The Secret History of a Space Mission

Summary

Awesome Astronomy: "The Secret History of a Space Mission"

Podcast: Awesome Astronomy
Hosts: Paul, Dr. Jeni
Guest: Professor Stephen Eales (Cardiff University)
Date: June 19, 2026
Episode Theme: A deep dive into the untold challenges, triumphs, and discoveries behind the Herschel Space Observatory—a revolutionary mission that unlocked new cosmic secrets by observing the universe in the submillimeter waveband.

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Episode Overview

In this content-rich episode, Professor Stephen Eales shares his personal journey as a core member of the Herschel Space Observatory mission, revealing the "secret history" behind one of the most significant astronomical missions in recent decades. The discussion blends technical insight, human drama, and the pleasures and perils of international collaboration, ultimately highlighting how Herschel’s pioneering observations in the submillimeter waveband transformed our understanding of stars, galaxies, and cosmic origins.

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Key Discussion Points & Insights

1. Personal & Professional Background

• [01:07] Professor Eales describes his initial draw to astronomy—less from amateur stargazing, more from inspiration via the Apollo missions and science fiction ("My wife doesn't think I'm an astronomer because every time she sees something in the sky and says, what is it? I say, well, I don't know." – Eales, 01:38)
• Early career: Focused on using ground-based telescopes, which, despite the romance, were relatively "straightforward" compared to space missions.
• Entry into space astronomy was serendipitous, ultimately leading to involvement with Herschel.

2. Building and Launching a Space Astronomy Mission

• [03:07-06:53] The emotional and logistical intensity of preparing a space instrument: Many team members dedicate a decade or more, facing immense pressure, setbacks, and critical deadlines ("If you hit the critical path, you have to come in weekends, you have to apologize to your family, have to work. So it's been very stressful." – Eales, 04:58)
• The ever-present risk: Rockets sometimes fail. Eales recounts the Ariane 5's infamous first launch, a failure caused by legacy code ("the only people that were pleased about this were the Belgian team because it meant their software worked." – Eales, 06:53).
• The launch of Herschel itself: A successful but nerve-racking event.

3. Why the Submillimeter Waveband Matters

• [11:09-15:56] Herschel was designed to observe in a largely unexplored regime—submillimeter waves—where cosmic dust becomes transparent and new phenomena become visible.
• Every time astronomy has opened a new part of the electromagnetic spectrum, breakthrough discoveries have happened (e.g., quasars, pulsars, cosmic microwave background).
• Herschel’s potential revolutions:
  • Understanding star formation (overcoming the obscuring effects of cosmic dust).
  • Probing galaxy formation (unveiling early, dust-embedded cosmic structures unreachable by optical telescopes).

Notable Quote

"The big problem with understanding how stars are formed is this stuff here...cosmic dust. You can have the best possible optical telescope...you still would not be able to observe a star being formed simply because of the cosmic dust."
— Prof. Stephen Eales, [13:03]

4. The Human Side of Big Science

• [18:50-23:43]
  • Space missions resemble Hollywood productions: Long timelines, shifting teams, huge credit lists, and sometimes the originator of the idea is long gone by launch (“A space mission is a little like a Hollywood movie...people don't even remember who had the original idea.” – Eales, 19:10).
  • Fun amidst pressure: The Herschel teams fostered international camaraderie and creativity, setting up social events like sponsoring a dog race at Oxford Greyhound Stadium (Matt Griffin's leadership style).
  • Crisis moments: Five weeks before launch, a major flaw was found with Herschel’s pointing system. Rather than an expensive recall, they decided to let Planck, another spacecraft launched simultaneously, control Herschel's pointing—an incredibly high-stakes, last-minute workaround.

Notable Quote

"I just sent a message back to Matt, copied to all 200 people in the team, and I just let go...I just had a total rant about the ESA bureaucrats."
— Prof. Stephen Eales, [27:18]

5. From Launch to 'First Light'—Nerve-racking Steps

• [28:03-34:46]
  • Even post-launch, success is not guaranteed. Instruments may fail to survive vibrations; their function is only certain after "first light"—the first image or data capture.
  • The team's stress: "All your working life is hanging in the balance here." – Eales, [32:11].
  • Relief and discovery: After initial setbacks interpreting "first light" images, the team successfully captured submillimeter images of Messier 74 and Messier 66—proving the instrument’s functionality and opening a floodgate of discoveries.

6. Key Discoveries from Herschel

[34:59-48:46]

a) Structure of the Interstellar Medium

• Herschel’s images revealed that interstellar gas and dust form intricate filamentary structures, not just amorphous clouds. Stars were observed to form exclusively within these filaments.

b) The Origin of Cosmic Dust

• Directly detected a solar mass of dust created in Supernova 1987A, overturning prior skepticism about supernovae as dust sources. "The reason it had not been seen before was that the dust is very, very cold...it only radiates in the submillimeter wave band." – Eales, [39:01]

c) Galactic Case Study: Andromeda (M31)

• Advocacy, negotiation, and even a team vote (complete with national alliances) were required to secure time to observe Andromeda.
• The resulting Herschel image showcased a massive ring of star-forming activity—hidden at optical wavelengths by dust.

d) Probing Galaxy Formation with Gravitational Lensing

• Discovered cosmologically distant, dust-shrouded galaxies highlighted by gravitational lensing—a natural “cosmic magnifying glass.”
• Found these young galaxies are physically smaller but as massive as the Milky Way, and have extraordinary star formation rates.

Notable Quote

"We're really looking back in time...the light from me is taking a nanosecond to get to you. In this case, we're looking 12 billion years back in time."
— Prof. Stephen Eales, [46:44]

7. The Cosmic Origin of Water

• [49:50-52:44]
  • Tracing water from molecular clouds to stars, disks, and planets.
  • Crucially, Herschel data suggests the water molecules in Earth's oceans began on dust grains in ancient molecular clouds and likely survived through planet formation.

8. End of the Mission and What Comes Next

• [53:01-56:32]
  • Herschel’s instruments, among the coldest things in the universe, were cooled by a finite supply of liquid helium; when it ran out, the mission ended.
  • ESA faced choices: Let Herschel drift (not stable), crash into Earth (dangerous, bad PR), smash into the Moon (expensive but scientifically tempting), or a safe solar orbit (chosen).
  • Official “turn off” was performed by Martin Kessler, photo-commemorated with “Bond villain” glee.

9. The Ongoing Legacy

• [57:32-58:23]
  • Despite the mission’s end, Herschel fostered an extraordinary spirit of international cooperation—"the opposite side of humanity from the Donald Trump side"—where scientists from many nations contributed and worked together productively.
  • Herschel data remains valuable; much is available in public archives and will fuel research for decades.

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Notable Quotes & Moments

• On the stakes of space missions: "You've just spent 10 years of your life building an instrument which is strapped to the top of this Ariane 5 rocket...these things blow up occasionally." – Eales, [05:22]
• On discovering galaxies shrouded by dust: "There’s galaxies that are so shrouded in dust that you cannot see them even on what was then the deepest optical picture that had ever been taken of the universe." – Eales, [18:19]
• On scientific collaboration: “At least eight different countries involved. And everyone got on and everyone actually, I mean, there were moments when they didn’t, but everyone managed to actually communicate.” – Eales, [57:48]
• On cosmic time travel: "We are actually looking 12 billion years ago. Kind of mind blowing." – Eales, [49:11]

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Important Timestamps

• [07:02] – Audience is invited to imagine their instrument on the launch pad.
• [11:16] – Why Herschel was expected to revolutionize astronomy.
• [18:50] – The Hollywood movie analogy for space missions.
• [25:05] – The crisis with the pointing system and ESA’s high-risk solution.
• [32:01] – "First light": instrument comes to life.
• [36:04] – Filamentary structure of the interstellar medium.
• [39:01] – Dust in supernovae, direct detection.
• [43:05] – The Andromeda (M31) submillimeter image—new structures revealed.
• [46:44] – Gravitational lensing and looking back 12 billion years.
• [52:21] – The journey of water from clouds to Earth.
• [56:20] – Herschel’s shutdown and its commemoration.
• [57:48] – Reflection on international scientific cooperation.

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Audience Q&A Highlights

• On failsafes and duplicate instruments: Yes, there are always backup electronics both on the spacecraft and on the ground for troubleshooting. Example: The HIFI instrument was revived after an initial failure with on-the-ground diagnostics ([59:41]).
• On Herschel's data legacy: All data is archived, and vast portions remain to be mined and compared with other missions' data ([62:18]).
• On the practical and economic constraints around end-of-mission disposal ([64:02], [64:46]).
• On observing in the submillimeter from Earth: There are limited atmospheric windows, but for water spectral lines—a Herschel specialty—space-based observation is essential ([65:46]).
• On star formation in early/dust-free epochs (“population III” stars): Theories suggest first stars were much more massive; lack of dust and metals changed their formation ([68:13]).

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Conclusion

The Secret History of a Space Mission offers a frank, human, and inspiring look at what it truly takes to build, launch, and triumph with a groundbreaking astronomical space observatory. Blending the technical with the personal, Prof. Eales gives listeners a newfound appreciation for the collaboration, chaos, luck, and passion fueling the pursuit of cosmic discovery.

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"Being involved in a space mission is so absolutely fascinating...You look at the news at the moment and the world is on fire. But then you look at these things...everyone managed to actually communicate. It's a nice thing to think about."
— Prof. Stephen Eales, [57:38]

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For more resources, archived data, or to comment, visit awesomeastronomy.com or follow @awesomeastropod.

Transcript

[Host]

I'll start with Steve's Wikipedia description. Non Wikipedia, it says about Steve. Stephen Eales is a professor of astrophysics at Cardiff University, where he's currently head of the astronomy group. In 2015, he was awarded the Herschel Medal from the Royal Astronomical Society for outstanding contributions to observational astrophysics. He also writes articles and books about astronomy. But more than that, Steve was my PhD supervisor. He's a good friend. We've known each other for a very long time. He's a fantastic researcher, and he has brought along with him some copies of the book that contains the story that he is going to tell us today. So without further ado, I'd love to welcome Professor Stephen Eales, who's going to tell us the secret history of a space mission. So welcome Steve.

[Professor Stephen Eales]

Okay, could everyone hear me at the back?

[Interviewer/Moderator]

Oh, cool.

[Professor Stephen Eales]

Okay, so what I'm going to do today is try and give you an idea of what it's like to be part of a space astronomy mission. So it's going to be some astronomy, but. But it's also going to be a lot about actually what it's like to be part of these huge collaborations that do space astronomy. And perhaps I should give you a bit of background about myself.

[Interviewer/Moderator]

I didn't do amateur astronomy when I was younger. I can't recognize things in the sky.

[Professor Stephen Eales]

And I feel quite intimidated by some people here who show me these star maps and say, well, we just go from star to star and you find things. I. I don't know how to do that. My wife doesn't think I'm an astronomer because every time she sees something in the sky and says, what is it? I say, well, I don't know. In fact, the only reason I know now what's in the sky is because Jenny told me about this app that allowed you to actually look and see. I told my wife this, which was a mistake. So she now knows I just look

[Interviewer/Moderator]

at the app when.

[Professor Stephen Eales]

Anyway, so I didn't do astronomy when I was a kid. The reason I got involved in astronomy was really the Apollo mission and also science fiction. So some of you may be old enough to remember the sort of first Doctor who episodes. I watched Doctor who. I got really excited about going to other planets, all that kind of thing. So I gradually became an astronomer. But then for the first 20 years as an astronomer, what I did is I used use big telescopes around the world. And it's. I found it quite romantic. You go to Hawaii and you go up a mountain and use a telescope. But the truth is, it was actually quite easy because you go to a telescope and you have a telescope operator and you tell the telescope operator, well, I like to point at that position. And it's all quite straightforward. And the only things you need to worry about, really are the weather and also whether the instrument works. So it's not.

[Interviewer/Moderator]

It's quite an easy thing.

[Professor Stephen Eales]

But then sometime, at some point, just by luck, I got involved in the space.

[Interviewer/Moderator]

Space mission, the Herschel Space Observatory, which is shown here on the launch pad.

[Professor Stephen Eales]

And so I'm going to tell you about that. I'm going to tell you about some of the things that it discovered.

[Interviewer/Moderator]

But I think what I do first

[Professor Stephen Eales]

is I'm going to show you the launch of Herschel, and I want you to imagine what it's like. So let's do a bit of audience participation here. Can you put your hands up if you've ever built anything, any kind of device? Okay. Jesus Christ. So a lot of you have done that? I have. No, actually, I did do something. And when I was 13 years old, I tried to teach myself electronics, and I managed to build a little transistor radio set, one transistor radio set. And I tried to do more complicated things and it didn't work. And at that point, I gave up electronics and I've never built anything ever since. But if you are, if you put your hands up, what I want you to do is you are going to be the instrument team. I'm going to want you to imagine building an instrument for the Herschel Space Observatory is now on the top of that rocket, okay? The rest of you are like me. You're going to be an observer, you're going to be someone that's in the Herschel teams, and you have been involved in planning the mission.

[Interviewer/Moderator]

Now, so to get you in the

[Professor Stephen Eales]

complete mindset, if you built an instrument, what that means is you've just spent 10 years in part of a huge international team building an instrument. You've actually sat there, your working life, nine to five, you've been in the lab building an instrument. It's been quite high pressure. Every now and then, the instruments have slipped behind schedule.

[Interviewer/Moderator]

And if you're.

[Professor Stephen Eales]

If it's really serious, you hit a thing called the critical path, which means your bit of the instrument is holding up the instrument which is holding up the launch of the telescope. So you can imagine that's pretty stressful when that happens. When you hit the critical path, you have to come in weekends, you have to apologize to your family, have to work. So it's been Very stressful. Now, finally, your instrument is on top of this rocket, but you just spent

[Interviewer/Moderator]

10 years of your life building an

[Professor Stephen Eales]

instrument which is strapped to the top of this Ariane 5 rocket, which is a big chemical rocket like the things on bonfire nights. So it's quite scary because these things blow up occasionally. If you're an observer like me, you've still invested quite a bit of time, but it's probably been a couple of years, spent a couple of years going to committee meetings, trying to plan the

[Interviewer/Moderator]

program for the rocket, but it's still a couple of years of your life. So you've now a lot's invested in this rocket and it successfully working.

[Professor Stephen Eales]

And I guess the other thing you have to remember is rockets do blow up. This is an Ariane 5. The first Ariane 5 that was launched was going to launch a commercial satellite, but the commercial satellite fell through and it was decided or European Space Agency offered the launch slot to the cluster space mission, which is a space astronomy mission. And of course the cluster team say, oh, yeah, sure, I think 97 seconds after the launch of the first Ariane 5, it blew up and that went. Cluster went down the tube. A lot of people lost their jobs.

[Interviewer/Moderator]

The reason it blew up was because

[Professor Stephen Eales]

there was some code left from the previous Ariane 4 rockets. And the Ariane 4 rockets were not as powerful.

[Interviewer/Moderator]

And the Belgian team that had designed the software designed it so that if

[Professor Stephen Eales]

the acceleration hit a certain threshold, the software would realize that the rocket was off course and would self destruct.

[Interviewer/Moderator]

And that's what happened.

[Professor Stephen Eales]

And the only people that were pleased about this were the Belgian team because it meant their software worked.

[Interviewer/Moderator]

So anyway, what we're going to do

[Professor Stephen Eales]

is I'm going to show you the launch, so you have to imagine the situation. I was really scared when I watched

[Interviewer/Moderator]

the launch because I never had to

[Professor Stephen Eales]

worry about my rocket, my mission, blowing up.

[Interviewer/Moderator]

So it was really quite sort of scary. So just have to imagine.

[Professor Stephen Eales]

So what we're going to do is we're going to see the launch, hopefully. And so you might. I mean, you're probably not going to be too stressed by this because I wouldn't be talking about it if it actually blew up. And I can't. Is it off? It's.

[Launch Commentator 1]

I don't know if you heard Alex into the mic saying, my God, fabulous, wonderful shots into the blue, blue sky. Something we don't see every day. We hope you enjoy that. We'll have some replays at the end of the broadcast and you can see it again 770, 770 tons lifting off at H0.

[Launch Commentator 2]

Yes, we now hear the noise coming from the launch pad. Arriving here at the vicinity of the launch control center.

[Launch Commentator 1]

Takes over a minute to make 14 kilometers.

[Launch Commentator 2]

Yeah, to another 14 kilometers.

[Launch Commentator 1]

So what's happening now? We have the first powered flight phases, the boosters and the core engines.

[Launch Commentator 2]

The two solid boosters give a very strong initial boost. That will increase velocity from 0 to 7200 kilometers per hour, let's say 4500 miles per hour, approximately 20% of the targeted final velocity. The DDO just said that all parameters of the flight are nominal, so we're doing fine.

[Launch Commentator 1]

We're into the first powered flight phase. Ariane has three powered flight phases and one is unpowered. We'll describe each of them in turn so you can follow her along on her trajectory. Right, now, as we mentioned, the two solid boosters and the core main engine are burning.

[Launch Commentator 2]

Yes, they're for 2.3 minutes. So burn of the solid boosters.

[Launch Commentator 1]

Boosters should burn out in about 10 seconds. You'll probably be able to see that because the skies are clear. Unless she disappears into the clouds.

[Launch Commentator 2]

And after separation, we shall have lost 75% of the mass at liftoff.

[Launch Commentator 1]

Right on time. The boosters. The DDoS call out the boosters. Separation. This is what it looks like up there. There's two of them that fall away. The other one is out of the camera.

[Launch Commentator 2]

Gorgeous images from the separation.

[Professor Stephen Eales]

Okay, so it was successful. Launch was successful. But as I show later, there's a whole series of things that are going to happen later that are also nerve wracking because things can still go wrong. So the rocket has not blown up, but if you were the instrument, but if you're an instrument builder, your instrument is not blown up. But on the other hand, it hasn't worked yet. All the instruments were powered down during launch, but the launch is a lot of vibrations. And although the engineers tried to make sure that you could launch a camera and vibrate it and it would, it should still work. You're not going to be certain yet until you get some observations. So we'll get onto that later.

[Interviewer/Moderator]

As I said, it was rather nerve wracking.

[Professor Stephen Eales]

And one of the reasons why it

[Interviewer/Moderator]

was nerve wracking, in fact, I still find myself my blood pressure goes up

[Professor Stephen Eales]

when I watch this.

[Interviewer/Moderator]

One of the reasons it was nerve

[Professor Stephen Eales]

wracking is we knew that Herschel was, was going to do some revolutionary astronomy.

[Interviewer/Moderator]

And so let me kind of explain why that is.

[Professor Stephen Eales]

So here we've got the electromagnetic spectrum

[Interviewer/Moderator]

and the visible range of wavelengths is right in the middle. And all these different. You'll be familiar with many of these words, X rays, UV, gamma rays, etc. These are all wave bands in the

[Professor Stephen Eales]

electromagnetic spectrum, consisting of waves with wavelengths between certain values.

[Interviewer/Moderator]

And all these wave bands, bar one, had been used before for astronomy.

[Professor Stephen Eales]

And every time somebody had opened up a new wave band for astronomy, big discoveries have been made. So back in the day after the Second World War, when radio telescopes started to be used, astronomers discovered the existence of quasars, of rotating neutron stars, pulsars

[Interviewer/Moderator]

of radio galaxies, and also the cosmic

[Professor Stephen Eales]

microwave background was discovered as a result of that technology. So we knew that in the past, every time a wave band had been opened up for astronomy, exciting discoveries would be made.

[Interviewer/Moderator]

And the final

[Professor Stephen Eales]

wave band that hadn't been used for astronomy very much at all before was the sub millimeter wave band. And that is the wave band that Herschel was designed to observe in.

[Interviewer/Moderator]

So we actually, we were pretty sure,

[Professor Stephen Eales]

or we thought there was a chance that, you know, the first people that did big sub millimeter surveys of the sky would discover really exciting new things that had never been discovered before. So that was one of the reasons

[Interviewer/Moderator]

we were very excited.

[Professor Stephen Eales]

And the other reason we were kind of excited was we knew, or we thought we knew, that the sub millimeter wave band held the answers to some fundamental questions about the universe. And the first of those questions is, how does a star form? I think this is a Pleiades. Somebody mentioned the Pleiades a few moments ago. Very easy to. I should say. I'm saying it's very easy to observe stars. So I. I don't know how cloudy

[Interviewer/Moderator]

it's going to be tonight, but in principle, it's easy to observe stars.

[Professor Stephen Eales]

And so you might think that, well, it'd be fairly easy to investigate how stars are formed. Well, the big problem with understanding how

[Interviewer/Moderator]

stars are formed is this stuff here. So here's the Horsehead Nebula.

[Professor Stephen Eales]

It's a kind of black area in space.

[Interviewer/Moderator]

And the reason there's a dark area here is because of cosmic dust. And the Horsehead Nebula is actually a

[Professor Stephen Eales]

big cloud of gas and dust. And these clouds are where stars form. And the problem is that the dust gets in the way of optical radiation. So you can have the best possible optical telescope. You can have the Hubble Space Telescope.

[Interviewer/Moderator]

All the observing time on the Hubble Space Telescope, you still would not be

[Professor Stephen Eales]

able to observe star being formed simply because of the cosmic dust. Cosmic dust consists of tiny solid particles in interstellar space.

[Interviewer/Moderator]

So you think of dust as being

[Professor Stephen Eales]

a bit like smoke, little tiny fragments.

[Interviewer/Moderator]

The dust particles are made of what

[Professor Stephen Eales]

we call heavy elements, things like silicon and iron and oxygen. Very tiny, typically about 2 microns in size. And these fill galaxies. And it means that when you try and observe stars or as they form, you just can't see them because the

[Interviewer/Moderator]

stars form deep inside these clouds of gas and dust. So the reason why submillimeter wave band,

[Professor Stephen Eales]

we thought would be important for understanding

[Interviewer/Moderator]

how they're formed is he kind of

[Professor Stephen Eales]

gave us a way of looking through the dust, although it's a little bit complicated to explain.

[Interviewer/Moderator]

Here is a big cloud, and I've drawn a little cartoon in the middle of a newly formed star. We often call these protostars uniform star.

[Professor Stephen Eales]

Deep inside the cloud of gas and dust.

[Interviewer/Moderator]

And the visible and ultraviolet radiation from this star, you can't see it because it's absorbed.

[Professor Stephen Eales]

The radiation is absorbed by the dust grains around it.

[Interviewer/Moderator]

Now, the

[Professor Stephen Eales]

dust grains, they absorb the energy in the optical and ultraviolet light.

[Interviewer/Moderator]

And that means they're heated a little

[Professor Stephen Eales]

bit, and they're heated just about enough to emit submillimeter radiation.

[Interviewer/Moderator]

The dust grains around the star then emit submillimeter radiation. Then the submillimeter radiation travels through the

[Professor Stephen Eales]

rest of the dust and eventually is

[Interviewer/Moderator]

detected by a 7 millimeter telescope.

[Professor Stephen Eales]

So you're not exactly observing the protostar, but you're observing, you can see exactly where the protostars are.

[Interviewer/Moderator]

So you're kind of observing through all the surrounding levels of dust right close to the protostar. So we were kind of pretty sure

[Professor Stephen Eales]

that Herschel would tell us a lot about how stars are formed.

[Interviewer/Moderator]

And then the other big question that

[Professor Stephen Eales]

we wanted to address is another origin question, and that is how the galaxies formed. Now, you're all kind of interested in

[Interviewer/Moderator]

astronomy, so you probably know the immediate thing I'm going to tell you.

[Professor Stephen Eales]

This is a picture of the Hubble Deep Field. So this is a traditional optical picture of the sky, but taken with the Hubble Space Telescope is it was in the 1990s, it was one of the deepest, most sensitive optical pictures that had ever been taken of the universe.

[Interviewer/Moderator]

And if you look at this beautiful image, there's a star there, but everything

[Professor Stephen Eales]

else in this picture is a galaxy.

[Interviewer/Moderator]

And because the image is so sensitive,

[Professor Stephen Eales]

we're seeing the light from galaxies that are a long way away, which means that we're actually looking back in time.

[Interviewer/Moderator]

So the most distant galaxies in this

[Professor Stephen Eales]

image, the light has been traveling from them for about 10 to 12 billion years. So that means we're actually looking back in time 10 to 12 billion years.

[Interviewer/Moderator]

So in this picture, there are galaxies

[Professor Stephen Eales]

at every kind of time in the past, from about 12 billion years ago

[Interviewer/Moderator]

to the present day. And so you might think that trying

[Professor Stephen Eales]

to understand how galaxies formed, it's just a matter of taking an image like this, looking far enough out into space that you're looking far enough back in time that you can see the galaxies being formed. That is kind of true. You can look back in time to see the times of the first galaxies.

[Interviewer/Moderator]

But the thing that complicates matters is interstellar dust.

[Professor Stephen Eales]

Again, because the galaxies all contain dust.

[Interviewer/Moderator]

And here's the optical picture of the Hubble Deep Field.

[Professor Stephen Eales]

This is a sub millimeter picture that

[Interviewer/Moderator]

was taken in the late 1990s with

[Professor Stephen Eales]

a very primitive sub millimeter camera.

[Interviewer/Moderator]

And in the optical picture, there's about

[Professor Stephen Eales]

a thousand galaxies present.

[Interviewer/Moderator]

In this sub millimetre picture, there's probably about five. And there's hardly any detail at all. The white areas are basically the submillimeter

[Professor Stephen Eales]

sources, the sources of submillimeter emission.

[Interviewer/Moderator]

And the crucial thing is that if

[Professor Stephen Eales]

you go to the brightest sub millimetre source and you go to the same position on the optical picture, you don't find anything there at all.

[Interviewer/Moderator]

What this image is telling you is it's telling you there's galaxies that are

[Professor Stephen Eales]

so shrouded in dust that you cannot see them even on what was then the deepest optical picture that had ever been taken of the universe.

[Interviewer/Moderator]

So as a result of the work in the 1990s, we knew that many

[Professor Stephen Eales]

of the first galaxies are basically hidden by interstellar dust. So that was the second reason why we thought Herschel would be important, because it would allow us to see lots of these objects and really study the first moments in the birth of a galaxy. So before I get onto some of

[Interviewer/Moderator]

the astronomy that Herschel did, let me

[Professor Stephen Eales]

tell you a little bit more about what it's like being part of a big space mission. My kind of mentor in this. So, as I said, I didn't get

[Interviewer/Moderator]

involved in space astronomy till I was middle aged. And a lot of the stuff I knew I found out was completely new to me. And my mentor, who I'll introduce in a moment, told me, he said to.

[Professor Stephen Eales]

He said to me, steve, a space mission is a little like a Hollywood movie. And it is. One of the reasons it's like that is because often people don't even remember who had the original idea. And takes a long time for the thing to be developed. People get involved, people leave the team. There's a huge cast of people,

[Interviewer/Moderator]

and

[Professor Stephen Eales]

it's very, very complicated and very big budget. And if you've ever seen one of these Hollywood movies and stayed at the end for the credits, and you look at, especially one of these superhero movies, you find all these. You find about a thousand lines of people involved.

[Interviewer/Moderator]

So a space mission is like a Hollywood movie. Now, however, in this case, we actually

[Professor Stephen Eales]

do know who had the original idea,

[Interviewer/Moderator]

and we know why the original idea came about.

[Professor Stephen Eales]

Could anyone recognize this planet?

[Interviewer/Moderator]

Okay, obviously we recognize this planet because you're amateur astronomers.

[Professor Stephen Eales]

Although actually, as you'd have to look

[Interviewer/Moderator]

down to see it, you wouldn't necessarily. This. Anyway, this is. I'm being stupid.

[Professor Stephen Eales]

This is the Earth.

[Interviewer/Moderator]

And the reason it's interesting is it's a very interesting planet. One of the reasons interesting planet is

[Professor Stephen Eales]

it's the blue planet. And it's a blue planet because this planet contains a lot of water.

[Interviewer/Moderator]

Now, we know there's a lot of

[Professor Stephen Eales]

water on our planet. And a very fundamental question to ask is, how much water do you find elsewhere in the universe? How much water is there in the other planets and in the universe at large?

[Interviewer/Moderator]

And in principle, there's an easy way

[Professor Stephen Eales]

to answer this, because one of the

[Interviewer/Moderator]

things that we do routinely in astronomy

[Professor Stephen Eales]

is you can actually figure out what things are made off in space because

[Interviewer/Moderator]

you observe what are called spectral lines,

[Professor Stephen Eales]

which every element, every molecule emits radiation at certain very distinct wavelengths.

[Interviewer/Moderator]

So figuring out how much water there is, say, in a distance around a

[Professor Stephen Eales]

distant star, in a way, is quite simple. You just look for the spectral lines from water.

[Interviewer/Moderator]

The big problem is that because we

[Professor Stephen Eales]

live on a very watery planet, the water in our atmosphere absorbs those particular spectral lines, which means that from the surface of this planet, you. You can't observe water elsewhere in the universe.

[Interviewer/Moderator]

So back in the 1990s, a guy called Tice Grau proposed to the European

[Professor Stephen Eales]

Space Agency that sub millimeter telescope be launched into space to observe the water. Because a 7 millimeter wave band is

[Interviewer/Moderator]

where the water spectral lines appear.

[Professor Stephen Eales]

And from the date 1984, Herschel was launched in 2009. So it was 25 years from the

[Interviewer/Moderator]

time that Thais had this idea to

[Professor Stephen Eales]

the time that the mission was launched. And as I said, it's like a Hollywood movie.

[Interviewer/Moderator]

Big teams, long delays. And I don't think Tice was even

[Professor Stephen Eales]

involved in Herschel by the time it was launched. However, one thing that. So space astronomy in general has the

[Interviewer/Moderator]

big team's long delays. But one thing that I think was

[Professor Stephen Eales]

unique about Herschel was it was so much fun.

[Interviewer/Moderator]

So when I was writing my book

[Professor Stephen Eales]

about it, I interviewed lots of people

[Interviewer/Moderator]

involved in the mission. And one of the people who I interviewed was a guy called Michael Round Robinson, who's not the most fun loving character, but he said, I've been involved

[Professor Stephen Eales]

in seven space missions and Herschel was the most fun.

[Interviewer/Moderator]

And one of the reasons it was

[Professor Stephen Eales]

the most fun were the people involved.

[Interviewer/Moderator]

My mentor in all of this, somebody that Jenny will remember, is this guy

[Professor Stephen Eales]

here, a guy called Matt Griffin. And Matt was the leader of the team that built the, probably the most important instrument for Herschel.

[Interviewer/Moderator]

So it's called the SPIRE camera. And it was led by Matt and

[Professor Stephen Eales]

he had a team of 150 scientists

[Interviewer/Moderator]

in eight different countries. And Matt was another guy at Cardiff University. And Matt and a number of other people made the project fun. But one of the things Matt did

[Professor Stephen Eales]

was that he had this big team from different countries. And to make sure that people got on and interacted well, we had a team meeting every six months in one of these countries. And Matt always tried to arrange some big social event.

[Interviewer/Moderator]

And he was very inventive in this. So one of the social events was a trip to the Oxford Greyhound races.

[Professor Stephen Eales]

And Herschel actually sponsored a race of this.

[Interviewer/Moderator]

And this little chap here is the winner of the Herschel race at the Oxford Greyhound Stadium. So Matt made things fun

[Professor Stephen Eales]

and this

[Interviewer/Moderator]

was one of the things he also did, which is I didn't find so much fun at the time.

[Professor Stephen Eales]

So remember, launch was stressful. Five weeks before the launch, the teams that built the instruments and the teams that designed the observing program hadn't got anything to do because Herschel was out in French Guiana. Everyone was getting ready to launch it, but I had nothing to do.

[Interviewer/Moderator]

The instrument teams had nothing to do with. So you have to remember it was

[Professor Stephen Eales]

a very tense time.

[Interviewer/Moderator]

And the other thing you have to know to understand what happened next is

[Professor Stephen Eales]

that in the 1990s, the European Space Agency was very short of money.

[Interviewer/Moderator]

And at the time there were two spacecraft or two space astronomy missions that were in preparation.

[Professor Stephen Eales]

One was Herschel and one was Planck. And there was a big financial crisis and various people wanted to cancel the

[Interviewer/Moderator]

missions or merge the missions. And in the event, what happened was that the ESA decided to launch Herschel

[Professor Stephen Eales]

and Planck on the same rocket.

[Interviewer/Moderator]

And so here's the Ariane 5 at Kourou in French Guiana. Here is Planck, here is Herschel above it.

[Professor Stephen Eales]

Nobody was very happy about launching the two spacecraft together.

[Interviewer/Moderator]

One of my friends said it was a high risk Fudge, designed to make the things happen.

[Professor Stephen Eales]

And everyone said, well, it's putting all your eggs in one basket.

[Interviewer/Moderator]

So it was all a bit scary,

[Professor Stephen Eales]

but we thought it'd be okay.

[Interviewer/Moderator]

And then five weeks before launch, Matt sends the team a memo describing a meeting that has taken place that day

[Professor Stephen Eales]

at European Space Agency headquarters in Paris.

[Interviewer/Moderator]

And it was terrible. Since March 31, I remember vividly, I'm

[Professor Stephen Eales]

sitting there in my house reading my emails late at night on the 31st of March, get this message from Matt.

[Interviewer/Moderator]

He describes this meeting that's taken place

[Professor Stephen Eales]

and apparently there's a crisis in French Guiana because they've suddenly discovered the ESA technicians have discovered that the pointing system on Herschel is broken. Now, the pointing system on a telescope is the thing you use to point in different directions. We were going to use Herschel to observe all these different galaxies and gas clouds. So you obviously have to point the thing in the right direction. So it was a total crisis. And the meeting taking place in Paris had been designed to come up with a solution. And they looked at various options. And the first option to me was the obvious one, which was that, okay, things still on the ground, let's ship Herschel back to the Netherlands, to the Space Technology center in the Netherlands and fix the problem. And the meeting had looked at this option and they had decided that this would cost about 100 million euros, which sounds an awful lot, but it was only 10% of the total cost of

[Interviewer/Moderator]

Herschel, which was about a billion euros.

[Professor Stephen Eales]

But anyway, 100 million euros in the context of the ESA budget was too much. I could feel myself tense now as

[Interviewer/Moderator]

I'm describing what happened.

[Professor Stephen Eales]

They had decided there was a better option, and they looked back to the work that had been done in the 90s, looking at merging the two missions, and they had realized that they could bolt Herschel and Planck together and they could use the Planck pointing system to point Herschel in different directions in the sky.

[Interviewer/Moderator]

Okay? And so what they had decided is

[Professor Stephen Eales]

they would do that. And then for the three years of the Herschel mission, Planck would point Herschel around the sky, and then at the end of that time, they'd separate the two missions, and then Planck would do its own mission. And I just thought, this is terrible. I'd been anticipating it all the time because I just assumed that something would go wrong. And I read this email and I just sent a message back to Matt, copied to all 200 people in the team, and I just let go. I don't think I used any four letter words, but I was Pretty close to it. I was just saying, I just had a total rant about the ESA bureaucrats, but I thought, you know, fine.

[Interviewer/Moderator]

Went into work the following morning. I still haven't entirely forgiven that for that one. Anyway, five weeks later it was launched. And this is the last picture that

[Professor Stephen Eales]

human beings had of Herschel.

[Interviewer/Moderator]

This was a picture taken by a guy called Gustavo Muller, who was an Argentinian amateur astronomer. And he's got a picture here which has got Herschel there. Planck is now safely separated, thank God. And this thing is the cage that

[Professor Stephen Eales]

was used to keep the two missions

[Interviewer/Moderator]

on the Ariane 5.

[Professor Stephen Eales]

So they've successfully launched, they're on their

[Interviewer/Moderator]

way, but

[Professor Stephen Eales]

we still don't know whether the things are going to work or not. Obviously I'm here, so you know they're going to work. But think back to the time people who have built an instrument, you don't know whether your instrument is going to work yet. And Matt said to me once, he said, I wasn't worried at all about launch. He wasn't worried at all about launch, because what worries him was whether his instrument would work. If the Ariane 5 had blown up, he said, nobody will ever know whether we built the instrument successfully. It would be fine.

[Interviewer/Moderator]

So Matt's moment is about to come because eight days into the launch,

[Audience Member 1]

he's

[Professor Stephen Eales]

going to turn on his instrument and see if it's actually responding.

[Interviewer/Moderator]

But the first thing I should tell

[Professor Stephen Eales]

you is where Herschel's going. And this is going to, this is important because Herschel is going to go a long way from the Earth.

[Interviewer/Moderator]

So Herschel is going to a place called the second Lagrangian point L2, which

[Professor Stephen Eales]

is about a million miles from the Earth and it's on the opposite side of the Earth from the Sun. And the reason for that is if

[Interviewer/Moderator]

the AT L2, Herschel will orbit the

[Professor Stephen Eales]

sun in the same time that the Earth takes to orbit the sun, which means the, the sun, the Earth and Herschel will always be in a straight line. So it's important with the space telescope not to point it close to the Earth or the Sun. And if the sun and the Earth are always in the same direction, it makes it much easier.

[Interviewer/Moderator]

The other reason why L2 is important

[Professor Stephen Eales]

is because it's so far from the Earth, it means that any sub millimeter radiation from the Earth will be less important. And one of the problems with the submillimeter wave band is everything emits submillimeter radiation. You're emitting a huge amount of submillimeter radiation as you sit Here, sub millimeter instruments, cameras emit lots of sub millimeter radiation unless they're cooled to incredibly low temperatures. And the Earth is a huge beacon of sub millimeter radiation. So the further from the Earth you go, the better.

[Interviewer/Moderator]

Now, the problem with L2 is it's so far away.

[Professor Stephen Eales]

So if anything is going to go wrong with the instruments now, you can't send anyone up to fix it. So some of you will remember what happened to Hubble when it was launched in the early 1990s.

[Interviewer/Moderator]

Hubble.

[Professor Stephen Eales]

They launched, Hubble took a picture of a star. The star was out of focus, and they realized the mirror on Hubble had not got the right shape. There had been an error in the grinding program that grounds the mirror for Hubble. Now, fortunately, because Hubble is only flying about 300 miles above the Earth, it was possible to send astronauts up in the shuttle to put a basically a set of spectacles on Herschel, on Hubble to fix it. But we know this is not going to happen with Herschel. It's going too far away anyway.

[Interviewer/Moderator]

Eight days into the mission, Matt has to turn the thing on.

[Professor Stephen Eales]

And Herschel is now so far away that it takes light or radio waves 4 seconds to get to the instrument. So Matt is going to press the switch. He's going to send, send the signal to Herschel. It's going to hopefully wake his instrument up. If the instrument wakes up, a mirror's going to move and that's going to create a wiggle. And four seconds later, Matt's team is going to see something on the screen. They're going to see a wiggle on the screen. But you have to remember it's going to be a very long eight seconds. Okay, so I'm going to, before I show you what they saw, I'm going to put my hand up and then eight seconds later, I'm going to switch the slide. So you just have to think about this. So this is your whole life here. Well, not your whole life. Your working life is hanging in the balance here. If you, if you built the instruments, if you're an observer, it doesn't matter.

[Interviewer/Moderator]

Not so much anyway.

[Professor Stephen Eales]

So put the hand up. He saw the wiggle.

[Interviewer/Moderator]

So that's the wiggle that appeared on the screen. So that's the next step.

[Professor Stephen Eales]

So the instrument is now woken up. So it's kind of survived launch. You know, it survived launch to some

[Interviewer/Moderator]

extent, but you're not going to know

[Professor Stephen Eales]

whether it's actually really working until you take the first picture. First picture is what we call first light. And that occurs in all telescopes. Have a telescope on the ground, always have first light when you first use it to look at a star or something and see if you're actually detecting anything.

[Interviewer/Moderator]

So first light for match instruments. I'm going to show you the first light team. Here's the first light team. It's not a very exciting venue. It's just an office in the Rutherford Appleton Laboratories. This is Matt at the back. These are the, this is the first light team.

[Professor Stephen Eales]

And the reason they look happy is they've just had a really bad 15 minutes because when they first looked at the first light images, they couldn't see anything. And they didn't think that instrument had worked.

[Interviewer/Moderator]

But by fiddling around with the data

[Professor Stephen Eales]

reduction pipeline, they finally saw something.

[Interviewer/Moderator]

And this is actually what they finally saw. These are the first light images from Matt's camera.

[Professor Stephen Eales]

These are pictures of two nearby galaxies. But you can probably look at these tonight, I suspect because it's April overhead. These are Messier objects. You've got all these telescopes out here. If the clouds clear, I've challenged you to see Messier 74. Messier 66, is that right? Okay, so 66. So the challenge is see Messier 66.

[Interviewer/Moderator]

Anyway, these are the first light sub millimeter images of these two galaxies.

[Professor Stephen Eales]

These are the first two ever sub millimeter images of these galaxies.

[Interviewer/Moderator]

Now, as it happens, these sub millimeter

[Professor Stephen Eales]

images do not look that different than the optical images.

[Interviewer/Moderator]

So we've not really seen anything new here. But what was really important when they looked at these first images is if you look at the M74 images, you can see all these red dots.

[Professor Stephen Eales]

Each of these red dots is a distant galaxy.

[Interviewer/Moderator]

And this is sub millimeter radiation from very distant galaxies. So these are the galaxies that I'm

[Professor Stephen Eales]

talking about, the galaxies early in the history of the universe. Galaxies that are basically in a formation phase that are emitting submillimeter radiation.

[Interviewer/Moderator]

So when Matt saw these pictures, he

[Professor Stephen Eales]

knew that the telescope, his camera, was

[Interviewer/Moderator]

going to be successful. So let me now go through some of the discoveries that Herschel made.

[Professor Stephen Eales]

So some of the most spectacular pictures

[Interviewer/Moderator]

were the very early pictures when Herschel

[Professor Stephen Eales]

took images of the clouds of gas and dust in our own galaxy.

[Interviewer/Moderator]

And these are some Herschel images. And what we're seeing here is radiation from dust. And the colors in the images tell

[Professor Stephen Eales]

you the temperature of the dust.

[Interviewer/Moderator]

Now, none of the dust is very warm. Probably the warmest dust here is about

[Professor Stephen Eales]

minus 200 degrees centigrade.

[Interviewer/Moderator]

But the very cold dust is shown in red, the white and the Blue is warmer dust.

[Professor Stephen Eales]

So you can see where there are things that are warm dust.

[Interviewer/Moderator]

And the first big discovery that was

[Professor Stephen Eales]

made and it kind of jumped out of the screen, so it wasn't some

[Interviewer/Moderator]

kind of subtle discovery, was that interstellar

[Professor Stephen Eales]

gas and dust seems to be distributed in long filaments. So I talked earlier about stars forming in clouds of gas and dust. And we tend to talk about, or for years we've talked about interstellar gas as being in these big clouds. And the term cloud is just something we've taken from our kind of natural

[Interviewer/Moderator]

world because in the first observations, gas

[Professor Stephen Eales]

observations of the interstellar gas, they saw things that looked like clouds.

[Interviewer/Moderator]

But we now think that cloud is

[Professor Stephen Eales]

kind of not really quite right, that actually the structure of interstellar gas is filamentary. You see a web of filaments everywhere.

[Interviewer/Moderator]

And the second big discovery was that where you see the hot dust, places

[Professor Stephen Eales]

where the dust is warmer, places where there's protostars, newly formed stars.

[Interviewer/Moderator]

And what we found, or what the teams found, is that stars always appear

[Professor Stephen Eales]

to be born in these filaments. So the places that stars are born is in these filaments of gas and dust.

[Interviewer/Moderator]

So the origin of stars. I mean, I'm describing the discoveries very quickly, so there's obviously a lot, much more than that, But I'm just going to go through one after another. So the next one I want to

[Professor Stephen Eales]

go through is how the question of how, another origin question, how was the actual dust formed? And this may not be so exciting to you, but for people like me that have spent our careers looking at interstellar dust, the question of how the dust grains were formed in the first place is quite an interesting one.

[Interviewer/Moderator]

And one of the possibilities had always

[Professor Stephen Eales]

been that dust might be formed in supernovae because dust is made of things like silicon and oxygen, and silicon and oxygen are made in supernovae.

[Interviewer/Moderator]

And back in the 80s, astronomers had

[Professor Stephen Eales]

a huge opportunity because of the discovery of a supernova called Supernova 1987A. Now, one of the irritating historical facts about supernovaean astronomy is the telescope was first used In, I think, 1609, when Galileo used it to observe phase of

[Interviewer/Moderator]

Venus and moons of Jupiter.

[Professor Stephen Eales]

The last visible supernova in our own galaxy was five years before that.

[Interviewer/Moderator]

And in the four centuries since, no

[Professor Stephen Eales]

supernova had been discovered in the galaxy, which meant that we found supernovae in other galaxies, but they were very faint. It was very hard to investigate what was going on.

[Interviewer/Moderator]

But Supernova 1987A wasn't in our own

[Professor Stephen Eales]

galaxy but it was in the Large Magellanic Cloud, which is the closest dwarf galaxy to our own.

[Interviewer/Moderator]

So it gave astronomers a huge opportunity

[Professor Stephen Eales]

to really study how supernovae, what happens to a supernova.

[Interviewer/Moderator]

And in particular, people like me in

[Professor Stephen Eales]

the 25 years since Supernova 1987A, we look for the dust. We look for any sign that dust

[Interviewer/Moderator]

was being formed in the supernova and

[Professor Stephen Eales]

we hadn't really seen anything.

[Interviewer/Moderator]

So when Herschel was launched, people generally

[Professor Stephen Eales]

assumed that dust could not be made in supernovae.

[Interviewer/Moderator]

But then sometime after launch, Herschel observed the Large Magellanic Cloud. And you can't see very well here because it's a bit too light.

[Professor Stephen Eales]

But right at the position of supernova 1987A, there was a faint blob.

[Interviewer/Moderator]

And when people figured out how much

[Professor Stephen Eales]

dust that meant, it meant that about a solar mass, a sun's worth of dust had been formed in supernova 1987A. And the reason it had not been seen before was that the dust is very, very cold.

[Interviewer/Moderator]

And it didn't radiate.

[Professor Stephen Eales]

It only radiates in the sub millimeter wave band. So the reason it was discovered was simply because of the launch of Herschel. Now, I said that M74 and M66

[Interviewer/Moderator]

don't look that different in the sub

[Professor Stephen Eales]

millimeter wave band than they do in

[Interviewer/Moderator]

the optical wave band. Here is a galaxy

[Professor Stephen Eales]

where there is a difference. Okay, here's the audience participation. Who could recognize this galaxy. Well, this is a lot higher fracture

[Interviewer/Moderator]

than I normally get.

[Professor Stephen Eales]

Okay, so this is M31. This is a picture taken by an amateur astronomer.

[Interviewer/Moderator]

It was taken with a. I happen to know this because I looked it up.

[Professor Stephen Eales]

It's taken with a 16 inch telescope in Massachusetts by a guy called Robert Gendler.

[Interviewer/Moderator]

I think it's the kind of standard

[Professor Stephen Eales]

picture that's always used of Andromeda.

[Interviewer/Moderator]

Although with the new technology that's available now, I know that amateurs can get

[Professor Stephen Eales]

much better pictures of M31 than this picture because I'd seen them.

[Interviewer/Moderator]

And anyway, M31, biggest nearby, sorry, biggest,

[Professor Stephen Eales]

closest big galaxy to our own. So very, very important.

[Interviewer/Moderator]

And we ended up. I mean, I was not involved in the previous work, but I was involved in this because it was my team that did this.

[Professor Stephen Eales]

So we decided we'd observe Andromeda with Herschel. It wasn't actually straightforward to do this because in the first round of Herschel observations, Andromeda had been missed.

[Interviewer/Moderator]

And it was only when I was

[Professor Stephen Eales]

slightly complicated story, which I wasn't intended to Give.

[Interviewer/Moderator]

But I went to the first Herschel meeting, which was in Madrid, and I was in a bar in Madrid talking to another astronomer, a Belgian astronomer called

[Professor Stephen Eales]

Martin Gars, Martin Barce. And we realized that Herschel had not been observed.

[Interviewer/Moderator]

And we kind of made a sort

[Professor Stephen Eales]

of pledge to each other. We go back to Cardiff and he

[Interviewer/Moderator]

would go back to Belgium, and we

[Professor Stephen Eales]

get eight hours of observing time from

[Interviewer/Moderator]

each team to observe M31 Andromeda. And Martin successfully did this.

[Professor Stephen Eales]

And I went back to Cardiff and sent a message round to the nearby

[Interviewer/Moderator]

Galaxy team, which is all over Europe,

[Professor Stephen Eales]

and said, look, no one's observed Andromeda. Can we just spend eight hours of

[Interviewer/Moderator]

our remaining time to do this?

[Professor Stephen Eales]

And the leader of the team was a very nice person, a friend of

[Interviewer/Moderator]

mine called Sue Madden in Paris and

[Professor Stephen Eales]

she said, oh, no, we can't do this because I want to use all the remaining observing time to observe dwarf galaxies, which are actually interesting galaxies.

[Interviewer/Moderator]

But I thought, this is absolutely crazy.

[Professor Stephen Eales]

Anyway, sue did agree that we'd have a vote on it. So you don't really think of astronomers having votes on what to observe, but we had a real vote on doing this.

[Audience Member 2]

And

[Interviewer/Moderator]

I came in, the morning of the vote was about to be counted, all the votes had come in, and a friend of mine, a guy called Walter Gere, he came to me, he

[Professor Stephen Eales]

said, steve, you've got to do something. You're two votes behind. The French have voted as a bloc against observing Andromeda and in favor of

[Interviewer/Moderator]

voting favor of observing dwarf galaxies.

[Professor Stephen Eales]

So I kind of felt like some kind of old fashioned sort of politician. I was sort of sending emails around everyone I could think of who hadn't voted, say, please think about this.

[Interviewer/Moderator]

Observe Andromeda. So we did observe Andromeda, but it was partly as a result of kind

[Professor Stephen Eales]

of slightly shenanigans in the.

[Interviewer/Moderator]

In the vote. So we observed Andromeda. And this is what we saw, which is very different than what you see, the visible wavelength.

[Professor Stephen Eales]

This picture appeared on Stargazing live on the BBC in early 2010. And we observed it early because the BBC team wanted us to. So the BBC team actually very helpful. They contacted the European Space Agency and said, could you bring Herschel ahead in the schedule?

[Interviewer/Moderator]

So we did this. And what you can see is something very different. So in the optical picture, there's a big red bulge in the center of old stars, faint blueness in the disk.

[Professor Stephen Eales]

And the blueness is because there's a

[Interviewer/Moderator]

lot of stars being born in the

[Professor Stephen Eales]

disk and new stars tend to be

[Interviewer/Moderator]

blue stars what you see in this sub millimeter picture, you're observing dust radiation from dust, and there's not that much

[Professor Stephen Eales]

radiation in the center because in the

[Interviewer/Moderator]

center of Andromeda there's lots of old

[Professor Stephen Eales]

stars, but very little gas and dust.

[Interviewer/Moderator]

But what you do see in Andromeda that you don't really see in the optical picture is this huge ring.

[Professor Stephen Eales]

And the ring is there because there's large numbers of stars being formed in

[Interviewer/Moderator]

a ring around the center of Andromeda.

[Professor Stephen Eales]

You don't see these in the visible picture because of all the dust, but the dust absorbs the optical light from the stars. The dust is heated a bit and then emits submillimeter radiation.

[Interviewer/Moderator]

And so you see this beautiful ring. So in this case, the submillimeter is

[Professor Stephen Eales]

giving you a different perspective on the universe to the optical picture. Now, I said that one of the

[Interviewer/Moderator]

big questions we addressed is the origins question of how galaxies are formed. We found lots of very distant galaxies, and this shows one of these galaxies. Now, this is actually not a Herschel picture.

[Professor Stephen Eales]

This is a more detailed sub millimeter picture we took a few years later

[Interviewer/Moderator]

with a telescope called the Atacama Large Millimeter Array.

[Professor Stephen Eales]

But it's of a submillimeter galaxy, a

[Interviewer/Moderator]

submillimeter emitting galaxy that we discovered with Herschel. And what you see is something very strange. You, you see this is a sub millimeter picture and you see this kind of ring or partial ring. And what you're seeing here is there's

[Professor Stephen Eales]

a thing called a gravitational lens. In this picture.

[Interviewer/Moderator]

There's a galaxy right in the middle

[Professor Stephen Eales]

of the ring that you can't see. And the reason you can't see it is that it contains very little dust.

[Interviewer/Moderator]

So it's emitting very little sub millimeter irradiation.

[Professor Stephen Eales]

So it's invisible in our submillometer picture.

[Interviewer/Moderator]

But the gravitational field of that galaxy is bending light or sub millimeter radiation

[Professor Stephen Eales]

from a more distant galaxy around it.

[Interviewer/Moderator]

So if you think about it, if

[Professor Stephen Eales]

you imagine I'm a gravitational lens, there's a galaxy behind me, the radiation from that galaxy has been bent around me by gravitational force.

[Interviewer/Moderator]

So you get this very strange thing. And the gravitational lens, the invisible galaxy,

[Professor Stephen Eales]

is kind of like a big cosmic magnifying glass.

[Interviewer/Moderator]

It's a slightly strange cosmic magnifying glass

[Professor Stephen Eales]

because it's not only magnifying the radiation, it's also distorting it. And obviously that's not a good thing

[Interviewer/Moderator]

in a magnifying glass. But it's possible to correct for the distortion and take this correct for the distortion and then what you get is something like this. This is the sub millimeter image of that distant galaxy. But it's now being corrected for the distortion. So even though this is obviously visible

[Professor Stephen Eales]

colors, it's a representation of the sub millimeter radiation.

[Interviewer/Moderator]

So it's a sub millimeter picture. And you see, it doesn't. The galaxy doesn't look much like galaxies nowadays. Got these big blobs everywhere. And in this case this particular galaxy,

[Professor Stephen Eales]

we are actually looking set 12 billion years ago.

[Interviewer/Moderator]

So we're looking back in time. And it's important to realize we are

[Professor Stephen Eales]

really looking back in time here. Because often when astronomers say you look back in time, it's tempting to think, well, what they're doing is they're inferring what was there back in time. But we're really looking back in time in the same way that when you're looking at me, you're actually looking back in time a small amount, because the light from me is taking a nanosecond to get to you. So you're actually looking at me a nanosecond back in time. In this case, we're looking 12 billion years back in time just because the radiation has been traveling 12 billion years.

[Interviewer/Moderator]

So we really are looking at a galaxy 12 billion years ago. And the first thing that's kind of interesting, this is a galaxy that's being born.

[Professor Stephen Eales]

First thing that's interesting is it's a very small galaxy. In terms of physical dimensions, it's not particularly large. So in our own galaxy, the kind of sun is in the galactic suburbs and is about 30,000 light years from the center of the galaxy. So here's the sun, here's the center of the galaxy, about 30,000 light years between them. This whole distance here is about 6,000 light years. So when we look at these very young galaxies, they're physically very small.

[Interviewer/Moderator]

But the other thing that's interesting is

[Professor Stephen Eales]

that although they're physically small, most of the mass is still there.

[Interviewer/Moderator]

So the mass of this galaxy is, is around about the same mass as

[Professor Stephen Eales]

our galaxy, but it's packed into a region much, much smaller.

[Interviewer/Moderator]

Now, one thing we could do, I said, it's a kind of a galaxy.

[Professor Stephen Eales]

It's in the process of formation.

[Interviewer/Moderator]

Haven't really explained why we know this. The reason we kind of know this is we can estimate how rapidly stars

[Professor Stephen Eales]

are forming in this galaxy.

[Interviewer/Moderator]

And the stars are forming in this

[Professor Stephen Eales]

galaxy about 160 times greater than the rate at which they're forming in, in our own galaxy. And this means that's fast enough to build a whole massive galaxy in about 1% of the age of the universe. Still a long time, but it's only a tiny fraction of the total life of the universe. So we're pretty sure these galaxies are galaxies in the process of formation.

[Interviewer/Moderator]

And then finally, a couple of things we found. We found that this galaxy is spinning

[Professor Stephen Eales]

like our galaxy is, but it's spinning five times faster. And we also discover that its disk is collapsing.

[Interviewer/Moderator]

So we, we found out some quite fundamental things that this galaxy, although we

[Professor Stephen Eales]

still don't know this, is one galaxy, we still don't know whether this is typical of other galaxies.

[Audience Member 2]

What do you mean when you say the disk is collapsing?

[Professor Stephen Eales]

Well, I kind of, I didn't explain very clearly that at all. We've got a rotating disk and what we were able to do was to measure, kind of look through the disk to look at the, the spread of velocities. And it's possible to show that the spread of velocities is, suggests that the disk is actually collapsing that way. 12 billion light years, 12 billion years back in time. Kind of mind blowing. Let me finish off with a question that is much sort of more kind of basic.

[Interviewer/Moderator]

Bring it back to a human level.

[Professor Stephen Eales]

Hopefully it won't rain tonight. But that water, the big question is where does the water come from? So the water comes from the clouds,

[Interviewer/Moderator]

obviously the water in your bathtub, obvious

[Professor Stephen Eales]

answer would be the water comes from nearby reservoir. But then where does the water come from before that?

[Interviewer/Moderator]

Now, one thing I never realized myself

[Professor Stephen Eales]

fully is the water molecule is incredibly stable. So actually the water on the Earth now, same water molecules on the Earth now were there four and a half billion years ago. So the water on the Earth has been here a long time. But then you say, well, okay, where did the water come from before that?

[Interviewer/Moderator]

And we had a partial answer to

[Professor Stephen Eales]

that before Herschel went up.

[Interviewer/Moderator]

And the. We knew some things. So we were pretty sure that a

[Professor Stephen Eales]

lot of the water in the universe forms on the surface of dust grains.

[Interviewer/Moderator]

Another reason why dust is important deep in these big clouds of gas and

[Professor Stephen Eales]

dust in which stars form.

[Interviewer/Moderator]

So I've shown that here. So here's a big cloud of gas and dust. These are some little dense regions.

[Professor Stephen Eales]

And these little dense regions are going to collapse to form stars.

[Interviewer/Moderator]

And we know a lot of water in the universe is in these big clouds as ice layers around dust grains. And we knew that these dense regions would eventually collapse to form stars. Here's an artist's visualization. Here's a star forming. And actually what Happens with one of these little dense bits is it collapses to form a disk. So you get, you collapse to form a star in the middle, but then there's a disk around it, and the

[Professor Stephen Eales]

disk around it will eventually form planets,

[Interviewer/Moderator]

and then the planets form out the disk. Now, the big question though was when the disk forms here, the disk gets very hot. So we weren't really sure whether the disk would be so hot that the water molecules that were formed here would

[Professor Stephen Eales]

then be split into hydrogen and oxygen in the disk.

[Interviewer/Moderator]

And then what that would mean is then the water that's in the planets would have reformed in the disk. So the water molecules on the Earth today would not be the same water

[Professor Stephen Eales]

molecules that were deep in these, in this molecular cloud. Summarizing a huge amount of observations, what we found, or the Herschel teams found, was that in the disk, the disk does not actually get hot enough to destroy the water.

[Interviewer/Moderator]

So what that means is that the water that does come out the taps

[Professor Stephen Eales]

today and the water that may fall

[Interviewer/Moderator]

from the sky tonight was once in

[Professor Stephen Eales]

the ice surrounding the dust grains, deep inside molecular clouds. So the water trail that leads to the Earth has started life deep inside a giant molecular cloud with the water molecules in these ice sheets around the dust grains.

[Interviewer/Moderator]

How did the whole thing finish up?

[Professor Stephen Eales]

I said at the beginning that the sub millimeter wave band was the last wave band to be really used for astronomy. And I kind of touched on the reason for that.

[Interviewer/Moderator]

And the reason for that is that

[Professor Stephen Eales]

everything in the universe emits sub millimeter radiation. So even detecting sub millimeter radiation is difficult because any instrument you build will emit submillimeter waves.

[Interviewer/Moderator]

And the only way you can avoid

[Professor Stephen Eales]

that is for the instruments to be very, very cold.

[Interviewer/Moderator]

Now, in the case of Herschel, the main way we kept the instruments cold

[Professor Stephen Eales]

was with this big, that here of liquid helium. And the liquid helium kept the instruments

[Interviewer/Moderator]

at about, I think, 300 millikelvin.

[Professor Stephen Eales]

So less than a 1 degree centigrade above absolute zero.

[Interviewer/Moderator]

So for the Herschel instruments were some

[Professor Stephen Eales]

of the coldest things in the universe, but the liquid helium container gradually running out of helium. And so we knew at some point the mission would come to the end

[Interviewer/Moderator]

because the soon as the helium ran out, what would happen is the instruments

[Professor Stephen Eales]

would immediately start to warm up and they'd be useless very quickly.

[Interviewer/Moderator]

So that eventually did happen and the instruments warmed up. Herschel was then useless, was at the second Lagrangian point.

[Professor Stephen Eales]

But then the European Space Agency are faced with the issue of what to do with it. Now, the second Lagrangian Point is really good for lots of reasons, but it's not actually a stable place to leave a telescope because

[Interviewer/Moderator]

if you orbit a

[Professor Stephen Eales]

second Lagrangian point, it's an unstable orbit, so anything at the second Lagrangian point will gradually move away from it.

[Interviewer/Moderator]

And so Iter knew this, and they

[Professor Stephen Eales]

had to think very carefully about what would happen to the telescope. Now, one possibility was it would eventually

[Interviewer/Moderator]

collide with the Earth, and there was

[Professor Stephen Eales]

the kind of hope that most of it would burn up in the atmosphere.

[Interviewer/Moderator]

But the problem was that the mirror

[Professor Stephen Eales]

of Herschel is made of very tough material and where people were pretty sure

[Interviewer/Moderator]

the mirror would not burn up in the atmosphere. Of course, the chances are it would

[Professor Stephen Eales]

hit the ocean or some uninhabited place. But you can imagine the public relations issue if Herschel had actually hit by the Trafalgar Square, for example.

[Interviewer/Moderator]

So, anyway, they rejected this idea pretty

[Professor Stephen Eales]

quickly, but there was still the big question, what to do. So here are the two other options. One option that was considered was firing it into the Moon.

[Interviewer/Moderator]

And the reason that was considered was,

[Professor Stephen Eales]

firstly, if it hit the Moon, it would definitely not hit the Earth. That was.

[Interviewer/Moderator]

That was a good thing. But the other possibility that came into mind was that if Herschel hit the

[Professor Stephen Eales]

Moon, it would throw up a lot of stuff from the collision, and then people could observe that and they'd find out more about what was, what was

[Interviewer/Moderator]

beneath the surface of the Moon. So that was an interesting idea. And the third possibility was the slightly

[Professor Stephen Eales]

more boring one, which is just try and send it into a safe orbit around the Sun.

[Interviewer/Moderator]

Now, this was seriously looked at.

[Professor Stephen Eales]

I didn't like it myself for a variety of reasons.

[Interviewer/Moderator]

I didn't like the idea of this

[Professor Stephen Eales]

kind of historical artifact just being destroyed.

[Interviewer/Moderator]

But apparently the reason it was eventually

[Professor Stephen Eales]

rejected was the ESA decided it'd be too expensive. It would cost money to actually do it. And they went for the cheap alternative

[Interviewer/Moderator]

which would send it into safe orbit. So it went into a safe orbit around the sun, but then, of course,

[Professor Stephen Eales]

it's still got power. So how do you turn the power off?

[Interviewer/Moderator]

Well, someone has to press the switch. And here is the moment at which

[Professor Stephen Eales]

Herschel was turned off.

[Interviewer/Moderator]

So this guy.

[Professor Stephen Eales]

So someone had a volunteer to turn this mission off.

[Interviewer/Moderator]

And this guy is a guy called Martin Kessler.

[Professor Stephen Eales]

He volunteered to turn it off.

[Interviewer/Moderator]

Here is the real picture of him turning it off.

[Professor Stephen Eales]

Soon as he did this, someone realized this was not a really good PR thing to do because you shouldn't really

[Interviewer/Moderator]

be smiling like a Bond villain as you do it. So they.

[Professor Stephen Eales]

This is a picture on the ESA website. Why do you want to turn it off? Well, I don't know if you leave the power on. I don't know if that has any effect on the orbit. This is one of the many things I don't know. Okay, so. So when I wrote this. When I wrote this book, I had

[Interviewer/Moderator]

to send it to the project scientist for Herschel and also Matt Griffin, who

[Professor Stephen Eales]

are the people that really knew the technical side. And they pointed out so many things I got wrong. It's amazing the number of things you get wrong. So I always say that Herschel was at the second Lagrangian point. It actually wasn't really. It was in a huge orbit around the second Lagrangian point. So there's so many things that are wrong.

[Interviewer/Moderator]

Anyway, the reason I wrote a book about it is that being involved in

[Professor Stephen Eales]

a space mission is so absolutely fascinating in terms of the things that happen.

[Interviewer/Moderator]

It's also, I think,

[Professor Stephen Eales]

quite nice because it's a. These are always international things. You know, we look at the news at the moment and the world is on fire. People are behaving like toddlers in the Middle East. But then you look at these things, you think, well, actually, this mission was a mission of at least eight different countries involved. And everyone got on and everyone actually, I mean, there were moments when they didn't, but everyone managed to actually communicate. So I think in a way it's a. It's a nice thing to think about this and to.

[Interviewer/Moderator]

In astronomy and science in general, there

[Professor Stephen Eales]

are all these amazing. You know, it's like the opposite side of humanity from the Donald Trump side, I would say, which I think why. Is one of the reasons why Trump

[Interviewer/Moderator]

has not actually said much about Artemis.

[Professor Stephen Eales]

Because he doesn't like this kind of thing.

[Host]

Especially because they had radio silence when you spoke.

[Launch Commentator 1]

Brilliant.

[Professor Stephen Eales]

Oh, did he?

[Host]

Yeah.

[Professor Stephen Eales]

Anyway, thank you for your attention. I have copies of my book if anyone wants to buy it.

[Interviewer/Moderator]

I have a card machine as well, if anyone wants to.

[Professor Stephen Eales]

And I will sign it. Anyway, thank you. Forget about buying the book.

[Interviewer/Moderator]

It's been great to talk to you.

[Professor Stephen Eales]

Thank you.

[Host]

All right, thanks very much, Steve. Who's got questions for steep with missions like.

[Audience Member 1]

Ah, that's better. Ingenuity and curiosity. There's. There's always like, spare a second module that stays on Earth so that they can like run test and stuff.

[Professor Stephen Eales]

Yeah.

[Audience Member 1]

After. If a launch goes bang.

[Professor Stephen Eales]

Yep.

[Audience Member 1]

Is there a process in place where they can go, let's quickly get the second one into orbit and do that and the second question is, is there any tool of at the end of the Herschel mission where they put in a safe orbit around the sun where they might have another lot cheaper instrument that they could use to maybe observe the sun to bring that into play?

[Professor Stephen Eales]

Well, answering the second question first, I don't think there was anything really left on the spacecraft they could use to do anything useful. The first question is an interesting one because this actually did happen. There was an issue with this because there were three instruments on Herschel, and on day 82, one of the instruments died. So there was an instrument called hi Fi and a diode blew out on day 82 and they had to turn it off. And as you say, they had a spare set of electronics on the ground. So there was a spare set in orbit actually in the instrument, but it didn't want to turn the spare set on board on because they thought the same thing might happen again. And they thought maybe they just designed it badly. But by a lot of careful tests, I mean, this must be traumatic for the team. I mean, I didn't care. I wasn't involved in that part of the mission. But it must have been really bad. But for about six months they were trying to figure out what had gone wrong. And eventually they figured out that there had been a programming error in hi Fi. They'd done this using the stuff on the ground, and they reprogrammed hi Fi and then turned it on again and it then worked. So all the stuff on the water that I mentioned was done with hi Fi. So, yes, you're right. There's always spare sets of instruments on the ground.

[Host]

What was the second part then?

[Professor Stephen Eales]

It was about, oh, if the launch went bang, If the launch. I don't know. What if Herschel had blown up on launch? Herschel and Planck blowing up on launch. I think what would have happened next would have depended on politics and money. Because in the case of the one that did go bang in the early 1990s, which was the mission cluster, they did send the subsequent. They did send cluster 2 up to replace it, but I'm not sure what the financial situation was. No. In 2009, one year after the world financial crisis, I have a feeling that would have been it.

[Audience Member 3]

Two questions.

[Audience Member 2]

A lot of projects like this generate

[Audience Member 3]

an awful lot of data. So has that data, has all the data been analyzed and have not how

[Professor Stephen Eales]

long this is going to take?

[Audience Member 3]

And the second question is, did the Belgian team still write the software for the rocket launch?

[Professor Stephen Eales]

Well, I don't know about the Belgian Team. But the answer to the first question is, yeah, all the data taken by Herschel is in an archive and astronomers like magpies. Because what happens is you have an idea for a project and you do the observations and often by the time you've done the observations, you've lost interest in it. Do something else. So there's a lot of observations in the archive that haven't been looked at yet. I mean, probably most of the really good stuff has been mined. But one of the things we often do nowadays with these big telescopes is it's often more cost effective. Rather than writing a proposal to use, do a new observation. Often what you end up doing is you end up going for the archive looking for cool data that's never been looked at before.

[Audience Member 3]

The reason I say that because I have seen images of. I have seen images where they're combining data from different missions and different wavelengths. The one of the Andromeda, you've got the optical.

[Professor Stephen Eales]

Yes.

[Audience Member 3]

Tells you where the stars are that we can see today with the sub millimeter showing where the stars are being formed and with the X ray data showing where the stars have died. So, you know, even though that data may have been processed, it's still, still useful to the scientific.

[Professor Stephen Eales]

No, that's what we, that's basically a common thing we do nowadays, which is you take the data from all the. So there's always different wave bands. Every time you look at a different wave band, things look different. And you know, the standard thing people do nowadays is we kind of combine the. We've actually done a PhD thesis. You combine data from different wave bands and you.

[Host]

Yeah, yeah, yeah. So my entire PhD was archival data from different missions. So. Yeah, yeah, right. Any more questions? All the way at the back, Paul. There's always one, must be two now, right?

[Professor Stephen Eales]

Hang on, you said that crashing the scope into the Moon cost money. How exactly would that cost money? Instead of just like pointing at the moon and going go well, okay, I'm never entirely sure what the grounds were for that, but I think the issue is that if you crash it into the Moon with the idea that you're then going to do what you're going to observe the plumes of material that are sent up. As soon as you start doing that, you have to actually factor in the people you're paying to. There's always a cost to keeping things going, having the scientists continue to work. So I think that was all it was, is they would have had to pay for the scientific exploitation of it.

[Host]

Any more. For any more. Oh, yeah. Oh, there's, there's one. All right, we'll go this side.

[Audience Member 1]

Yeah.

[Professor Stephen Eales]

You said it's a, it's a space mission because the water in the atmosphere precludes observing in this submillimeter wavelength from Earth. Yes, but later on you also mentioned the Atacama submillimeter thing. So that's a good question. So the submillimeter, I mean, I skirted over a few things. So the sub millimeter wave band, there are a few atmospheric windows, so there's a few small ranges of wavelength in which you can observe from the Earth. So the pictures I showed of the Hubble Deep Field were taken with a camera on the ground in one of these atmospheric windows. Now the radiation from the water is at certain spectral lines and those are almost always in the way, the wavelengths that the atmosphere is opaque. So it's a little, the Atacama Large Millimeter Array observes in these spectral, these atmospheric transmission windows.

[Host]

Right. And then there was a question over on the right.

[Audience Member 2]

So during the conversation about the dust in the galaxy, you were saying that most of the dust was illuminated in the blue because most of the stars were blue stars. Does that indicate that after initial creation, most of the stars in the Galaxy are large mass stars rather than small like the K's, F's and G's?

[Professor Stephen Eales]

No, it's a little bit complicated. It's because the, again, I kind of skated over stuff. So when a population of stars form, the most massive stars are the most luminous stars and they tend to be blue and they tend to dominate the light, but they're also short lived. So if you have a region in which stars are forming, you have all these short lived stars dominate the light, so the blue stars dominate. There are actually plenty of red, low mass stars there. You just can't really see them.

[Interviewer/Moderator]

So in the case of Andromeda or then the other thing is that the, when the stars form, they eventually leave their clouds.

[Professor Stephen Eales]

So the disk of Andromeda appears quite blue because some of the blue stars have emerged from their clouds. But most of the young stars are still in the clouds, so you can't see them at visible wavelengths.

[Interviewer/Moderator]

One of the interesting things actually is

[Professor Stephen Eales]

I've been looking at pictures of Andromeda taken by amateur astronomers recently, and you can see much more clearly some of the same structure that we see in the sub millimeter. So in the sub millimeter we see these, these kind of filaments and braids. In Robert Gendler's picture, you can't really

[Interviewer/Moderator]

see it particularly well, but some of

[Professor Stephen Eales]

the latest pictures you can see in the visible, you can see these dark bands that correspond to where we're seeing sub millimeter emission. The other thing I should say is that if you remember the two pictures of Andromeda, our beautiful sub millimeter picture and Robert's picture taken with his 16 inch telescope, the Daily Mail picked up on this and they made the point that our Herschel picture had cost European space mission cost a billion euros and this avatar had bought one which is much better. So I felt quite proud of being sort of targeted by the Daily Mail at that moment.

[Audience Member 2]

So there was one last part to this was SN1987A generated a lot of dust in the, in the very first stars. In the absence of any dust, how do the stars form if they haven't got the dust to shroud the initial cloud collapse?

[Professor Stephen Eales]

Well, that's a, that's a fundamental, a fundamental question. So, so most of the stars, with all the stars we see contain heavy elements. These are oxygen and silicon and that changes even apart from the dust. The existence of these heavy elements changes the way stars form. But you're absolutely right, the first stars in the universe that would have formed would have been formed basically out of hydrogen and helium. And these stars are often called population free stars. And the thought, I can't remember exactly details, but I think theory suggests they should be really quite big. And one of the reasons for the James Webb Space Telescope that was launched a few years ago, the idea was you'd hope to see these stars. They haven't really seen these stars, but they've seen very young galaxies. So the absence of dust, the absence of heavy elements changes completely how things operate.

[Host]

Right then I think we'll have to call questions there, but let's give Steve a round of applause again.

[Show Producer/Closing Announcer]

Awesome Astronomy is produced by Ralph Paul, Jen, John Damian and Dustin and is free to use with attribution. Theme music by Star Soulsman with stinger variation by Rin Jorgensen. We promote general science, astronomy, space exploration and rational thinking with more resources on our [e-mail] if you want us to read your thoughts and comments out on the show. Send us your views, opinions, critiques or questions to the [e-mail] tweet us @awesomeastropod or give the awesome Astronomy Facebook page a like and leave your comments there. Thanks for listening. From Cydonia Base Head of Transmission.