Planetary Radio: Space Exploration, Astronomy and Science - Dark Energy’s Co-Discoverer and the Leader of Chinese Space Science

Episode Date: August 8, 2018

It has been 20 years since we learned the expansion of the universe is accelerating due to the mysterious force called dark energy. Saul Perlmutter shared the Nobel Prize in Physics because of his contributions. Now he shares his thoughts with us.  Also at this year’s COSPAR Assembly in Pasadena was the Director General of China’s National Space Science Center, Wang Chi.  Have you played with Eyes on the Solar System?  JPL’s Kevin Hussey conceived of the NASA Eyes app that will take you across the solar system and beyond.  And you’ll hear Planetary Society co-founder Carl Sagan’s message to the Martians in our future.  That’s right after this week’s What’s Up.  Learn more at:   http://www.planetary.org/multimedia/planetary-radio/show/2018/0808-2018-saul-permutter-wang-chi-nssc.htmlLearn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

No big deal, just a Nobel Prize winner and the leader of space science in China, this week on Planetary Radio. Welcome, I'm Matt Kaplan of the Planetary Society with more of the human adventure across our solar system and beyond. Does dark energy delight or disgust you? Either way, the first person to thank or blame is Saul Perlmutter. The Nobel Committee gave him half of the credit for its discovery. We'll talk with Saul along with Wang Qi, Director General of China's National Space Science Center. Then, just for fun, we'll talk with Kevin Hussey, creator of NASA Eyes. The growing collection of apps that will take you along with Cassini and

Voyager are out to world circling other stars. Stay through this week's What's Up with Bruce Betts for a lovely message that Carl Sagan created for future Martians. It was 20 years ago today, more or less, that we first heard the expansion of our universe is accelerating. Two decades later, we still don't know why, but we do know it was predicted by Einstein's general theory of relativity and then rejected by Albert himself as being too, too crazy. When the Nobel Prize for this discovery was awarded in 2011, half of the credit went to Saul Perlmutter of UC Berkeley. Saul is a physicist, of course, but as you'll hear, he is an experimentalist, examining the real, observable

world to prove or disprove explanations theorists come up with, and sometimes to reveal corners of existence that catch those theorists by surprise. The recent biannual meeting of the International Committee on Space Research devoted an entire track to this 20th anniversary and to a review of what we know and don't know about dark energy. Not surprisingly, Professor Perlmutter was the lead speaker. Dr. Perlmutter just came out of the presentation that you gave to open the COSPAR sessions on dark energy. You seem to be having a delightful time talking about how you helped to get us, led the effort to get us to where we are now, which is, I think I described to you a moment ago, is turning the world of astrophysics on its head. I do feel it was such a lucky period to walk into a project where it was possible to ask something you really

cared about to be able to see a whole technique develop and have the experience of all the difficulties tying you down for years but one by one working through them and getting to the point where you actually got a result that not only would have been fun whatever the answer was but turned out to be a surprise. So that was actually my next question. How great a surprise was this that you found something that even Einstein thought, oh, that's silly, and he threw it out? What's funny is that at the time, your main concern as you're trying to do these projects is this can't be right. We must have done something wrong. And so you spend, oh, we spent a good fraction of a year, probably six to nine months, just trying to track down

every possible thing that could have gone wrong that may have given this result. And then finally, by the time you believed it, you had been staring at it for a year. So it wasn't like the surprise felt like a surprise in itself. It was just that you actually had to face the fact that the world was different than we thought. Well, it certainly came as a surprise, rather a shock, I think, to much of the world of astrophysics. I think it was most obvious once we actually started going out and giving the first talks about it. So by then we had gotten used to seeing it,

but once you actually started presenting it to other physicists and astrophysicists, and they said, I remember in one of the very first talks I gave, a very prominent cosmologist, Joel Premack, stood up and he turned to the audience of physicists and said, you guys may not realize this, but this is a shocking result. And it forced me, of course, to stop and think, that's right, I've been worried about how to present it, but it actually really is shocking. You mean you needed to step back from it? Exactly, exactly.

And I think just when you come back to the group, when you come back to the community, and then you digest it together, that's when you really start realizing what it is that you're seeing. Have you also thought about what I just referred to, that Einstein threw this out, and how he basically, you have vindicated him as he has been vindicated over and over, over the last hundred plus years. I mean, it's just amazing how, for some magical reason, the world seems to be amenable to being studied with mathematics,

so that when you come up with a really strong mathematical theory, you can actually predict things that you don't even believe, as Einstein didn't. So I've been kidding with my friends that Einstein could have stuck to his guns and predicted that the universe was expanding, and he threw in the cosmological constant and made it to try to make a way,

and he could have been famous. That's great. Do you have a lot of theorists as friends? Well, the great thing about, I think, the style of how physics has built up over the last 50, 75 years or maybe even a century now is that physicists are this great combination of theorists and experimentalists

who are constantly giving each other a hard time. Because from the point of view of the experimentalists, the theorists will come up with 50 theories before they go to sleep at night, and any one of them could be right or could be wrong, whereas from the point of view of the theorists, the experimentalists haven't done anything in the past 10 years because they've been working on one particular measurement. But the mix is really important, obviously,

because it means that it's very hard to understand what you should be looking at as an experimentalist unless there's some theoretical constructs that you're trying to work with and understand. And similarly, from the point of view of the theorists, of course, you can't make any progress unless you touch base with reality that you're getting from the experiments and the observations. So it is a mutually beneficial, actually essential

relationship. And we should say, if it's not clear to everyone, you are definitely in the camp of the experimentalists, which is perhaps why you're having so much fun with this. That's right. And I think that this is one of those cases where the surprising result has actually led the theorists to try out all sorts of interesting new ideas. But I think the story hasn't settled yet. And I don't think it will settle until we have some other experimental framework and some other observations to help pin down which directions the theory is going to go. to help pin down which directions the theory is going to go. Before we talk about where that is going, because you talked a little bit about this newer,

even newer era that we're headed into, you gave a pretty wonderful example of how theorists have gone wild with this, that you think that there's been roughly a new theory every what? Well, there's been a paper published. It looks like it's roughly every 24 hours there's a published paper. Now, of course, not everyone really represents a completely different theory. But it's also true that the number of theories has been extraordinary, the number of theoretical ideas that people are trying out.

It's very fertile as a way to think with. Have we reached the point where at least some of these theoretical approaches have been eliminated or at least downgraded? Very few are out of the question at the moment because, as I was saying in the talk just now, the kinds of differences they make in the history of the expansion of the universe and in the growth of structure in the universe are very subtle. And you need this next generation of experiments that we're about to get to differentiate most of these theories. There are a few that I think we now know can't be true,

but I'd say most are in play. And you talked about this next stage and some of the instruments coming online, LSST, Euclid, WFIRST, which of course we still hope will happen sometime in the 2020s, right? How much closer do you expect, or can we even say how much closer this will take us to understanding what's really going on? In one sense, we can't guess, because since we don't have a very strong choice among the theories right now. There's no strong indication of exactly what measurement will be the one that makes all the difference. On the other hand, it feels like we still live in a fairly young period of this field of cosmology where we have not made big advances in measurements

without having big advances in surprises and results. Since these next-generation experiments are going to make really big advances in surprises and results. Since these next-generation experiments are going to make really big advances in the measurements, I'm expecting we'll see some big surprises and we'll get some interesting new results. This is shot in the dark, if you'll pardon the pun. But with the even more recent proof of the existence of gravity waves

and now the beginnings of gravity-based astronomy. Do you think that there may be a tie between these? Towards the end of my talk, I was asked whether or not we might be able to find other measurement tools besides supernova to make distance measurements in that particular technique using what they call standard candles. And one of the more exciting possibilities is that we might be able to use gravitational waves. People have been figuring out ways to take just these signals that we get from across the universe and treat them as if they were a light bulb that somebody's walking across the universe with. And if we can figure out how to do that, they could be very important. The Nobel Committee decided that you deserved what I'll call the lion's share of the credit for this discovery. But I know that there were many, many other scientists working around the world that led to this.

And you talked about some of that, the work that was underway all over the world that contributed the data that led to this decision. And I want to see if you have anything to say about that team and what it takes to make this kind of discovery. These prizes are really just symbolic recognitions of an effort that are absolutely team efforts. For the project I was doing, when we went to Stockholm, we went with 32 team members and their families and it was a team celebration and similarly the team that we shared it with they all came as well and we all had a joint event

together in fact at the time but it takes so many different skills and capabilities to do almost any really interesting significant project that I think of it as almost the opposite of what I think people's imagination of what science is. They picture the lone scientist in the lab coat by themselves. My experience is the exact opposite, that it's one of the most social activities you can do and that if you are going to be doing these kinds of experiments really, really well, you're going to be working with groups of people that are exciting to work with. And that's the, it's the pleasures, it's the difficulties.

I mean, all of the activities are social activities when it comes to this kind of science. And I'm keeping you from one of the most productive social activities that is available today, and that is the continuing presentations in the room that we're standing right outside of. I will let you go back to that. But thank you so much. And 20 years late, congratulations on this fantastic discovery. It's a pleasure to talk.

Saul Perlmutter, who shared the 2011 Nobel Prize for the discovery of dark energy. After talking with Saul, I strolled across the Pasadena Convention Center and into the Coast Bar Exhibit Hall. I couldn't help noticing a large central exhibit belonging to the National Space Science Center in China. The NSSC was established in 1958, the same year NASA came into being. It describes itself as China's gateway to space science, the key institute responsible for planning, developing, launching, and operating

China's space science satellite missions. It also spearheads space science research in the fields of space physics and environment, microwave remote sensing, and space engineering. Working as part of the Chinese Academy of Sciences, the center was responsible for that nation's first satellite launched back in 1970. It has a staff of 700 that includes more than 300 scientists. I was introduced to the center's director general, Wang Qi. He has led the agency since late last year. It is a great honor to speak to you as the head of the agency in China and to welcome you to

the Coast Park Conference. I hope it is going well for your team who are here with this exhibit so far. Yes, actually, this is our first time to exhibit in the COSPAR meeting. We are the newcomer in the space science stage. During the last five years, we launched four space science satellites, and also within the next five years, we launched four space science satellites, and also within the next five years, we are going to launch four space science missions. So this is a golden age for space science.

Around the world, but it certainly seems like the dawning of a golden age in China. I just read only days ago about these four new missions that have just been announced. Yes, that's including the Einstein probe. It's a time domain astronomy and we are going to conduct a soft X-ray monitor of the Earth sky to study the transitions to black horse and

something like that basically is a X-ray astronomy observatory and the second one we are going to study our nearby star this is the sun you know the sun has sometimes it has eruptions we call the solar blast or solar eruptions solar flare sometimes yeah and this including two type of storms one is solar flares the other one is the chloral mass ejections so we try to understand what the relationship between the solar flares and the clonal mass ejections and their relationship to the solar magnetic field. So this is the second mission. The third one we call the SMILE mission.

That is called the Solar Worm Magnetosphere and Outer Sphere Field Link Explorer. and that is called the SolarWinds Magnetosphere and EarthSphereLink Explorer that will take the picture of the magnetosphere. As you know, even though we have already studied for the magnetosphere for more than 70 years, we have never made a global picture of the magnetosphere. So this will be our first time to have these opportunities. And this is a joint space science mission between European Space Agency and China. We are looking forward to that.

And the first one we call the JICA. As you know, the American NIGO program, they have been successful in detecting the gravitational waves on the ground. By 2020, they will upgrade. And they will have high sensitivities to observe the gravitational waves on the ground. So in the meantime, we will launch the GECOM satellite. The main purpose, so we try to find the electromagnetic counterpart of the gravitational waves. So that means, where is the source of gravitational waves? Does the source emit the electromagnetic signals?

We don't know. So we try to understand their relationship. So these are our four space satellites that will be launched within the next five years. I am also thinking of the plans that China has, the successes that China has already had on the Moon, our nearest neighbor in space, and the mission that is already coming together. You already have the communications satellite, right, that is ready to beam back science and images from the far side of the Moon. Please talk about that.

Yes. And in China, we have a different agency to take charge of the lunar and deep space exploration. Our center is responsible for the science and application of this deep space program. This year we will launch a town of four, we will go to the far side of the moon. We will do the soft landing. I think this is the first time for human being to soft land on the far side of the moon. And in the middle of this year,

we already successfully launched a relay satellite that will make the communication between Earth and the lander. So this is the time of four mission. Next year we are going to have December return mission from the moon. That will be probably by the end of next year. So China will finish the three steps. The first step is the orbiting of the moon. The second step is landing. And the third step is simple return from the moon.

And in 2020, we are going to launch the first Chinese Mars mission. We call it Mars One. We will send both the Mars orbiter and the lander and the rover all together in one mission. This is such an impressive and ambitious program. I mean, China may be a newcomer to space science, but you seem to be making up what we would say is making up for lost time. Why do you think China is now almost suddenly so motivated to become a major player in space science and planetary science research, research across the universe? I think first of all, because the Chinese economy has boomed in recent years, so we

have enough resources to conduct the space science and the planetary science. On the other hand, as the largest population of the earth, I think the Chinese should and will make a contribution to the human being. I think also of China's long history. There was a pause in that history, but hundreds of years ago when China was a leader in science. I'm not totally agree with you because I think China is a leader in technology, not in science. I see.

But you see a time, actually it seems like that time is here, when the science may get, if not equal, it certainly is getting much more attention as compared to the leadership in technology. Exactly. So when you're looking through the modern textbook, this is low Chinese names in it.

So we try to make more contribution to the knowledge of human being. So this is our purpose. You addressed for a moment some of the international collaborations that China is participating in. Is that something that China hopes to continue? All the Chinese space science program, we are open to international collaboration. We do think space science is not something for

one country, it is for all the globe, for all the people on earth. So that is why Chinese program, space program, are open to international collaboration. For example, during the next five years, we have a mission called Smile. This is a joint mission between ESA and China, and also in China 4. We have some payload from Europe. It is a very exciting time, and I think also is represented by the fact that you are here with this large booth at at Coast Bar in Pasadena. Exactly. In the future we are looking forward to the U.S. payload on board the Chinese satellite or Westwise. And many of us would love to see that happen because

we can learn together. Exactly. Thank you very much for taking a few minutes and I hope that this is a very successful stay for you at the Coast Park Conference. Thank you very much. Wang Qi, Director General of the National Space Science Center in China, part of the Chinese Academy of Sciences. Not far away was an even larger exhibit belonging to NASA. In one of its corners was a big screen running an app I immediately recognized. The app was Eyes on the Solar System, part of a growing family of NASA Eyes apps. Kevin Hussey manages the Jet Propulsion Lab's Visualization Technology Applications and Development Communications and Education Directorate. Hearing that light-years-long title might distract you from the fact that he is the

primary conceiver and creator of NASA Eyes, and that he takes enormous delight in sharing his babies. You had a very large role in creating one of our favorite apps at the Planetary Society, Eyes on the Solar System, although it's much more than that now. Yes, it's Eyes on the Solar System, Eyes on the Earth, and Eyes on Exoplanets. Eyes on the Earth was actually done first, and then we moved on to the solar system

after having a success on the Earth. Let's talk about Eyes on the Solar System, because there is so much that you can do with this program. Eyes on the Solar System, I like to describe it as a virtual reality viewer for the entire solar system from 1950 through 2050. We have the robotic missions, almost all of them are included, so that you can virtually ride along with majority of the robotic missions. For example, you can ride along with Voyager as it flew past Saturn for the first time

and be able to witness what it would have looked like if you were virtually flying alongside. This is the purpose of Eyes on the Solar System. Let individuals virtually explore along with your robotic spacecraft. You have complete control over the time scale as well, so that you could do the whole Voyager Grand Tour in whatever amount of time you want. Whatever you want.

In fact, we have the Cassini mission. We made what's called a special feature for Cassini. From the time the second stage ended, you can follow the Cassini mission in real time all the way through until it vaporizes in the atmosphere. Although we were not allowed to show the vaporization because it was too emotional for a lot of the people on lab. So we just disappear at the time it disappears. But you can watch the entire mission. And by the way, every move that it makes, its attitude,

and you can watch how the cameras are pointed for the entire mission. Every flyby of the moons, it's all loaded into eyes. So what about on the surface of Mars? All we can do for the surface is basically show you the landing site for Curiosity. We are working on a new version that will allow you to travel along with the rover, but that's coming in the future. Eyes, again, written about seven or eight years ago. We are using the Unity 3D game engine. It was built a long time ago, so we have stretched it as far as it can go. We are now in the process of rewriting it in WebGL, so you can use it from your browser. Is Eyes on Exoplanets the latest edition that's actually available?

Eyes on Exoplanets is the latest of the Eyes series, and it visualizes the NEXAI, which is the NASA Exoplanet Science Database, that's housed down at Caltech. And every night after midnight, we go down and we look at the database, and we determine if there have been any more planets around distant stars that have been confirmed. If they've been confirmed, we automatically load them into isonexoplanets so you can virtually fly to that system and observe it. Or at least what we imagine it could look like.

Yeah, the actual configuration of the solar system is correct, the distance from the planets that we can surmise. But the visual itself is just a... Artist concept? I think that's a fair way to put it. Because we do not know what they look like. Not yet, anyway. Isn't it incredible?

I mean, you may be old enough, I know I am, to remember being told, oh, we may never be able to detect or much less see a planet circling another star. It is so exciting. I mean, we've gone from 20 years ago when we found the first confirmed exoplanet to now there are about 3,500 confirmed in this database.

And scientists believe that when you look up in the night sky and you see a star, the odds are way higher that there are multiple planets there than none. It's a great time to be alive. What were you doing? You had a little augmented reality Curiosity rover, or was that the 2020 rover, sitting here on the table I'm leaning on? It was a Curiosity rover, and it was sitting on the table virtually, and it's an app called Spacecraft 3D, which is available either at Google Play if you're on Android, which is available either at Google Play if you're on Android or in the iTunes or the App Store if you're on iOS.

You can download it, and it allows you to take 27 of the models that are in eyes and place them wherever you want in your environment and visualize them in 3D in augmented reality. And I saw you raising the mast and extending the boom, and you had your own little rover sitting on the table. Yes, several of them that have animatable parts. We've done little animations, and you're allowed to control those animations as well as you could take the marker, and I've done this repeatedly,

and I'll put it on somebody's shoulder, and then I'll take a picture. And those pictures are kind of fun because I'm going to show you one right here this is where of course it hurts that we are on radio but I want you to notice it's kind of funny about this this one here shows a gentleman it appears that curiosity is giving him a either cleaning his teeth or drilling out a cavity maybe someday that would be a great spin-off to have a rover sitting on your shoulder a little personal assistant okay fantastically powerful apps great spinoff to have a rover sitting on your shoulder, a little personal assistant. Okay, fantastically powerful apps, great fun. You must be charging a fortune to get to download these.

Yes, this costs you just paying your taxes. I like to put it this way. It's no additional cost to the U.S. taxpayer. And if you're lucky enough to be one of the third or so of the people who listen to this program outside the U.S. It's a freebie. Once again, how can people get everything? You talked about the augmented reality, but how about the Eyes On series? Eyes on the solar system, Eyes on the Earth, and Eyes on Exoplanets are available at eyes.nasa.gov.

Just eyes like your eyeballs,.nasa.gov. You go there, pretty much anything that we've talked about is downloadable, except for the augmented reality app because you go directly to the Google Play or the iOS store. But all the ICE programs are available at eyes.nasa.gov. Great work, Kevin. I'm a big fan, and I highly recommend anybody who hasn't seen these ought to take a look. Thanks a lot. You're welcome. It was my pleasure. JPL's Kevin Hussey at the Coast Bar meeting in Pasadena, California. It's time for What's Up on Planetary Radio. Bruce Betts is the chief scientist, the leader of all science at the Planetary Society.

And the world! He's here. He's with us in this session, ready to bring us the night sky, which is still quite beautiful. Mars was just gorgeous again last night. I did get the telescope out a couple of days ago. The sky was just clear enough, just long enough for me to get a good look at a very cloudy Mars. Good. Did you happen to point it over to Saturn or Jupiter? You know, I got Jupiter, and because my finder scope is broken for some reason, the little laser spot thing, I didn't even want to try for Saturn

because it's just such a drag to try and align that thing when the finder's not working. And I'm basically just equal parts bad amateur and lazy. Use the force. Feel the presence of Saturn. Reach out. But you make it real for me, so I don't need to do that stuff. Well, let's get real. So yeah, that's what's up and will be for the next few weeks.

But Mars will keep dimming. So see it soon, see it often. Mars in the east, southeast after sunset, can't miss it. Still stupid bright to use the technical term. It is reddish, orangish. And then as you rotate yourself across the southern sky, at least for we northern hemispheres, then you will see Saturn that Matt will ignore. But you shouldn't. Yellow Saturn. And then bright Jupiter. And then all the way over in the west, super bright Venus, which is getting lower.

But you still can't miss it if you look fairly soon after sunset. So try a half hour to an hour after sunset and check out the four planets. Also, if you're picking this up early enough, you can still catch the Perseid meteor shower peak the night of August 12th and 13th, but there'll be increased activity several days before and after. It's a broad peak. Moonlight, not an issue this year because it will be new moons, so a particularly good night to check out the Perseids. Or nights.

I'm looking forward to that. And I hear tell that the storm, the planet-wide storm on Mars is waning, so might be able to see a little bit more detail now? Yeah, if you've got the telescope to do it. But yeah, the global dust storm is waning, and so dark features are starting to appear again in addition to the polar cap. Let's hope Opportunity reappears again as well. We move on to this week in space history.

It was 1990 that the NASA Magellan spacecraft entered Venus orbit, giving us a whole new higher-resolution radar map of the surface through the thick clouds. And then 2005, Mars Reconnaissance Orbiter was launched, and it's still doing great stuff at Mars. Yeah. We move on to... Space, space, space, space.

Back, back, back, back, back, back. You know, I can provide echo for you. You don't have to fake it. Darn it. I forget sometimes. We'll just do echo on top of echo for this. In fact, we just did. Recursive echo.

Perseid meteor shower going on right now. The source of the Perseid meteor shower is comet Swift-Tuttle, periodic comet with a current orbital period of around 133 years. So in cometary terms, comes back around fairly often, but maybe not in people terms. Yeah, I guess not. But it's debris, the crud that it's kicked out and now orbits in that orbit, Earth runs into every year. And we call it the Perseids.

What a slob. It's sloppiness is our prettiness. We don't have an old trivia contest answer for you. Is that right, Matt? Is that how it works? You are correct, Chief Scientist, because remember, we decided we would give people who never are able to meet the deadline that we set one week out from when we offer the new question, the new contest. We thought, okay, we'll give you two weeks. So the contest of two weeks ago, we just hit the deadline for that. Turns out the turnout beyond the normal deadline has been, shall we say, minuscule, infinitesimal.

So we won't continue that experiment. We can go directly. And it means we'll have two contests to provide the answers for next time. Oh, joy. That'll be fun. And we can go straight on toward morning. We can go straight on toward whatever you've got for next time. What were the names of the stars in Peter Pan that they go past?

Never mind. It's not the real question. The real question is much more scientific. What singer-songwriter referred to an experience watching the Perseid meteor shower as, I've seen it raining fire in the sky? Go to planetary.org slash radio contest. I know. I was once a really bad DJ as well as a terrible amateur astronomer. You have this time until the 16th, August 16th at 8 a.m. Pacific time to get us the answer.

And we have a Planetary Radio t-shirt waiting for the winner of this, along with a 200-point itelescope.net account. itelescope, worldwide nonprofit network of telescopes that anybody can make use of, anybody who's got a system to go online, a device. And, of course, ShopShop is where those T-shirts come from. You can find the Planetary Society store there at chopshopstore.com. But wait, there's more. Yay! Have you seen Distant Suns? It was one of the first great astronomy apps created by Mike Smithwick,

who is still working on his own. He's been doing this for over 30 years and he has a new version out. Now I'll warn people it's only for iOS. It's only for Apple devices, but the new version is called Distant Suns VR, as in, say it with me, virtual reality, because you can use Google Cardboard or some similar device and actually place yourself among the stars. It's pretty cool. And we have, this is not worth a whole lot because he doesn't charge a lot for the app, but we will give you a code that will, if you have an Apple device, get you this Distant Suns VR brand new release for free. And it's great fun. I played with it's great fun.

I played with it a little bit. I haven't done the VR yet. Got to find my Google Cardboard viewer, but it's really fun. Remember to use both eyes this time. Arr, matey. If only I could. Aw.

Wait, wait. Well, I'm glad you got to use that. Thank you. I'll get the timing a little better next time. I think we're done. All right, everybody, go out there, look up the night sky, and think about if a housefly lands in butter and then takes off again, does it become a butterfly?

Thank you, and good night. You're really having fun with these, aren't you? Wouldn't happen in our house. It would have to be, and I can't believe it's not butterfly. Someone owes us money. I don't know who. Find out who. I'll get our huge staff to find out who makes that product.

Bruce Betts is the chief scientist for the Planetary Society, but you knew that. And he joins me every week here for What's Up. Back in 1996, not long before he passed away, Planetary Society co-founder Carl Sagan recorded a special message. In 2008, that message finally made it to Mars on a DVD the Planetary Society created for the Phoenix Lander. In honor of Mars' close pass by Earth that is still underway in this summer of 2018, the Society's Merck Boyan has produced a beautiful video that uses Carl's message as its narration. We've got a link to that video on this week's show page, reached from planetary.org slash radio.

Here is that message from Dr. Sagan. Hi, I'm Carl Sagan. This is a place where I often work in Ithaca, New York, near Cornell University. Maybe you can hear in the background a 200-foot waterfall, which is probably, I would guess, a rarity on Mars. I don't know why you're on Mars. I don't know why you're on Mars. Maybe you're there because we've recognized we have to carefully move small asteroids around to avert the possibility of one impacting the Earth with catastrophic consequences. And while we're up in near-Earth space, it's only a hop, skip and a jump to Mars.

Maybe we're on Mars because we recognize that if there are human communities in many worlds, the chances of us being rendered extinct by some catastrophe on one world is much less. Or maybe we're on Mars because we have to be, because there is a deep nomadic impulse built into us by the evolutionary process. We come, after all, from hunter-gatherers and from 99.9% of our tenure on Earth. We've been wanderers, and the next place to wander to is Mars. But whatever the reason you're on Mars is, I'm glad you're there, and I wish I was with you. Planetary Radio is produced by the Planetary Society in Pasadena, California,

and is made possible by its bright and energetic members. Mary Liz Bender is our associate producer. Josh Doyle composed our theme, which was arranged and performed by Peter Schlosser. I'm Matt Kaplan. Ad Astra.