the attention in Congress?

A lot of my viewers do like to speculate about this and like to hear. from honest to goodness scientists such as yourself that are working at the highest levels. You know, is this something that a serious scientist should pursue? You know, Avi gets a lot of kind of pushback. He's been a guest on the show many times. What do you think about this? Is it because of the prosthetic forehead problem that it's kind of ridiculed and not seen as a great vector to get tenure? Or do you feel like maybe you should spend one percent of your, you know, time on it or something?

So when I went to graduate school, I almost worked on SETI. I thought about doing it. And actually, my sister, my older sister said, you know, I don't really see how you're going to graduate and get a PhD if you don't detect anything. And I followed her advice. However, I must say, I do think that we should be working on this. We should be spending significant funding on it. It's the ultimate Hail Mary of all research. I cannot think of any discovery that would be more profound, that would be more impactful in the way we look at the universe,

to the way we look at each other, then the discovery of life around other planets. You know, I have kind of fantasy hope that it would have this kind of existential impact on people. You know, maybe it's being, you know, overly optimistic, but that it would cause people to sort of reset their perspectives in helpful ways. So on many different levels, I think it's, you know, it's the greatest quest of all. Yeah, I certainly agree. And that's, look, it's two people. and we have no fiduciary interest in this field. And yet we both find it interesting. I do, with love and respect, I push back.

I actually don't think it would be, I think it would be big news for a news cycle. I remember back in 1996 when you and I were grad students not far apart from one another. I was at Brown where I'm going back, and you were up at Harvard. And I remember there was a huge discovery. In fact, it made the White House lawn with Bill Clinton.

The Mars Rock found in Antarctica. And you know what, Adam, that's never been disconfirmed. That is still under active study, 30 years hence, and there's no telling where that was. So actually, I do get, as I often get, I often get, you know, oh, you're a part of Bicep. Like, you guys won the Nobel Prize, right? In other words, like the newspaper on the front page, and I've told Dennis Overby this and other people, you know, the story goes on page one. the discovery claim, as it did with Bicep, as it did with your supernova measurements. But if there's a retraction, it's on B-17 of the Saturday edition that nobody...

So nobody knows that, I mean, very few people, even in astronomy, know that Bicep was disconfirmed. I mean, a lot of people do, but some people come up to me in astronomy and say, wow, that's amazing. So I'm going to ask you, like, what, you know, to what degree should science sensationalism? And, you know, I was joking. I read about your discovery in the New York Post, you know, last... And just, as they say, just because it's in the New York Post doesn't mean it's wrong. But, you know, what extent should scientists be responsible for their, you know, stray findings and things that go astray? Should we keep a budget, you know, in hand for retractions as well as press conferences?

I think retractions are important. I understand that, you know, people don't cite errata as much as they cite regular papers and they generally don't put them in the newspaper. and I know quite a number of papers, specific ones, which have made a big claim, and then later on, either retracted or through even the refereeing, the peer review process changed quite dramatically. Unfortunately, it's just the nature of humans is to be excited to hear something really, really interesting

and then to find it much less interesting if it was retracted. But, you know, science overall is pretty good. I don't think we're led astray by these things very long. It might be that people on the street don't people on the street don't know something was retracted, but people in the field do know. You know, it doesn't deter us for too long. Yeah.

Very good. Well, Adam, if you have a few more minutes, I have a couple more questions from the audience. If that's okay? Sure. Okay. So Maya is asking another phenomenal question. God, Maya, I hope we meet someday. You're just full of ideas and questions.

She's not asking about local dynamics that could masquerade as a cosmological constant. And I want to pivot off that question and maybe turn it around a little bit. For years, there was interest in Mond, modified Newtonian dynamics as a solution for dark matter. And I'm wondering, inspired by her question, are there any analogs of Mon but for dark energy? Other explanations, if you will, that could explain via modifications of gravity, Newtonian, or otherwise, that could explain an account for, you know, the observations that you and your colleagues have been making. Your summer starts now with Memorial Day deals at the Home Depot. It's time to fire up summer cookouts with the next grill,

four-burner gas grill, on special buy for only $199. And entertain all season with the Hampton Bay West Grove seven-piece outdoor dining set for only $49. This Memorial Day get low prices guaranteed at the Home Depot. While supplies last, price invalid May 14th or May 27th. U.S. only exclusions apply. See Home Depot.com slash price match for details. Right. So to be clear, when we talk about any of the things we talk about, the accelerating expansion, the Hubble tension, everything, it's all based on assuming Einstein's general relativity works and that we can use the universe as a laboratory following the rules of general relativity. And so, you know, we would say, well, general relativity isn't right. All bets are off on these measurements and in the interpretations. And so, you know, we're always open to a new,

idea for what gravity could be. Now before I get flooded with tons of messages and and papers or whatnot, the it is very difficult. People have always struggled to come up with an alternative to general relativity that actually is not ruled out inside the solar system or on earth or many other things. And you know, this is the difference between, you know, scientists and in some cases, you know, armchair scientists is they have an idea that's great, but you got to check it first and see if it's already ruled out. And as I said, all of them are. And so, you know, the gauntlet is really thrown down by the universe in terms of coming up with an alternative. However, you know, having said that, we don't have a quantized

theory of gravity. We don't know how to unite general relativity with quantum theory, the, you know, physics of large and small. So there is reason to believe that there is still more to understand about gravity. And so I think it's a very active area of research. Yeah. So one last question for the audience before we break, and it has to do with sacred cows. And I guess the question I could be summarizing it, maybe with some discretion on my part, if the question is by Craig Dean, is dark energy a sacred cow? In other words, has it reached a level of originally when you put this out in the 90s, you and your colleagues, it was considered exactly the opposite. We didn't expect it. We thought Einstein was correct. The last

where it took tremendous courage for you and your colleagues to that. But now it's become the standard model. In fact, Barbara Ryden's wonderful book that I use is called, calls it the benchmark model and it's, and it's phenomenal. So I wonder though, you know, is it possible that something could be almost like too successful? In other words, if you say that this is, yeah, go ahead. Right. Or that we maybe, or that we cling to it in some way, that we say, well, there's got to be dark energy, so I'm not open to other possibilities. You know, my experience is scientists are much more open than people in many other fields. You know, we grew up with this idea that we have models that we're testing and falsifying,

and we've seen through the history of science, this is a very successful process. So it's okay if we falsify dark energy or dark matter or anything. But we still have to explain the evidence that led us to believe in them. So, you know, in the case of my colleagues and I, what we discovered was not so much dark energy as we discovered that the expansion of the universe is speeding up, that it's accelerating. If there's another way to explain that without dark energy, you know, a modification to gravity or something, I think we'd be very open to that. I certainly know I would be. And I just, I'm very confident in the science method that, you know, if the data is better for an alternative hypothesis

than the ones that we have, then that will win out. It always has. So when we talked a couple years ago in the interview that made the opening chapter of my second book into The Impossible, we talked about something that I call the academic hunger games, which is that you have all these hurdles to get up to and get through, and then finally you might get a faculty job. And if you get a faculty job, you might get tenure. You might win some prizes and get citations and so forth. And I asked you, do you ever feel like the game is broken? And you said, yes, I think it's not a great job. great scheme. I'm lucky that I did not feel compelled by that scheme. And that's something that's parenthetically always impressed me about you. You've never been driven. Like the Nobel Prize for you is just, it was a great thing, obviously, but it wasn't like what you set off to do since you were a kid, unlike some people, present company. But my question now

involves something that Brian Schmidt and your fellow laureate, and I talked about, which is that he viewed with regret. And he was a postdoc, if I'm not mistaken, while you were a student. And You guys were incredibly tightly, you know, working close together. And you had these competitors on the Supernova Cosmology Project led by Saul, Perlmoner, who has yet to reply to an email, let alone come on the show, but hopefully he will someday. But Saul, you know, and his group, you know, Saul's a very mild-mannered appearing person, but from what I heard from Alex Dolopenko and from Brian was that they regretted most kind of the, what Brian called toxicity, that there was kind of a message communicated to,

young people like you, that, you know, science is this incredibly cut-through, as I say, the academic hunger games prevailed even within a collaboration. How did you overcome it? And you got to, it's like, you know, children of divorce are more likely to get divorced, I'm told. But, you know, how did you overcome it? And what advice do you give to mentors and other people like me and my audience to kind of, you know, show the right side of science as you've been doing so? Yeah, you know, that's a good question. It's a big question. You know, I'm going to kind of reframe this as, you know, the role of competitiveness that shows up in science.

And is it healthy? Is it unhealthy? You know, lots of it is unhealthy. But on the other hand, just as I described, I mean, science is always this ultimate competition between ideas, between data. You know, in the case of these two teams making this discovery, it was important to people to see two teams. you know, reaching similar conclusions. So, you know, I would say that, you know, it has positives and negatives, but, you know, you have to ultimately keep it in check because, you know, who are we competing with the universe? I mean, you know, the ultimate competition here is, you know, the universe sort of guard secrets doesn't make things obvious as far as we can tell. And, you know,

we're competing to try to figure out those things. And, you know, the best science ultimately builds on other science. So, you know, I look at my, quote, competitors' papers to learn things and to learn, you know, what should I do better? What should I do differently? What did they find from this experiment? So, you know, I think it just takes scientists recognizing, hey, the competition is out there. It's in the universe, you know, the challenges are out there. Yeah, I mean, it's, you know, we may have a little bit of local competition to see, you know, do we agree, do we disagree? but you don't want to lose perspective. Otherwise, you know, the science will lose, you will lose, and you'll be very unhappy.

Well, Adamona, thank you so much for coming on the show. Anything you want to mention or something coming up for you? Looking forward to getting back to conferences and so forth this summer. Sure. And I'm looking forward to the James Webb Space Telescope. Everybody should look forward to July is when I expect we will see first images. That's phenomenal. Yes.

We've had a couple of guests on, Hakeem O'Shea. and others on the show and talked about that. And then, Dadley, we'll have more results and great guests coming on. So thank you so much. I had John Mather on and got to get him back on as well. Because it's great to have scientists that do outreach and communicate with the public. And that's what I try to do on this channel. I hope you all subscribe and follow Adam and myself and look forward to many, many cool episodes coming up.

Jarant Lewis is coming on the podcast, Anna EGis, who's got an interesting model called called the bouncing cosmological model, kind of competitor to inflation. She's a wonderful guest recorded with her recently. And Adam, thank you so much, a short notice. It's late in the night getting out there where you are. I do hope we can meet again in person. It's been too long. Yeah.

Sounds good. Thank you, my friend. Bye, bye. Well, that's a wrap on this episode of the Into the Impossible podcast. Special thanks to Dr. Adam Reese, my friend, and sometimes subject of my books. He is really an amazing individual, isn't he? And he's contributing, never resting on his Nobel laureate laurels like he could. And instead, always endeavoring to go deeper into the cosmos.

I really love his style, as we talked about. And I hope if you like the style or even if you have some criticism, I don't mind having criticism as well. So I would encourage you to leave me a review, constellation and asterism of stars on Spotify, Apple, Audible. You can do it anywhere you get this podcast. But on Apple Podcast, you can also leave a little blurb and say what you like about this podcast or what you'd like me to do better in the future.

So I want to read a recent review that I received from someone by the name of The Meaning Code. It's called Always Gracious but Diggs Deep. That's the title. Brian Keating uses his Into the Impossible Podcast in the best possible way, dialogue with great minds and digging deep for the implications of what they say. I always learned something new. So we've reached over 510 reviews worldwide, over 379 in the USA alone.

So please do leave you that. It helps me improve what I'm trying to do. And it's really thanks to you guys. So for now, I thank you. And until next time, have a magical week and keep going into the impossible. Yamava Resort and Casino at San Manuel is California's number one entertainment destination for today's superstars. Catch the Jonas Brothers return to the Yamava Theater stage on April 30th,

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