Planetary Radio: Space Exploration, Astronomy and Science - Exploring the XDF, The Deepest Image of Our Universe, With Garth Illingworth

Episode Date: October 8, 2012

UC Santa Cruz astronomer and XDF Principal Investigator Garth Illingworth takes us on a tour of this magnificent new image.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

The Deepest Ever Snapshot of Our Universe, this week on Planetary Radio. Welcome to the travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. It's called the Extreme Deep Field, and it took 10 years of Hubble Space Telescope images to create it. Astronomer Garth Illingworth is here to tell us more. Bill Nye is on his way home from the International Astronautical Congress in Italy. He'll rejoin us next week. But Bruce Betts is here as always, this time to help me give away a telescope.

And we're also joined by Senior Editor and Planet planetary evangelist, Emily Lakdawalla. Emily, great to have you back with another update on Curiosity. The particular entry that I'm looking at was from the 4th of October, and Curiosity staying very busy 60 or so days into its mission. Yeah, and of course, it's kind of surprising to people that the pace of this mission is, it's both fast and slow in a way. They've already driven 400 meters, and yet they haven't finished commissioning all the instruments. And that's the activity that they're working on right now, is they are doing their very first ever scoop sample of soil from this sand drift called Rocknest. Before that sample was taken, and it may have been taken by the time people hear this show, check the blog and you'll be able to see Emily's report on it. It had pulled up to this

little tiny drift, tiny sand dune, and left a footprint. That's called a scuff, and it's something that all previous rovers on Mars have done. Basically, all you do is lock five of the wheels and rotate the sixth one to see what happens, what the soil looks like underneath the ground. And I don't think there are any surprises there. It's darker underneath the surface than it was on the surface, and that's true generally on Mars. You brush away the bright dust and you get to darker soil. And there is a very cool before and after showing this little undisturbed sand dune that probably was sat that way driven only by the wind for a long time, having it

getting disturbed by this creature from Earth. Just below that is this very cool image of the instruments on the arm moving right over to that spot. Yeah, and of course, there are now images on the ground from the MOLLE. That's the microscopic imager on the end of the arm. And the thing that struck me most about that is that so Mali looks very, very closely at the sand grains. And they're nice rounded sand grains, which is what you often get in this kind of Aeolian environment. But even the sand on Mars has dirt on it. There's like this dusting of dirt on the sand. And so that it kind of explains why

everything on Mars looks like the same color. As soon as you brush underneath that, you find different color materials. Why did you refer to the surface as being armored? Well, if you look at the sand dune before it was disturbed and then after it was disturbed, there are these round sand grains. I don't know precisely the scale, but they're less than a millimeter across, but more than a nanometer across. But there are these round sand grains, and they're all sitting on top of the dune. But as you look underneath it after Curiosity scuffed it, the soil that's underneath those grains that are on the top of the dune is very, very fine,

which is precisely the kind of material they were looking for to do their first soil scoop. But what that means is that you had this surface that used to have these larger grains moving around. And I don't know if the weather has gotten less extreme or what, but now you only have finer material being moved. And what you have left on the surface is a lag deposit. It's material that the wind no longer can move, but the finer stuff has kind of been blown away from around it. And so you're left with this layer of slightly larger grains sitting on top of a dune made

of finer stuff. People can learn more at planetary.org and see these blog entries right there as well in Emily's blog. Thanks so much. Thank you, Matt. She is the senior editor for the Planetary Society and our planetary evangelist as well. Up next, astronomer Garth Illingworth with the extreme deep field image of our universe. You've very likely seen the Hubble Ultra Deep Field, or UDF. It's an iconic image of a small slice of night sky that looks back through thousands of galaxies and billions of years.

Now the UDF has been superseded by the even more spectacular XDF, or Extreme Deep Field, that relies in part on the upgrade of the Hubble Space Telescope a couple of years ago. UC Santa Cruz professor of astronomy Garth Illingworth served as principal investigator or leader of the UDF-XDF project. He recently joined me from his campus office via Skype. Garth Illingworth, thank you very much for joining us on Planetary Radio and for sharing this wonderful, this really stunningly beautiful new work with us, the XDF. I have told our audience in the past that I have hanging behind me a lovely poster of the UDF. I guess I'm going to have to change that out now.

Yes, and thank you very much, Matt, for inviting me on the show. I'm delighted to be able to do this. Yes, the UDF was done in 2002 and released in 2004, so it's approaching eight years old now. And we realized late last year that there's so much more data around that we can make a wonderful, new, much better and deeper image. And so that's what we did. We decided it was so much better and deeper image. And so that's what we did. We decided it was so much better and different that we decided we should call it the Extreme Deep Field, XDF. So my poster now is obsolete.

I'll take care of that. I can assure you that many of the galaxies are still there. Actually, most. That's good. It's good to know they have a long lifespan like ours. What did it take to create this image? It was a surprising amount of work, partly because we have so many diverse programs

that have taken data on this field. The Ultra Deep Field itself, the Hubble Ultra Deep Field from 2003 was the deepest, but we then took some very deep images with a new infrared camera in 2009 and 10. But there are, in fact, another 10 programs that have made images in this region that have overlapped with Hubble Ultra Deep Field. And so we had to take all those and put them together. And they were different orientations, different positioning, different filters. So it took many months of work to put this image together.

And it's not as if you were able to point the Hubble at this tiny patch of sky continuously. I mean, that just would be prevented by the fact that the Hubble is orbiting the Earth, right? But there were other challenges, too. Yes, certainly. You know, so much a challenge as an opportunity here that with two different cameras, we were able to extend the wavelength range into the infrared that we could take many different data sets and combine them. has been taking data on this field. It's actually pointed at this region for 50 days in total, and during that time built up an exposure of 2 million seconds. So it's a pretty long camera exposure. I'll say.

We're going to come back to the importance of that infrared element in this image and future images to come from other instruments, but I called it a tiny patch of sky. Just how much of the sky is captured in the XDF? You're exactly right. It really is tiny. If one looks at the full moon, it's about less than a tenth of the size of the moon. So it's, in fact, about 1% of the area of the full moon, which is very small.

But that's the only way that we can really build up a huge data set. The cameras on Hubble, while they have such good resolution, also aren't that large. So the area that you get is only a few arcminants on its side. In this tiny space, how many galaxies have you counted? In this one, 5,500 roughly. And so it depends on the limit one set. That's a very reasonable number for galaxies that go from just a few billion years back in time right back to almost the earliest times we can do, 13 billion years ago. It would be a major error to think of this image as having anything to do with just two dimensions. In fact, on a website, which you've kindly provided, and we will post as a link

on the page where people can find this show at planetary.org slash radio, there is a really beautiful animation that allows us to fly right through the XDF, back toward the beginning of our universe. Yes, that's exactly right. That was an excellent idea by the folks at Space Telescope Science Institute. We developed the image, and they suggested doing a fly-through.

And so we went back and found redshifts, got distances basically for all the objects in there, all the galaxies, and gave them that information, and they set up the fly-through. And they did a beautiful job on that, as you said. Absolutely. Is it accurate to say that when we look at the XTF, we're looking at a picture of not all, but nearly all, of the universe's history? You know, this is a wonderful way to think about it. I think that, you know, in this single image, in many ways, it has encompassed the history of the buildup of the growth of galaxies from almost the first galaxies until almost the current day. So it's absolutely astonishing that one can look at an image there. these different times, different shapes, sizes, and think, wow, we can go in there and learn a huge amount about how galaxies have grown during the whole life of the universe.

Different shapes and sizes. Are we also looking at different ages? Are there both, you know, infants here and senior citizens? Exactly. Yes. If you look at the, the listeners go and look at the image and look at the bigger galaxies, you'll see blue galaxies like our own Milky Way many billions of years ago, but very similar, and big red galaxies too, like the big galaxies in the Virgo cluster, which are full of old stars. So there are galaxies that have aged very differently in this image. I hope this isn't throwing you a curve, but here's something that just occurred to me based on that statement. When we see a galaxy that looks a lot like ours, the Milky Way, except that we're looking back billions of years, does that tell us something about how galaxies evolve and how quickly that takes place? Very much so. Very much so. That's one of the key scientific features or outcomes of looking at an image like this

and many of our other deep images of the universe is that we're trying to understand how galaxies built up from the tiny little infant seeds, which were 1% of the mass of the Milky Way, a 20th the size, into the magnificent spirals like Andromeda that we see so clearly today. There are also these big red globular structures, not to compare them to, you know, globular star clusters, but I don't know, maybe there is some similarity there. What do they represent? Are those also galaxies? Yes, they certainly are. They're the galaxies that astronomers call elliptical galaxies. And these are galaxies where they really have almost entirely completed all the formation of their stars.

The stars are aging, old, not doing very much. They're magnificent objects, but very simple and sort of basic to look at, but not, of course, simple in their structure and dynamics. More from astronomer Garth Illingworth about the Hubble Extreme Deep Field is just ahead. This is Planetary Radio. Hey, hey, Bill Nye here, CEO of the Planetary Society, speaking to you from PlanetFest 2012, the celebration of the Mars Science Laboratory rover Curiosity landing on the surface of Mars. This is taking us our next steps in following the water in the search for life

to understand those two deep questions. Where did we come from? And are we alone? This is the most exciting thing that people do. And together, we can advocate for planetary science and, dare I say it, change the worlds. Hi, this is Emily Lakdawalla of the Planetary Society. We've spent the last year creating an informative, exciting, and beautiful new website.

Your place in space is now open for business. You'll find a whole new look with lots of images, great stories, my popular blog, and new blogs from my colleagues and expert guests. And as the world becomes more social, we are too, giving you the opportunity to join in through Facebook, Google+, Twitter, and much more. It's all at planetary.org. I hope you'll check it out. Welcome back to Planetary Radio. I'm Matt Kaplan. We're looking backward more than 13 billion years. That's the visual history revealed by the just-released Extreme Deep Field, or XDF, image. It builds on the earlier Ultra Deep Field, according to principal investigator Garth Illingworth. You also sent me a fascinating graph that seems to say that we may be seeing about as far back in the XDF as we're going to be able to see with the Hubble.

Why is that? That's a very good question. So Hubble, in 2009, the astronauts took up on the space shuttle a new camera, the new infrared camera, Wide Field Camera 3. And that has several filters in there that go out into the near-infrared past where our eyes can see, but not very far out. Now, with the redshift of galaxies, as the universe expands and we look at greater and greater distances, the light gets shifted further and further to the red. And the hydrogen in the universe is absorbing the ultraviolet light. So there's sort of a funny confluence of events here, wherein galaxies eventually just disappear from view. And unfortunately for Hubble, the Redis filter only allows us to go back 13.2 billion years, roughly. And the universe is 13.7 billion years old.

So you can see we're getting very close to the Big Bang, but not as close as we would like to be. But unfortunately, Hubble is reaching its limit with these new images with its infrared camera. So Hubble reaching its limit, but it used to sort of faintly bother me that this next great telescope that so many of us and people like you are looking forward to, the James Webb Space Telescope, it's going to be an infrared instrument. And I think maybe I begin to understand why it is infrared rather than visible light. Exactly. Matt, you've got it exactly right. I think even when we first held our first scientific meeting on this that I organized with a couple of other folks at Space Telescope Science Institute in 1989, before Hubble launched. We were thinking already that we needed

to be able to go further into the infrared to see the earliest galaxies. And so the first galaxies, invisible to Hubble, but not invisible to James Webb. So this is one of its great quests is to search, to explore back amongst the time of the first galaxies. Well, how far back then do we expect the JWST, much larger, improved instrumentation, improved cameras, how much farther back into that half a billion years might it be able to take us? It's a tough question because we really don't know when the first galaxies occurred and the first stars. But I think in round numbers, we're hoping it'll take us back about half the distance of the Big Bang,

right around the time of the first galaxies and stars, which our model suggests now probably are two to three hundred million years after the Big Bang, somewhere in that time frame, so a couple of hundred million years. Before that was the Dark Ages. There was nothing visible in the universe in the way of stars or galaxies. And then the first stars and galaxies turned on. And our hope is that JWST will take us back into that incredible, interesting beginnings of galaxies. What is your ongoing role with the JWST, which, of course, is still being pieced together? I was the scientist member of a major committee put together by the NASA administrator two years ago when the serious budget problems with JWST were becoming apparent to all.

And we suggested a new path forward. And I would say that NASA picked up on that and ran with it and did an amazing job of putting together a revision to the program. It costs more, but I have a great deal of confidence that the current schedule of 2018 and the current budget will enable JWST to be launched on budget and on schedule. NASA has been very responsive to the recommendations of that committee. From what I have read, there were these budgetary and management problems, but the technology seems to be coming along swimmingly.

Swimmingly is probably, this is cutting-edge technology. And I would say that the folks involved in the technical details, which I'm not, are doing an amazing job of meeting their milestones and of accomplishing what they need to do. But, boy, this is tough. This is the first time we've ever done many of these, used many of these technologies, and they are right at the cutting edge. And so this is a stunning demonstration of a remarkable use of technology, but it sure isn't easy. And I'm always on the edge of my seat, as it were, watching and hoping that everything moves smoothly from here on out. Garth, we will wish you and your colleagues an undelayed first light from the JDBST. And thank you very much for this very beautiful image from the Hubble Space Telescope.

Thank you, Matt. It was a delight talking to you. And thank you for your great questions. You are very welcome. Garth Illingworth is professor in the Department of Astronomy and Astrophysics at UC Santa Cruz. He is also an astronomer at the famous Lick Observatory, operated by the University of California. And speaking of the Space Telescope Science Institute, he was its deputy director from 1984 to 1987. I'll be right back to talk with our own house astronomer, Dr. Bruce Betts, for this week's edition of What's Up in just a few moments. Let's give away a telescope.

Hold your horses there, partner. We're not ready for that. I can't hold them. That was terrible. I can do the voice better than that. He's Bruce Betts, the director of projects. We only call him the Duke around here. And it's time for What's Up.

So anyway, I looked in the night sky and there were planets you can check them out too low in the west shortly after sunset you can still pick up mars and in fact reddish mars is getting closer and closer in the sky to reddish and terry's the red giant star and they'll be growing closer through most of the rest they'll at least be close through most of the rest of October. And Terry's the star is the one over to the left and then lower down later in October. They're similar in brightness. Rising around 10 p.m. or so over in the east. Super bright for the rest of the night. Jupiter is hanging out near the moon on October 12th.

No, no, it's not. No. It's not? Why did you tell me that? Did you pin this on me? Pre-dawn, it's hanging out in the east with Venus. It's done with Jupiter. It's moving on.

Moving on. Moving on to Venus. Okay. Speaking of moving on, we both leapt at that segue. On to this week in space history. Three years ago, LCROSS slammed intentionally into the moon. Wham!

Wham! And it might have made that noise. 65 years ago this week, it's not quite space, but it was getting us there. Chuck Yeager breaking the sound barrier. We move on. We move on to Wait a minute. Wait a minute. Wait. Wait. That's a great opportunity to do it again. Wham! That was the sound barrier being broken. Oh, wow. Wow. The thematic. I'm so brilliant with connecting these things. I don't even realize it

sometimes. It takes your amazing sound effects to bring it all together. It's just good radio. Speaking of good radio, we move on to... Ram! Dung! Space! Back! That was cheery.

The location Mars Rover Curiosity is exploring right now, it's just reaching or will be reaching over the next few days. It's called the Glenelg area. Glenelg, named first of all because they're naming pretty much all the areas after places in the northwest territory of Canada, in the Yellowknife region, and there's a place called Glenelg. There are also lots of other Glenelgs in the world, it turns out. But the reason they picked it for this particular location, because it's a palindrome. It is the same spelled forwards and backwards.

And they thought that nice symbolism because they're actually going the wrong direction compared to where Mount Sharp is. And they actually did this accidentally because, of course, they're not going to ask directions. And so now they're just pretending that's what they meant to do. And so they'll go to Glenelg and then they'll drive back past Glenelg. So Palindrome forward, backward. It's the same.

Most of that story is true. Yeah. Really? I really think this is the only reason these guys go into this business, because they can give things silly names. It is. What's impressive to me is each mission, they come up with some new

silly way to name things. I did not know that was the naming convention. Alright, you can saddle up your horses now. This is our opportunity to give away the Celestron First Scope Telescope from our good friends at that company. We started this at the PATS conference when we gave one away to somebody in the audience. And here's the one that we

saved for you folks, the listeners out there. What was the question? And thank you once again to Celestron. The question was, as of September 20, 2012, how many near-Earth asteroids have been discovered to within 100 or 200? Since the numbers keep changing, we'll be slightly flexible, but not that much. We had almost double the normal response for this. Not surprising, because how often do we give away a pretty cool little telescope. From among all of those, random.org selected Ethan von Zandt. Ethan von Zandt,

we don't have to pay much for postage. He lives in Santa Monica, California. Only, what, about 35 miles from here, something like that. Ethan said that there were about, there are about 9,100 near-Earth asteroids discovered so far.

There were a few people who said, quite a few, who said 8,800, which must be the current number in the Wikipedia. But a lot of people got this number off the JPL site. Other slight variations, close enough. Close enough. I looked on that very day, and there were 9,091 listed on JPL's NEO site. Well, Ethan, congratulations. You've picked up that first scope. And now we're back to giving away T-shirts. And there were 9,091 listed on JPL's NEO site. Well, Ethan, congratulations.

You've picked up that Furscope. And now we're back to giving away T-shirts. But we have a special one to give away. Oh, I should mention, we didn't get very many silly answers for this one. And I don't know if you could call this silly, but Michael Clark in New Jersey, he did mention that there are about 23,000 nuclear warheads in the world. So we have almost two and a half nukes for each near-Earth asteroid. That is a random space fact. All right, on to the next trivia contest.

Emphasized to me when I just attended the MEPAG meeting, the Mars Exploration Program Analysis Group. Exploration Program Analysis Group. What is the first name of the principal investigators for each of the next two Mars missions? The next two missions going to Mars. What is the shared first name of both of the principal investigators of those missions? Go to planetary.org slash radio. Find out how to enter, and we'll be giving away what, Matt? This T-shirt, which you found in your office.

Boy, that makes it sound appealing to people. No, this is a great shirt. It is a great shirt. I'm going to keep one of these for myself. I'm admitting it right here. It's from chopshopstore.com, and this one is specifically for the Planetary Society. Your Chop Shop store, if you happen to go there, buying one of these shirts actually benefits the society somewhat.

But this is a really cool one that has these silhouettes of a whole bunch of solar system exploring spacecraft on the front. Indeed. All out at the orbits of where they were exploring. This is a really cool shirt. It is a cool shirt. Go to planetary.org slash org planetary.org slash radio

find out how to enter. When do they need to get that in by, Matt? By the 15th. Monday the 15th of October at 2pm Pacific time. We have one more thing to mention. We do. Do you know that this show turns 10 next month? I cannot believe that. Isn't it amazing? We've been discussing

that, but it's shocking. Hundreds and hundreds of episodes. Well, we're going to celebrate, and we want to give you folks out there a chance to help us with this celebration. We're calling November 12 that week. The show that opens up for that, that is available that week, is the anniversary

show, and you can participate. We hope you will. If you'd like to leave us a message, now we won't be able to use all of these on the air, but if you want to leave us a message or say random space fact or something like that, give us a call. You're going to call 626-793-5100 extension 226, and you'll hear my friendly voice inviting you to leave us your message about the 10th anniversary of Planetary Radio. That's country code plus one. That's true.

But wait, there's more. There's more. If you go to planetary.org slash radio, those of you who want to get fancy, there will be a link there. There is a link there. If you want to upload an MP3, now and then people get really fancy and give us some really cool audio. Yeah, we've had some really amazing things. Yeah, it can be random space fact. You can come up with a little ditty, a little tune if you want.

Send us what you like, audio only. It's a radio show, folks, radio show podcast. Actually, you'll just be able to attach it to planetaryradio at planetary.org, the same one you sent to to enter the contest. But there's more information at planetary.org slash radio. All right, everybody, go out there, look up at the night sky, and think about why are there not more boysenberry things in the world? I need more boysenberries and more boysenberry treats. I'm with you.

I love boysenberries. I also like blackberries very much. That's not helpful. Blackberries are everywhere. Boysenberry. Do you know who invented boysenberries? Uh, Walter Knott. Yes, that is correct. I got it. Do I get a shirt? Yes, you do. The shirt I'm wearing. Here, take it.

Please don't take it off. He's Bruce Betts, the Director of Projects for the Planetary Society, who joins us each week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California and made possible by a grant from the Kenneth T. and Eileen L. Norris Foundation and by the members of the Planetary Society. Clear skies. Thank you.