The Supermassive Podcast - 52: Voyager: Where no-one has gone before...

Episode Date: April 29, 2024

Two of the most remarkable spacecraft ever launched are the stars of this month’s episode: Voyager 1 and Voyager 2. Izzie and Dr Becky talk to Dr Jamie Rankin, the mission’s current Deputy project... scientist, and editor Richard gets to chat to Ann Druyan, the original Creative Director of the Golden Record project, who worked alongside her husband Carl Sagan. The Supermassive Podcast is a Boffin Media production for the Royal Astronomical Society. The producers are Izzie Clarke and Richard Hollingham. 

Transcript
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Starting point is 00:00:00 Like even I, looking at it, going, that can't be real. The major goal was definitely to see the giant planets. And it was this amazing pace of discovery, finding things, you know, possibly deep oceans on Europa, you know, volcanoes on Io, all that kind of stuff. Why have two spacecraft? Why not just have one? Hello, welcome to the Supermassive podcast from the Royal Astronomical Society with me, science journalist Izzy Clark and astrophysicist Dr Becky Smethurst. That's me. Last month it was all about interstellar space. So this month, inspired by listener Suraj, we're going to feature the most famous spacecraft to leave the solar system, Voyager 1 and 2.
Starting point is 00:00:44 How have they shaped our understanding of the solar system and what lies beyond and how are they getting on as well? We'll be speaking with Deputy Project Scientist of the Voyager mission, Dr. Jamie Rankin, to cover the basics, plus, and this is very exciting, Andrian, Creative Director of NASA's Voyager Interstellar Message Project, who worked with her husband, Carl Sagan, to produce the golden records attached to both Voyager 1 and Voyager 2, will be here as well. I'm so excited. And obviously, the biggest of our stellar lineup is Robert Massey,
Starting point is 00:01:17 the deputy director of the Royal Astronomical Society. Highly debatable there. It depends on your definition of biggest. Was she just giving a deep... True, if we did it by weight, possibly. Oh, no, this has got mean. I didn't mean that. It's still really OK.
Starting point is 00:01:31 But, Robert, what does the Voyager mission mean to you? Well, as a man in my 50s who's not sensitive to these kind of terrible attacks, no, it almost matches my interest in the universe we live in. So I was thinking about this and I thought it's one of my earliest memories of space exploration because I'm too young for Apollo. I was born after Apollo 11. Don't remember any of them at the time. And I don't remember the launch of the Voyager probes because I was only seven. But I do remember that when they got to Jupiter and Saturn and then for Voyager to Eurus and Neptune, because you had these amazing images, they were processed so much better, they look so much sharper than the earlier Pioneer probes
Starting point is 00:02:07 that had just gone to Jupiter and Saturn. And it was this amazing pace of discovery, finding things, you know, possibly deep oceans on Europa, you know, volcanoes on Io, all that kind of stuff, details the ring system. And you have to remember as well that this was a time when there wasn't a lot of planetary exploration going on. The Apollo program had long since come to an end
Starting point is 00:02:25 and it was basically the Russians doing stuff with space stations. So it was really, really exciting. They really got a lot of attention. And it also took advantage of this unusual time when the outer planets were lined up in such a way, so everything from Jupiter through to Neptune, to allow a grand tour whereby you could send a probe to Jupiter and use its gravity to accelerate the spacecraft onto Saturn
Starting point is 00:02:47 and then Saturn onto Uranus and Uranus onto Neptune. So that only happens about every 175 years. So the space scientists in the 60s and 70s were really, really keen to exploit it. Cheers, Robert. We'll catch up with you later in the show for some more questions and some stargazing. The Voyager missions blasted into space 46 years ago voyager 2 went first in august 1977 followed by voyager 1 a few weeks later the mission itself was originally intended to last five years and focus on just jupiter and saturn but five years became 12 and
Starting point is 00:03:19 they just kept on going and going and bringing with them a close-up of all the outer planets 48 moons, and a better understanding of these planets' ring systems and their magnetic fields. So how important is this mission and where are they now? Over to Dr. Jamie Rankin, who's Voyager's current deputy project scientist. The major goal was definitely to see the giant planets. Even to this day, the flybys of Uranus and Neptune, those are the only flybys by a spacecraft. And then after the main mission part was over, they basically set their sights on going as far as they could and seeing where the boundaries of
Starting point is 00:03:58 our solar system are and how it interacts with the interstellar medium. That mission started in the early 90s after they turned off the cameras and took the infamous pale blue dot photo. They went into an interstellar mission phase and they didn't know what they would find. They didn't know where the boundaries were and they just wanted to keep on going to see what we could see. And you mentioned there the pale blue dot image. It's iconic. I know that word is overused, but it really is. So if anyone hasn't seen that, what is that image? So that image was taken by Voyager 1. And it was amongst the last images that they took before they turned off the cameras
Starting point is 00:04:40 because it was at such a far away distance that not enough photons were reaching those cameras to actually make sense of things. So as their near last images that they were taking, they looked back, they took this picture that was basically a part of the family portrait where they were trying to gather pictures of kind of each of the planet's images of the solar system. And the pale blue dot itself is the photograph that was taken of earth and it was taken on valentine's day which is a fitting day to take that 1990 and there's this really just small speck it given gave a first time a a real glimpse of how small we are uh in this place of the universe in this like new way
Starting point is 00:05:26 that hadn't been done before. Why have two spacecraft? Why not just have one? The once in 176 year planetary alignment caused people to want to really make this work so they had two spacecraft but as far as exploring space it's been advantageous for many reasons. The two Voyagers launched slightly different, going different speeds, different times, slightly different times of their planetary flybys. And that also has allowed them to be spaced apart. And so, for example, as an event from the sun might overtake the Voyager spacecraft, it's hugely advantageous to see one in one spacecraft and then see one in the other and get two blips in time of the same event, for example. They fare differently through the history.
Starting point is 00:06:18 There's a slightly differing set of current operational instruments. So the Voyager 1 spacecraft can measure magnetic fields and cosmic rays, and Voyager 2 can do that too. That's common between them. And then there's a slight difference in how the radio instruments operate. It's a more fully functional radio instrument on Voyager 1. And there's some measurements they have on Voyager 2 as well, but not the full frequency spectrograms.
Starting point is 00:06:45 And then the plasma instrument on Voyager 1 doesn't work because it felled somewhere around the Saturn flyby, I believe. But the Voyager 2 plasma instrument does work and it's been taking really valuable measurements. So people have been very excited. And just even with these little small differences, even though all these same instruments are on board the operational differences of which one survived through history you know has gotten people very excited about both spacecraft and having having this really nice full suite working on both spacecraft so let's get on to some of the discoveries what would you say have been some of the biggest findings from the mission? So definitely these planetary flybys were amazing.
Starting point is 00:07:31 All the information we have on Uranus, Neptune is just extraordinary because that was the only to date spacecraft flybys of my Voyager 2 to those two planets. So everything from the side tilt, the differences between those planets and the other gas giants of Saturn and Jupiter caused us to think about those bodies in different ways. When they did the flyby of Jupiter, they saw on this tiny moon, Io, a lump coming out the side and they saw a plume of gas. And at first, they thought that was maybe a smudge on the image. They didn't know what this was. And they figured out that that was the first volcano on any body not on Earth that they had ever seen. And now we know there's many, many, many volcanoes on that little moon. There's volcanoes in other places as well, but that was
Starting point is 00:08:26 surprising. But I think in a bigger picture sense, the more recent data is equally as extraordinary, which is figuring out how far does our solar system extend and how far do the materials of our sun extend? Nobody knew where those boundaries were, But we also discovered what is it that these materials of our sun are protecting us from. So interstellar space has all this radiation out there in the form of what they call cosmic rays. That's just particles that are energized by the explosions of supernova and other processes. And it turns out that 85% of the flux of cosmic rays in interstellar space gets shielded by our sun's materials by the time it reaches Earth.
Starting point is 00:09:14 And so it's worth asking the question that without our heliosphere and without this bubble of material that our sun forms that evidently seems to be protecting us, would life exist without this uh and that's that's a big question absolutely huge question to be quite honest right so let's talk about that just a little bit more where are they now all right so voyager one is the farthest man-made object from our solar system and it is 22 and a half light hours away. So that means that if we were to send signal and wait for that to respond, Voyager 1 to send its response,
Starting point is 00:09:57 that would take just under two days to arrive back at us. And it is at roughly 160 astronomical units away. And that's roughly more than the distance from here to Pluto, past our solar system's boundary of the helipause. And Voyager 2, it crossed the helipause boundary a little later. That's around 135 astronomical units away. And what information are they collecting and how can you still use that data today? So they're not taking pictures of planets anymore. But they are measuring all sorts of things about the, I guess, electrifying elements of space, you could say. So there's magnetic fields that can be measured. There's radio waves that can be measured. There's particles, cosmic rays, this radiation, basically the environments, a lot of the environments of the plasma itself that makes up the interstellar medium. And what we discovered
Starting point is 00:11:05 plasma itself that makes up the interstellar medium. And what we discovered once the Voyagers reached interstellar space is how quiet it is out there compared to inside our solar system, compared to outside. Is there a cutoff? Do we know how long or how far the Voyagers will keep going? Oh, that's a good question. I think there's two things that are fascinating here. First thing is the scientific question of how far will the sun's influence still be felt in the interstellar medium? And we don't know yet. There's no signs of that decaying away. And we're hoping that the Voyagers can go as far as possible so we can see if there is some change where the sun's influence isn't felt as much. Another thing is these are 46-year-old spacecraft. I don't think anybody really expected them to go that long, so we're kind of surprised by that. I mean, these continual science discoveries are incredible on the one hand, but on the other hand, it's kind of groundbreaking
Starting point is 00:12:05 in terms of how long can a spacecraft operate? We're very hopeful, maybe just three years, we'll have a 50 years, you know, spacecraft. Yeah, that'd be incredible. And I think that's also
Starting point is 00:12:16 just a testimony to so much hard work and diligence from the team in keeping it operating, you know, over these many decades, multi-generationally. Thank you to Dr. Jamie Rankin. So Becky, let's go back to some of those Voyager discoveries. You know, how important were they and what were some of those most transformative ones, I suppose? Yeah, I mean, it's almost easier to list like the things that we, you know, didn't change our understanding from Voyager that it did change, right? I think the big ones that
Starting point is 00:12:49 stand out for me in terms of discoveries is just all the sort of moons and rings that it detected around the gas giant planets that we just didn't know were there. Jupiter, it detected two new moons in a thin ring, Saturn, five new moons, and also a new ring of Saturn, the G ring as well, that we didn't know was there. And then Uranus, it discovered 10 new moons, plus like two rings around Uranus. And then at Neptune, five moons and four rings and Neptune's great dark spot. You know, these features that we're so sort of used to seeing in images of Neptune. I feel like especially for Uranus and Neptune, they were just these sort of fuzzy blue discs before that you know just these like round shapes in the sky and voyager really sort of gave them features and personalities you
Starting point is 00:13:31 know before that we just didn't have i think the biggest one for me is like volcanoes on io i can't even imagine what living through that discovery must have been like for the scientists and the weird surface that it has and discovering that it is the most geologically active place in the solar system because like it's something that we just associate with earth so much right and everything else looks like these sort of static blobs in the sky it's really like yeah no and i loved it that jane when jamie was saying that when they first saw that plume they thought it was a smudge on the image they were like yeah is that is that right like yeah that that first moment must have been incredible yeah exactly and then also like i mean continuing on this path of like oh you know
Starting point is 00:14:12 realizing earth's not that special again um they sort of investigated titan um one of saturn's moons as well this thick atmosphere that they found there that was like 90 nitrogen about 1.6 times the atmospheric pressure of Earth at sea level, right? All of a sudden, it becomes somewhere else in the solar system, you might be able to get liquid on the surface. And having liquid on a surface, again, seems like so much that is just so like Earth's, like that's Earth's characteristic. What are you doing? Like, you know, stealing that glory so it yeah i think uranus and neptune though were really were the most sort of transformative in terms of our understanding
Starting point is 00:14:50 though like voyager 2 revealed that neptune was way more active than we ever thought like 1100 kilometers a second winds on neptune an atmosphere made completely of hydrogen rather than the methane that we necessarily thought is the methane that gives it its color, but it is still mostly hydrogen. And now, of course, it's also transforming our understanding of interstellar space as well, right? With it, with its finally leaving and actually recording what it found. So I think, you know, I hope discoveries are still coming from Voyager missions in the future too. I mean, there's so much to go through there. Do you have a favorite favorite one I have a feeling it might be attached to a certain planet I think you might be right because I think there's only one right
Starting point is 00:15:31 answer and it is Saturn's hexagon right like yeah fair I mean it's a good one it's a good one I mean for those who haven't seen this you haven't heard me harp on about it constantly there is a storm raging at saturn's north pole that is hexagon in shape which was discovered by voyager one when it flew past saturn like even i looking at it go no that's not that can't be real i can't imagine you literally just put your hands on your head like to be like no like can you imagine what also like you know people thought when they first saw that image like everything in the universe is is rounded right nature likes to make things round so finding hard angles is just weird and it's taken like decades for us to figure out like what is actually
Starting point is 00:16:17 going on it was a team from the university of oxford that managed to figure out it might be something to do with standing waves set up by winds in the atmosphere of Saturn where if you've got two winds going in opposite directions they can interact to give you this hexagonal shape which is crazy and as of this week you know at the point of recording anything can happen from here on in but yeah communications with voyager one have just come back online it's sort of been a bit iffy over a period of time so what happened there yeah it sort of started sending back gibberish in november 2023 last year um so for about six months it's been i mean it's been operating fine it's been responding to any like commands that were sent to it but any like scientific data or engineering data that was sent back just didn't make any sense it was just complete gibberish and this is a vintage spacecraft that we're talking
Starting point is 00:17:15 about now that we hope will last as long as possible but we know well you know we'll eventually fail due to age or just a lack of power more likely. Thankfully, that was not this day. The team at NASA figured out essentially that the fail was due to a single chip failure in one of the boards on Voyager. So that caused some of the onboard computer memory to get corrupted. And so because they couldn't actually replace the chip that failed, they had to do this workaround where they essentially patched the software to other bits of the memory on the computer so that it could run the same again, but then they had to get all of those patches
Starting point is 00:17:52 to then communicate with each other and actually work as it used to. So now having done that, we are getting comms back from Voyager 1 and now they still have to test it to make sure that all of those patches that they did doesn't affect any of the scientific data that they get back from it so they've got a few more weeks of testing to go but it's just really promising news that
Starting point is 00:18:12 you know we've got comms back with it and also just a reminder that the engineers and the computer scientists at NASA are just incredible problem solvers that they can also do this with a 53 year old bit of kit as well yeah i mean it that does just blow my mind a little bit it's just incredible now the voyager spacecrafts are packed with lots of different instruments you know you've got an imaging system a radio science system a cosmic ray system and a magnetometer just to name a few. But amongst them, placed on the side of each craft is a 12-inch gold-plated copper record. These are the golden records containing sounds and images selected to show the diversity of life and culture
Starting point is 00:18:57 on Earth for any potential spacefarers that may just find them. Andrew Yuen was the creative director of the project, working alongside her husband, Carl Sagan. And I'm excited to say that our editor, Richard Hollingham, spoke to her to find out how they were made. Anne, thank you so much for joining us on the Supermassive podcast. My first question, really, and you would have been asked this a lot, what did you hope to convey with the sounds of Earth on the discs? You know, the whole idea of the disc with the video and the images.
Starting point is 00:19:33 I mean, what was the purpose, the thinking behind it? Well, Richard, it's great to be with you. And I've had that question before, but I find that as I think about it more deeply over the decades, I find a kind of new understanding. So I'm glad you asked me. What we hoped to achieve was to convey to the beings of a very distant future and very different worlds, worlds, what it was like to be alive in the spring of 1977, to be young and aware of the dangers that our planet faced. Even then, we were just beginning to really take seriously the prospect of climate change. We were even more concerned about the 60,000 nuclear weapons that essentially put
Starting point is 00:20:29 everyone on Earth in a kind of hostage drama. And we knew that in the best of circumstances, even if we don't wreck our own future and we endure, the fact is that even the stars die, And we endure. The fact is, is that even the stars die, even our sun will someday change sufficiently so as to devour the Earth. And we were thinking in those great big timescales of hundreds of millions, even billions of years. which was only supposed to last for five years, is now still functioning almost 50 years into the project. Of course, we couldn't know that back then, but we had a lot of confidence in the engineers at the Jet Propulsion Laboratory working for NASA in California. And so we wanted to create a lasting document to bear witness with our eyes and ears and hearts and brains to what it was like to be fully alive. And we didn't want it to be just a kind of message from the imperial wizards who had created the spacecraft. We wanted to reflect that planetary perspective
Starting point is 00:21:47 that Carl Sagan was so passionately involved in presenting to the planet. And so we wanted to show the diversity of the ways of being alive, both the transcultural diversity, but also the idea of what the other life forms with whom we've yet to make contact on this planet were saying and singing and calling to each other. Was it a hard sell to the engineers at NASA? You go up to them and say, well, we're going to stick these quite weighty gold records on the side of your lovely spacecraft. Or was it thought about from the beginning? Was it always going to be part of the mission that these were going to be our ambassadors, if you like, from Earth to the cosmos? Well, this mission of exploration was taking advantage of a rare planetary configuration
Starting point is 00:22:48 that only happens once every 175 years. So the last time it happened was the presidency of Thomas Jefferson. So we had this feeling of this window. And because of the success of the Pioneer plaques that Carl Sagan, Frank Drake, and Linda Salzman Sagan had created for the Pioneer spacecraft, NASA actually approached Carl in the person of the wonderful John Cassani and invited Carl and Frank to do something for this new mission. And, of course, Carl and Frank immediately started thinking, how can we make this a message of greater density of information? And I think it was Frank, the wonderful Frank Drake, who had the idea to make it a kind of phonograph record.
Starting point is 00:23:49 And that was another of my questions because that's quite clever because anyone can play a record. As we see, audio technologies have come and gone. We've gone through tape and things like mini discs and CDs. People are still playing records. And you've got instructions as well to anyone who finds these of how to play these records. Yes, and a stylus is included to actually play the records. So, you know, we were trying to anticipate whatever the possible needs
Starting point is 00:24:18 might be of beings whose evolutionary story is so different from ours. And we had enough respect for nature to know that we couldn't really imagine them. All of us knew we could never have imagined an elephant or a giraffe. And so, of course, we couldn't imagine what these extraterrestrials would do. But we did know that the only way they're going to be able to find the spacecraft and then the record is if they're spacefaring beings. And so we immediately assumed that if they had conquered the challenge of interstellar flight, that they would have the wherewithal to figure this out. Well, I mean, you can see all the contents listed on the Voyager pages of the JPL website. I mean, it's an extraordinary list and to have got that
Starting point is 00:25:10 down onto a record. What struck me just looking at the list before we spoke was it's quite optimistic, I felt. I mean, you mentioned climate change and nuclear war, but actually, I felt the images, and certainly the music, it's a positive reflection of Earth. I mean, was that a deliberate choice? Because you could, you know, you could fill it with war, or you could have, you know, just the negative things, the awful things that humans do to each other. But actually, I felt it was quite a positive message. Richard, you put your finger on what was the topic of the most heated debate, because the question was, is this going to be a merely social gesture? When you meet someone,
Starting point is 00:25:57 as Carl said, you usually don't air your dirty laundry at that moment, you want to make a good impression. And because so much is open to misinterpretation, you know, we felt we had to tread carefully. But there were those of us who felt fervently that Cambodia, Auschwitz, the Belgian Congo, that these, the United States, the history of the murder of the Native Americans, the enslavement of people dragged from Africa and brutalized for hundreds of years. There's so many examples of our gravest human failings, our gravest failures as a species. And that's what we talked about the most. And in the end, we decided that what we wanted to do was to send a message of the things we took pride in, the things we loved about our planet. And one of the things that Carl said that was so profound is that the spacecraft itself would say, would speak volumes about us. This is a species in the adolescence of its
Starting point is 00:27:16 technological development, making its first baby steps into the Milky Way galaxy. And so that would speak volumes about us. And I also had another opportunity in the sequence of my meditation, the hour-long meditation, which consisted of my brainwaves and my heart sense, to tell something through my thoughts of the predicaments that we find ourselves in. That's so fascinating. You know, these spacecraft, again, you can check the exact distances on the JPL website, but 15 billion miles away, Voyager 1, 12 billion miles away, Voyager 2. But they've got a long way to go before they may ever encounter anyone. I wondered if it matters because creating the art is almost as important as them actually
Starting point is 00:28:13 ever being read or ever being discovered, or do you feel they will one day be discovered? The chances in the vastness of a space, you know, the voyagers have been on their way, moving at 38,000, 40,000 miles an hour for 47 years. And still, they're not even a full light day away from us, let alone a light year. Think of how vast the galaxy is. Think of how vast the universe is with billions of galaxies. We really are those little tiny mites on a pale blue dot. And so the chances are slim. But as Carl would say, anything over zero is worth doing.
Starting point is 00:29:10 So, you know, these Voyagers will circumnavigate the Milky Way galaxy perhaps a dozen times before they are completely destroyed and the records that they carry are ruined. And so, you know, anything can happen in that period of time. Thank you to Andrew. And I just, I'm still thrilled that she agreed to come with this podcast, to be honest. So win for us. And I'm very jealous that it was Richard that got to talk to us. Yeah, I know. I was supposed to be me and I had a work trip that scuffled our plans. Thank you, Richard. Thank you, Richard.
Starting point is 00:29:50 This is the Supermassive podcast from the Royal Astronomical Society with me, astrophysicist Dr. Becky Smethurst and science journalist Izzy Clark. Before we get on to questions about the Voyager missions, we should really talk about the eclipse and the jealousy that we're all trying to suppress here that Richard actually got to see it. You've had a great time. There's a lot of jealousy coming my way.
Starting point is 00:30:15 How was it? Was it absolutely amazing? It was amazing. I have to say we were incredibly lucky because you would not pick Northwest Rural Pennsylvania as a destination to see this particular eclipse. And I really feel for the people who booked their accommodation and booked their flights and everything years and years in advance, as people do for eclipses.
Starting point is 00:30:36 And then we just randomly turn up because we happen to be in Pennsylvania. So we were at this state park,imer tuning state park in pennsylvania we only actually chose where we're going to go on the morning of the eclipse it's really just on the ohio border up near up near erie and it was just a beautiful location there were families fishermen people having picnics but it was cloudy i mean it was really cloudy. And we just thought, well, it's going to go dark and at least we'll experience it in America in a rural setting. It's a lovely location. But as the day went on, the clouds started to clear and we started to get more and more optimistic. And by the time of the eclipse, it was completely clear. so we just saw every part of it so the sun gradually being sort
Starting point is 00:31:26 of eaten away by by the moon that that toenail moon uh just before when i was watching it i was thinking oh there's the toenail moon and i you know really hated myself for that you're welcome and then you know when we got totality because you know people were interested in it was really interesting being there with with non-astronomers because people were sort of watching put occasionally putting their you know solar glasses on which have been given out locally um looking up at the the sun kind of being eaten away and they were sort of yeah, yeah, that's quite interesting. It's quite cool. But when the totality came,
Starting point is 00:32:10 there was like this, whoa, right away across the park. You could hear it across the lake. It was incredible. And we were, you know, just so lucky to see it completely clear, see those prominences as well. I mean, it was a spectacular eclipse. So many of them, wasn't it? Yeah, so just very lucky.
Starting point is 00:32:28 I didn't use my phone during it. I just took it in. Enjoyed the moment. Yeah, absolutely. So, yeah, I mean, if you've not seen the eclipse, I thoroughly recommend it. I also recommend Pennsylvania State Parks because they're great. Amazing if you can do two in one.
Starting point is 00:32:45 I mean it sounds a little bit more glamorous than me watching it on the sofa on iPlayer. I was like this will do, this is fine. Well I guess if you recommended eclipses, Richard, I guess we should chat about when the next ones are. Well, I've started to get the bug. That was my third. I mean, but I've only seen two because the first one was in the UK.
Starting point is 00:33:14 So I've seen the last two US ones and we're already looking into Egypt, but everything already is booked up. You know, when you looked anywhere across the next eclipse. Oh, I haven't even thought that like bookings would have opened yet and stuff like that for flights especially because i was looking because i mean for those in the u.s they've almost got used to having one every like seven years now but sad to say for listeners in the u.s the the next one that actually crosses the lower 48 again
Starting point is 00:33:37 is in 2045 so you've got a bit of a time to wait you You might have to travel. I've got my eye on the 2026 eclipse that comes across Northern Spain, but also goes across Reykjavik in Iceland. And I think most people are like, oh, you know, Iceland, not exactly the best weather, but I think it's a high risk, high reward situation because there is a chance that you could see the aurora during totality.
Starting point is 00:34:01 Oh, wow. Which would be the most incredible sight ever right and so i'm kind of like i could go to northern spain but at the same time do i want to risk the aurora yes i think so group trip to recuivite yeah yeah we need we need we definitely need a supermassive trip to that as you said there's another one in 2027 that crosses southern Spain, North Africa and the Arabian Peninsula. But then there's also one in July 2028 that crosses Australia,
Starting point is 00:34:32 for any Australian listeners out there. But it goes straight over Sydney. Like totality passes over like the Opera House. Oh, wow. Which is just, I mean, come on. I've got to go to that one. That's going to be the biggest Instagram ever isn't it yeah we're looking at the 2027 eclipse across egypt and already hotels are all booked up so um that's crazy yeah it is so flights don't open but i mean i guess you could
Starting point is 00:35:00 take the risk and you know from my experience of, well, I've drawn a different experience. The Eurovision Song Contest. So we didn't book accommodation, but we were right at the front for one of the rehearsals last year. It was brilliant. And then I checked on accommodation in Liverpool just 24 hours before and got a hotel room, a brilliant hotel room for a fraction of the price they were charging a year earlier. Oh, God, that is high risk. But look, you know, I'm not an advisor on these things but you know you could do that
Starting point is 00:35:31 noted yeah i was just going to say also we should mention amazingly a handful of people in the uk saw the partial bit of the eclipse the weather was largely terrible but in orkney one of our fellows callum potter cycled around the island of Rusey where he lives and saw the sun setting over the Atlantic with a beautiful bite out of it and also someone managed to see it from Gerlach Youth Hostel in the island out on the Isle of Harry it's amazing there's really nice photos we put them on our website so do take a look so you know I feel I felt a bit bad about recommending it given the number of people that simply didn't see anything at all. But it turns out at least maybe 10 people across the UK managed it.
Starting point is 00:36:10 Better than zero. Yeah, absolutely. That's an order of magnitude better. Exactly. So back to Voyager and on to some questions. And Becky, Chef Mike Barkley asks, will Voyager ever reach another star system? And if so, when?
Starting point is 00:36:28 Well, eventually, Mike, but it's a long time to wait, unfortunately. So let's do a bit quick, like back of the envelope calculation. So Voyager 1 is traveling at about 38,000 miles an hour. Voyager 2 about 34,000 miles an hour. So let's use Voyager 1 because it's just marginally faster.
Starting point is 00:36:45 38,000 miles an hour is 17 kilometers a second. So it sounds fast, right? But to travel just one light year, which is how far that light travels, you know, at 300,000 kilometers a second, like, you know, how far it goes in a year. Time is distance over speed. So it would take Voyager 1 about 17,500 years to go one light year.
Starting point is 00:37:07 Wow. Okay. So for context, the nearest stars are four light years away. You know, Proxima Centauri is about four light years away. So that speed, it's going to take you about 70,000 years or so. If it was going in that direction, which it's not, it's heading towards the constellation of euchus as well so um will it ever probably in our lifetimes yeah okay fair enough don't uh don't wait up for
Starting point is 00:37:35 that one um and then following that gem w asks can we work out which ones they could eventually fly past so i assume that's star systems yeah yeah it's a bit more complicated than you might like initially think because the stars aren't in fixed positions relative to each other so our current closest star is proxima centauri but that's not always going to be the case um the sun is moving, the other stars are moving, right? And so what actually happens if you sort of run a model forward based on the sort of directions and speeds that stars are going at the minute, is that a star called Jalise 445, which is currently 17 light years away from Earth, but in 45,000 years or so, it will become our closest star for around
Starting point is 00:38:23 about a few thousand years at about three and a half light years away so just ever so slightly closer than proxima centauri and when that happens voyager one will pass 1.6 light years away from jalees 445 and so technically then the sun will no longer be voyager's closest star it will be jise 445 I've really enjoyed that that's great which is pretty cool right yeah it's cool to think about I mean it's just a little red dwarf star and like you're not even gonna be able to see it with the naked eye I don't think when it even gets that close but still it's kind of cool to think that at some point you know it'll be like which if I need it if I desperately need a star which way is closer? Not the way I came. That way. Amazing. Okay, great question from Gem.
Starting point is 00:39:06 And Robert Benji182 asks, could you see NASA going back to Uranus or Neptune anytime soon? Yeah, Benji, that's a very good question. I think the answer is maybe. We hope so. Exactly, yeah. American planetary scientists all over the world would like to see that happen.
Starting point is 00:39:24 And they placed it as a high priority in what's called their Decadal Review, their sort of astronomy priorities for the decades ahead. And it's 714 pages long, this document, I should say. So don't dive through it all. But nothing has been confirmed. So there are sort of studies around it, but it's a long way to go. One of the probes that was proposed would be something that orbits Urananus and its moons and the other would be one that orbits neptune and particularly looking at triton as well because that's quite an exciting target a moon with sort of ice geezers on it and
Starting point is 00:39:54 so on and uranus is a bit more likely but if it happens it probably wouldn't be even launched until the second half of the 2030s and it wouldn't get there until around 2050 so I was just running the clock forward thinking yeah I'll definitely be retired but you know I'd be more than it'd be an amazing thing to see I think and everybody would really really love to get another look at the the ice giants okay Becky old black crow asks what is the theoretical distance limit of our current receiving stations? Are there any plans to upgrade them? Yeah, so currently NASA, ESA, JAXA, ISRO, all of these space agencies use the Deep Space Network, the DSN, to communicate not just with Voyager 1, but with robots on Mars and telescopes like JWST and Gaia L2. It's like this big network of radio telescopes worldwide. And it gives us
Starting point is 00:40:46 coverage like 24 hours a day with these antennae that are at least like 70 meters. That's about 230 feet across. Now, a spacecraft gives out a radio signal, like a certain energy or strength, right? And that then spreads out as it travels through space. So it ends up being much weaker by the time that it reaches Earth. So there's not just sort of the noise sensitivity of the antenna to take into account, but also like the strength of the signal
Starting point is 00:41:20 giving out by the spacecraft. Because as long as it's giving out a strong enough signal, no matter how far distant it goes, we should still be able to detect it here on Earth, right? So it's a little bit of a weird one because even just like, yes, we can upgrade the system by just adding more antenna. If you put more radio antenna over a larger area,
Starting point is 00:41:39 that sort of increases the size of your effective sort of radio telescope that you're picking things up with as well. And that means that you can detect weaker signals above like whatever noise background you have. Now I admit, I did try to find some numbers to put numbers on this for you, but it was very, very difficult to find. I can't find anywhere that like NASA records, this is like the strength of the signal or whatever that's given out and this is sort of like the noise floor on the deep space network but what i could find was that the voyager one signal that it gives out is one tenth of a billionth of a trillionth of a watt by the time that it reaches earth it's like 10 to the minus 22 or minus 23 or something like a zero with like 22 zeros after it and then a one.
Starting point is 00:42:26 So as it gets further away, that signal is going to get weaker, but I don't think it's near that noise floor of the deep space network just yet. I think what's more likely to happen is that it will run out of fuel first before we actually are not able to detect the signal from it anymore. Nice, okay.
Starting point is 00:42:43 And Robert, Lucy San wants to know, what's your favourite Voyager image? In brackets, I need a new desktop background. And is it the Saturn hexagon? Yeah. We know what Becky's favourite Voyager image is, don't we? Without a doubt. For me, it's not even necessarily the planets in close up.
Starting point is 00:43:01 There are a couple of things that come to mind, but one is that family portrait, which is the only image ever taken of almost all the planets mercury is just too close to the sun that was made by voyager 2 you know by carl sagan's initiative uh and it just shows how small all these worlds are compared with the sun and the blackness of space and so for me it's a really amazing thing to see you know they don't they don't look like dots or at best a few pixels with the bigger planets but it really deserves to be better known it's not just the earth in that but the whole solar system and i think one of the most beautiful images for me is actually of neptune and triton
Starting point is 00:43:34 and you see them in a way that you can't see them from the earth as crescents because you know we just don't get behind them on earth and it's also that kind of swan song from voyager 2 after its final encounter with the world. And it just makes me think about that tiny spacecraft beginning its journey into interstellar space after working so brilliantly for 12 years. And, you know, it's done another 35 years since that time already. And it also, I think, probably appeals to me because of things like the blueness of Neptune is somehow reminiscent. The crescents remind us a bit of our moon. And so, although it's obviously really alien,
Starting point is 00:44:06 it's somehow very familiar as well. So that's definitely a tip from me. Oh, great shout. And if you want to send in any questions to us for a future episode, then please do. You can email podcast at ras.ac.uk or find us on Instagram. It's at supermassivepod.
Starting point is 00:44:23 So shall we finish with some usual stargazing? Robert, what can we see in the night sky this month? Well, we're definitely, although it doesn't necessarily always feel like it, we're definitely enjoying spring skies now. And so the Milky Way is, I know, it's slightly hard to believe given the weather. Spring skies in winter weather.
Starting point is 00:44:39 Exactly, yeah, wrap up well. And the Milky Way is a lot less obvious, but the plus side of that is some of the more familiar constellations like Ursa Major and within that the plough, or the Big Dipper if you prefer in the USA, high overhead. And do look out for that.
Starting point is 00:44:53 If you look in the middle of the plough's handle or the bear's tail if you prefer, there's a classic double star, Mizar and Alcor, that you can see split with your eye. And if you have a small telescope, you can see that resolves into not just two but four stars because mysara is a binary and there's another distant unrelated one between that and alcor and that itself turns out to be a binary as well one time i think we should talk about binary stars there's simply so many of them but it's only visible with large telescopes now
Starting point is 00:45:17 but you know small telescope will show you quite a lot and other things to look for we've got boetes and the bright star arcturus is still really dominant in the sky. Leo the lion is there. Virgo and Spica is really obvious as well. And if you've got a small telescope, you can pick out those distant galaxies. It's a good time of year to do that if the moon's not in the sky. And nearby those is a constellation which I quite like just for its beauty, really. Corona Borealis, the northern crown, is one of those groups of stars that actually looks a bit like the object it's named for and that's that's quite unusual in constellation shapes and as we get closer to the june solstice we obviously get you know there's there's a shorter and shorter period of darkness in the sky in the night the nights get shorter um so the first part
Starting point is 00:45:59 of may is good for looking at some of these fainter things i was thinking of before and and another target might be messier 13 in hercules which is a big globular cluster. It's got several hundred thousand stars in it. It's not that hard to find if you get one of these apps or a decent chart. And if you get a pair of binoculars, you'll see a bright fuzz. And a moderate-sized telescope, you know, if you don't have access to one of those, go to, say astronomy society it just looks like this packed ball of stars it's absolutely beautiful now i should also mention that as last month we haven't got very many planets in the sky at the moment but if you're up early enough becky you can see saturn before dawn just in case if you're up at three o'clock in the morning um there's some nice photo ops on the 4th of may in the 31st of may it's near the moon and
Starting point is 00:46:43 in the second case mars is there as well but really to look at them in detail you need to wait till later in the year when they're a bit higher in the sky and it's a bit easier and the final thing I'll mention is that there is a meteor shower in May as well the Ito Aquarids shower which is on its best from the 5th to the 6th of May and that's best viewed from the southern hemisphere but even in the north you might get anything between 10 and 30 meteors an hour. So probably divide that by two in terms of what you can actually see with your eye. And it's actually related to debris from Halley's Comet. So a quite, you know, a quite nice evocative connection.
Starting point is 00:47:14 And this year, if you're around at that time of night on the 6th of May before dawn, there's no moonlight to interfere with the view. So if it's warm enough and if you feel inclined to go out and there's a clear sky, then, you know, do go out for half an hour and take a look. Amazing. it's warm enough and if you feel inclined to go out and there's a clear sky, then, you know, do go out for half an hour and take a look. Amazing. All right.
Starting point is 00:47:29 Well, thank you. I think that's it for this month and we'll be back next time with another bonus episode. And then after that, we're investigating the lunar standstill. More on that.
Starting point is 00:47:39 Very mysterious. As usual, contact us if you try some astronomy at home. It's at supermassivepod on Instagram, or you can email your questions to podcast at ras.ac.uk and we'll try and cover them in a future episode or one of our bonus episodes. Until then though, everybody, happy stargazing.

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