Planetary Radio: Space Exploration, Astronomy and Science - The Eyes of WISE Deliver Sky Survey Prize

Episode Date: July 26, 2010

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The eyes of WISE find thousands of new asteroids this week on Planetary Radio. Welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. Principal Investigator Ned Wright returns to share with us the wonders just revealed by the Wide Field Infrared Survey Explorer, or WISE. Bill Nye is ready to set sail on the lakes of Saturn's moon Titan, and Bruce Batts will brief us on a very busy night sky during What's Up. Also very busy last week was Planetary Society blogger Emily Lakdawalla, but not so busy that she couldn't show us a robot named Curiosity taking its first steps.

Emily, welcome back. Much to cover this time, so we're going to jump right in. I love watching that new big rover actually rove across the lab at JPL. It's really astonishing how huge Curiosity is. It is so much bigger than the Mars Exploration Rovers. And seeing it move for the first time was kind of a thrill, but it was definitely just its first baby steps, a little bit of forward and backward driving, not more than a meter or two in each direction.

Yeah, it was fun. You've got all these parents standing around it, helping it take its first few steps, and it has a tether. And anyway, speaking of Mars, that map that you got so excited about actually brought you to tears. Yeah, I'm a nerd, but it's true. It really, I got a tear in my eye when I was looking at this map, because, you know, it's the product of nine years of work by this mission, just patiently orbiting Mars 12 times a day, capturing these images and then sending them back to Earth. And then nine years of work by all the

people back on Earth to carefully assemble all these images into a seamless map that covers the vast majority of the surface of Mars. There's still a couple of data gaps here and there. And fortunately, Odyssey is still alive and kicking and is taking images at very high priority to cover those gaps. But it's the most beautiful map of all of Mars you've ever seen. And we should say specifically, this is from the Themis infrared instrument. That which we have spoken to Phil Christensen about a few times may have to have him back. Absolutely. And thermal infrared is very different from visible light, even though the images look like photographs because they were taken in the afternoon. And because of that, the surfaces that warm up in the sun during the day appear bright.

Surfaces that were shadowed during the day appear dark. And so it has the same kind of topographic shading that a visible light image does. But there's so much richer information in there because also dust warms up more than rock does during the day. So dusty areas appear bright and rocky areas appear dark. So there's a lot of geologic information encoded in this map. And I want to warn people that when I first looked at it, I thought, she's that excited about this? And then I started zooming in and zooming in and zooming in and zooming in, and it is really mind-blowing. So check it out on the blog, folks. We'll put the link up. Three more quickies. Dancing ring particles.

These, I can't even begin to describe it, but when Prometheus dives in and out of the F ring, it creates these stunning patterns in the rings. You've just got to go to the blog to see the animations. They're gorgeous. It's incredible to watch. I was actually thinking of a little bit of a waltz as I watched them go. Blue Danube, I think. Two more for online folks. Beginning with Facebook, you had a notice to put up to your friends. That's right. You know, Facebook, I think people have a love-hate relationship with Facebook. I've been struggling with what to do with, yeah, I've been struggling

with what to do with my professional page. And finally, I realized that I needed to convert it to what used to be called a fan page. So now you can go to my page, Emily Lakdawalla, author, and you can like me. Please like me. I absolutely hate the emotionally laden terminology on Facebook, but we're stuck with it. So yeah, go search for Emily Lakdawalla, author, and you'll find me there.

You can hit the like button at the top, and you can follow my blog and any other comments they may have about what work I'm working on that day. And surprise for me, these new network blogs, and it's one more way to follow Planetary Radio as a podcast. So you can check that out as well. There's a reference to it in Emily's blog entry. And finally, you asked me to save 15 seconds for something that you

and I guess a lot of other online people are pretty excited about. That's right. I just want to wish everybody a happy StarCraft 2 release date on July 27th. I know what I'll be doing that day. I'm not sure if you should expect a blog entry. Except maybe one about StarCraft. Emily, thanks again so much. Thank you, Matt. Emily Lakdawalla is the Science and Technology Coordinator for the Planetary Society and a contributing editor to Sky and Telescope magazine and apparently a devoted player of Starcraft. Watch for her and listen for Bill.

Hey, hey, Bill Nye, the planetary on Titan, the largest moon of the planet Saturn. There's a lake on the moon of Saturn that using radar on the Cassini spacecraft, scientists have determined that the lake is getting smaller as summer goes into fall. In other words, they're measuring the depth of a lake on another world. And this lake is not made of water, my friends. This lake is made of methane and ethane. That is to say, it is made of natural gas that's so cold. How cold is it? It's so cold, it's a liquid. And the radar can see through the liquid to a few meters down, a few tens of feet down. And you can see the lake bottom on Titan, which is in orbit around Saturn, which is in orbit around our sun. This is astonishing. The year of Titan, if you were a Titan dweller, takes about 29 1⁄2 Earth years.

So looking at radar data over the last four years, people have figured out that some of the lake is evaporating, just like a lake on Earth, except it's made of clear natural gas. They've got bathymetry, depth measurement, on Titan. This is the kind of thing that can change the world. Now, my friends, imagine this. Suppose we built a spacecraft that was a boat, and it went to Titan and floated around on a lake of methane and ethane. How cool, or if you will, how cold would that be? This sort of thing is just exciting. The same way we explore the Earth, we are using the same techniques to explore this other world.

And you know what we're going to find out by exploring the other world? Nobody knows. That's why we're exploring. I've got to fly Bill Nye the Planetary Gun. NetWrite first joined us last December, right after the launch of the Wide Field Infrared Survey Explorer. Barely a half year later, WISE has imaged an astounding array of asteroids, comets, and brown dwarf stars never before seen. These include a nice assortment of near-Earth objects, those space rocks that ominously cross the path of our planet. It will take many years for other telescopes in space and on the ground to follow up, and that's exactly the predicament WISE was supposed to put astronomers in.

In addition to being this mission's principal investigator, Ned holds the David Saxon Presidential Chair in Physics at UCLA, the University of California, Los Angeles. That's where I found him a few days ago. Ned, it was just last December that we last spoke. A lot has sure happened with the WISE mission since then. Congratulations on the completion of this first sky survey. Yes, well, we launched in mid-December, and by the middle of January, we were observing the sky very systematically. And then in six months, as the sun goes around the sky, or you could say the Earth goes around the sun, following Copernicus,

we have mapped the entire sky. Truly amazing that this could be done in the kind of detail that WISE has examined this guy. It was only a couple of weeks ago that we had Bill Berucki on this show talking about Kepler's results, the discovery of what may be hundreds of new exoplanets. Now you guys come up with the discovery of thousands upon thousands of new asteroids, some of them near-Earth objects that could pose a hazard to this planet. That's right. WISE is sensitive to room temperature objects because it's looking at infrared radiation that's radiated by room temperature objects.

And asteroids, since they sit in sunlight, are approximately room temperature, sometimes a little colder and sometimes a little warmer. As a result, WISE is a very sensitive asteroid. So we have seen about 130,000 asteroids. Not all of those are new, but over 25,000 new discoveries of asteroids and 100 near-Earth objects that we've discovered. You know, one thing that I should definitely point out is that in the current year, while WISE is operating, many hundreds of near-Earth asteroids have been discovered, not just by WISE, but by many other observatories, like the Catalina Sky Sky Survey working in the ground in optical light.

And so WISE is finding about 25% of all the asteroids, the near-Earth asteroids, that are being found this year. Still awfully impressive. Does this say to you that we are in what I'm thinking of as a golden age of space-based astronomy? Well, we certainly have a lot of space missions operating now and under construction that are providing data on many new wavelengths. So we're getting a much better view of the universe. In my thinking, discovering 100 objects that this planet needs to be aware of for self-preservation reasons is pretty impressive. You know, we talk to a lot of neo-discoverers, and in my opinion, any one of them could be saviors of humanity.

So I should thank you for that as well. Well, so far we don't know of any that we found or anybody else has found that are actually predicted to be a major hazard. So it's important to get a catalog of all of them so that we'll know that we don't have to worry about them immediately. Certainly the most important thing for protecting the Earth from an asteroid strike is lead time, warning time. Further ahead, we know that there's a problem, the better off we are. So in addition to all of these asteroids, your spacecraft has done a pretty impressive job of coming up with stars that have not been seen before.

Well, that's true. So we actually set out with a special goal of seeing brown dwarf stars, which are objects that are not massive enough to fuse hydrogen to helium. And as a result, they gradually cool off. And while they start off when they're young, emitting visible light, after a billion years, they're only radiating infrared light. So WISE has a good chance to see a lot of these nearby brown dwarf stars. And these are perhaps the most numerous things in the solar neighborhood. Well, what is WISE telling us about the quantity of these small and reasonably dark objects? Well, we don't really have the analysis done to say exactly what the population density is.

What's really required, once we have found some brown dwarfs, and from the colors you can say that it definitely looks like a brown dwarf star, in particular methane, which is strong in the atmosphere of Jupiter, is also strong in the atmosphere of brown dwarf stars. And so when you see methane in the atmosphere, you're pretty confident that you have a brown dwarf star. But what we don't know right away is how far away the object is. So it's necessary to follow it for a few years to see it move across the sky and to see it wiggle back and forth due to the motion of the Earth around the sun. I don't know what else you'd like to say about the data that WISE has returned, but I do want to mention that on your website, which we will link to where people

can find this show at planetary.org, you also have some very beautiful images, which is not something I necessarily expected to get from WISE. Well, the important thing to realize is that the wavelength doesn't determine whether you can make a beautiful image. It's really important to look at a large area on the sky and then be able to make these mosaics that WISE is making. So from the fact that we're looking at the whole sky, you know, we really have a lot of targets from which to choose in order to make these beautiful images. Can you say something about a couple of images that are on the site? One is of the Pleiades' invisible light, the way we know them from the surface of this planet, but then this really stunning one that shows there's much going on,

much more going on out there in the region of those stars. Well, that's right. The interesting thing with the Pleiades is that these stars, it's a fairly young star cluster, have actually just bumped into an interstellar cloud of dust. So they're moving along and they've just run into a cloud of dust. It's not the dust out of which the stars formed originally. And as a result, even in the visible, you can see reflected light. The dust grains reflect light from the bright, hot stars. But in the infrared, of course, these dust grains also absorb light,

heat up, and then radiate a lot of infrared. That's Ned Wright, principal investigator for the WISE mission. He'll be back with more after a break. This is Planetary Radio. I'm Robert Picardo. I traveled across the galaxy as the doctor in Star Trek Voyager. Then I joined the Planetary Society to become part of the real adventure of space exploration. The Society fights for missions that unveil the secrets of the solar system. It searches for other intelligences in the universe, and it built the

first solar sail. It also shares the wonder through this radio show, its website, and other exciting projects that reach around the globe. I'm proud to be part of this greatest of all voyages, and I hope you'll consider joining us. You can learn more about the Planetary Society at our website, planetary.org slash radio, or by calling 1-800-9-WORLDS.

Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt. Our nearly 100,000 members receive the internationally acclaimed Planetary Report magazine. That's planetary.org slash radio. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. WISE is the Wide Field Infrared Survey Explorer. Almost exactly seven months after its December launch, the Wide Angle Telescope completed its first survey of the sky,

unveiling everything from cool brown dwarf stars to even cooler near-Earth objects. UCLA professor Ned Wright serves as the mission's principal investigator. When will your data make it out to the rest of the scientific community? Well, certain parts of the data are going out immediately, and that's the asteroid positions, because a stale asteroid position just means you have a lost asteroid. But the main data releases are scheduled for six months after the last data is taken, and then 11 months later than that. So that means, based on how long we think that the hydrogen coolant in the cryostat will last, it's going

to be about May 2011 that the first half of the data will come out. That's the preliminary data release. You mentioned the hydrogen coolant, which is a key factor in the success of this spacecraft. Could you talk a little bit about how WISE does the job that it's doing? Well, WISE has to be a cold telescope, because a room temperature telescope would just radiate a lot of infrared. And if you are trying to observe faint stars with a telescope made out of light bulbs, it just doesn't work. So you need to have the telescope cold so it doesn't radiate and blind itself. And then you also need to have the detectors cold, because the detectors are perfectly capable of detecting anything at room temperature, even themselves. And so the detectors need to be quite cold.

In fact, we're running the detectors at about 8 degrees Kelvin for the long wavelength channels. That's 8 degrees on the centigrade scale above absolute zero. And that's where they need to be to operate. The telescope is not quite that cold, but it's really quite cold. So it doesn't radiate anything in the infrared in our passband. What happens to WISE when you run out of that hydrogen coolant? Well, WISE will basically continue orbiting around the Earth, but won't be observing at long wavelengths. It could, in principle, though we're not certain, observe in its short wavelength bands.

These are the ones that actually aren't all that useful for finding asteroids, but still could be useful for some other projects. But the funding will run out, and so we will basically turn off the spacecraft. It will continue to orbit around the Earth until atmospheric drag causes it to reenter. Still so much to do in this mission before you do run out of that hydrogen. What is WISE up to now? Has it begun another survey of the sky? That's right. After finishing the first survey of the sky, we just started another one. And so we just continue surveying. We basically observe a circle that's perpendicular to the Earth's sun line.

And so we're just continuing to do that. And this is very important for getting multiple observations of objects on the sky. But it's also very important for asteroids, which move. of objects on the sky, but it's also very important for asteroids which move. And so while we've seen the entire sky, we haven't seen all the asteroids in the solar system. Many of them have managed to move in such a way that WISE has never looked at them. How many images has WISE actually captured and sent back down to us so far? Well, it is nearly 1.4 million images. We take about 7,000 per day.

Now, when I say an image, I'm talking about four images because we have four colors that we take simultaneously of the same field. So it is really a large amount of data, about 5 trillion pixels so far. Wow. And it's all transmitted down to the ground. How does WISE fit into this panoply of space-based instruments, and for that matter, ground-based instruments? I think in particular of Spitzer, another infrared instrument, but one with a very different job.

Well, Spitzer is a pointed observatory, and so it's not really capable of surveying a large area of the sky. But when it does point at an object, it's more sensitive than wise. You can also do infrared observations with Hubble Space Telescope. And in the future, we'll be able to do very sensitive infrared observations with the James Webb Space Telescope. Now, all of these are narrow field of view pointed observatories. So you need to find objects that are interesting for them to study. And the purpose of WISE is to be the wide angle panoramic survey instrument that finds the most interesting objects for these big telescopes, which act like telephoto lenses, to zero in on.

That implies that WISE is going to leave quite a legacy when it ends its life up there in orbit. It certainly will. We expect that the WISE catalog and image atlas will be used for decades to come as a resource to study the universe and this important infrared wavelength. Ned, I want to thank you again for rejoining us on Planetary Radio, and I hope that maybe with the completion of that second sky survey, if not for the release of additional data, all of that stuff other than the asteroid data. Maybe we can get you back on the show.

Okay. Thank you very much, Matt. Edward L. Wright, or Ned Wright, holds the David Saxon Presidential Chair in Physics. He's a professor of physics and astronomy at the University of California, Los Angeles. And, of course, we've been talking to him in his capacity as the principal investigator for the WISE mission, WISE, the Wide Field Infrared Survey Explorer. We'll do some much simpler, much easier exploration of the night sky with Bruce Betts when we come back in just a few moments. Bruce Fetz is here. He's the director of projects for the Planetary Society. He joins us every week for What's Up,

this time with a brand-new snowball microphone. And listeners, drop us a line, send email, because I think he sounds much much better but you tell us what you think here he is now how do I sound? like the godfather make you an offer you can't refuse

now tell us about a sky we can't avoid alright when you go and look at the night sky you need to go to the mattresses and when you do you're going to see a whole cluster of planets over in the west after sunset. They're dancing around. It's hard to even keep you updated on their relative movements. In the west, we've got Saturn, Mars, Venus, Regulus, and if you can see low enough, Mercury. Close to the horizon, find Venus first, the really bright star-like object.

And then look to its upper left. You'll see Saturn and Mars, and they are going to come together and snuggle around July 30th, be very close in the sky. Mars, of course, the more reddish of the two. And then to Venus's lower right, if you've got a clear look at the horizon, you'll see Mercury looking fairly bright and very similar looking to it. Regulus, the brightest star of Leo. And the two of them have a snuggle fest even earlier on July 27th, so pretty much right away. You can still check out Jupiter rising late in the evening and up in the pre-dawn, high overhead, looking bright and very star-like.

Let us go on to this week in space history. Apollo 15 launched and landed during this week in 1971. You know what that means, Matt? No. First driving around on a lunar surface. Oh yeah, the jalopy. Okay. Well, they called it the lunar rover, but yeah, pretty much. And also this week, a couple of years later, in 1973, the Skylab 3 crew launched on its 59-day mission to Skylab. They did not set the record for the longest time for people to be continuously manning things in orbit, but we'll talk about that in just a little bit. First, we'll go on to this week's Random Space Fact.

In hi-fi. Space Fact in Hi-Fi. Did you know, Matt, there have been six successful robotic sample return missions from beyond low Earth orbit? Really? Three. Of course, three from the Moon. We covered that last week. Exactly.

The three lunas. And they returned two of them to Kazakhstan, one of them to Siberia. And then we had Stardust and Genesis coming back to Utah carrying, respectively, parts of them to Siberia. And then we had Stardust and Genesis coming back to Utah, carrying respectively parts of a comet and parts of the solar wind. And then most recently, Hayabusa returning, landing in Australia. We're still waiting to find out exactly how much, what sample they got, but they got back here. Good. Let's see lots more of these sample return missions. Okay. I'll get to work on that.

Meanwhile, let's talk about trivia. How long was the longest period of continuous human presence in space? That's what we asked you. And what dates did it span? How'd we do, Matt? It's summer, so things do fall off a little bit, although we've got a big response coming up for next week because a lot of people want that Celestron weather station. So the odds were pretty good this week, and they smiled upon Chris Midden. Chris Midden of

Carbondale, Illinois, I believe a first-time winner. Congratulations, Chris. Here's what he said. It started with the Soviet Union's launch of Soyuz TM-8 on the 5th of September 1989 and ran to the landing of Soyuz TM-29 almost 10 years, just eight days short of 10 years on the 28th of August 1999, 3,644 days. They did some good stuff back in those days, those Soviet folks. It was one of those interesting things. It started as Soviet and it ended as Russian. Oh, that's right, of course. And that, of course, in the core there was Mir. They were delivering people to Mir, but we count from the first launch to Mir to the last return of humans from the Mir space station. And also, it's interesting, Matt, is on October 23rd of this year,

the International Space Station continuous human presence will eclipse that number and move us past 10 years shortly thereafter. Good reason to celebrate up there on the ISS. I got one more I got to tell you about, William Stewart. You know, we still get tons of wonderful responses that go above and beyond the call from our listeners. This one from William Stewart, who wondered over those 10 years how far behind the clock on Mir would have gotten due to relativistic effects. Eleven hundredths of a second was lost over those 10 years, according to Williams' relativistic calculations. That's a really non-trivial amount.

That is. Yeah, right. It's a tiny amount compared to my clock, but that's just because I'm always traveling near the speed of light. Let us go on to the next contest. And it's just a space station kind of day here. So I'm going to ask you, and if you can just picture the space station, you can answer this. How many solar arrays are mounted on the external truss of the ISS to provide power? Solar arrays mounted on the external truss.

Go to planetary.org slash radio. Find out how to enter. You know, I can picture it pretty well, but counting them, people, you won't find any trouble, won't have any trouble finding a shot of this, right? Count them up. And send us that number by 2 p.m. on Monday, August 2nd. That's 2 p.m.

Pacific time on Monday, August 2nd, and you'll be in the contest. Might win yourself a Planetary Radio t-shirt. Okay, everybody, go out there, look up at the night sky, and think about dust and what it might be made of. Thank you, and good night. You don't really want to know.

That's what I learned about it. He's Bruce Betts, the Director of Projects for the Planetary Society. We'll get into another Dust-Up with him next week in our next edition of What's Up. Psst! You're invited. The Planetary Society. We'll get into another dust-up with him next week in our next edition of What's Up. sign a birthday card for Ray Bradbury, and enjoy some ice cream. Go to planetary.org slash radio and click this week's show to get the link. You won't find it on the homepage. Planetary Radio is made possible in part by a grant from the Kenneth T. and Eileen L. Norris Foundation. Keep looking up. Редактор субтитров А.Семкин Корректор А.Егорова