Planetary Radio: Space Exploration, Astronomy and Science - Something Old and Something New: Exciting Research on the International Space Station

Episode Date: July 11, 2018

Sextants have helped sailors find their way across oceans for centuries. Now one is onboard the International Space Station so that astronauts can learn to find their way across the solar system even if other technologies fail. Reaching the ISS on the same supply mission was the Cold Atom Lab.  It may achieve the lowest temperatures in the universe, helping to unlock cosmic secrets.  Every naked eye planet is visible!  Bruce Betts will tell you where to look in What’s Up.  Learn more about all our topics and hear extended interviews:   http://www.planetary.org/multimedia/planetary-radio/show/2018/0711-2018-sextant-and-cold-atom-lab-on-iss.htmlLearn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Something very old and something cutting-edge new, 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. The sextant. It has been helping sailors find their way across treacherous seas for centuries. sailors find their way across treacherous seas for centuries. A sextant that those ancient mariners would recognize has just gone to the International Space Station. And in the same cargo hold was a laboratory that will enable us to investigate as never before the strange properties of atoms when they are as cold as they can get. Just some of the science

going on a few hundred kilometers over your head. All our other regulars have the week off. Oh, not Bruce Betts. He'll be by to tell us about a truly magnificent night sky and we'll learn the name of his former band. There's still a lot waiting for you at planetary.org, including a wonderful collection of asteroids, metal asteroids, sitting on the surface of Mars. They're in a blog post from guest writer Linda Martell. Greg Holt works at the

Johnson Space Center outside Houston, Texas, where he is the Orion Multipurpose Crew Navigation Lead. Want to know where you are in space and how to get to that moving speck of light ahead of you? Want to know where you are in space and how to get to that moving speck of light ahead of you? Then Greg's your guy. He's also, though, the principal investigator for a project that has just put a sextant on the ISS. Simply put, this ancient instrument allows a trained operator to very precisely determine the angle between one object, let's say the horizon, and another, maybe the moon, sun, a planet, or a distant star. Knowing that angle can be the key to knowing where you are,

whether you're in the middle of the Pacific Ocean or on a spaceship that is halfway to Mars. Greg Holt, great to talk to you down there at the Johnson Space Center. Thank you for joining us on Planetary Radio. Thank you, Matt. Great to be with you today. I am especially pleased today to be talking to someone who, at least from what I have read, knows as much as anybody on this planet about how to get from here to someplace else without getting lost. I mean, is that a fair description? That's not too bad of a description, actually. I like to joke around with my team here in Houston that one of our big jobs is to answer the question when the flight director asks, dude, where's my spaceship?

We're on call. And this is a challenge that we face since the beginning of the space age, but really for far longer than that, because we want to talk about this marvelous device, this instrument that you have sent up, you and NASA have sent up on the most recent resupply mission to the International Space Station. Tell us about what you've got in mind sending a sextant to the ISS. Well, thanks. Yeah, it's really the ultimate application of standing on the shoulders of giants. Obviously, folks have been using sextants, these mechanical optical devices, to navigate on the high seas since the 17th, 18th century. So certainly nothing new on the technology, but the application of it to spaceflight is where things really get interesting, and especially because as we're traveling further and further away from Earth,

And especially because as we're traveling further and further away from Earth, traditional land-based aids such as GPS like we have here on Earth become less and less applicable. And we really have to go back to navigating by the stars and doing things a little bit more the old-fashioned way the further we get out. sending up a fairly simple device, but one that's very time-tested as a navigation aid, testing it as an emergency device when all the chips are down, when potentially computers and communications are lost. Having that nice solid piece of metal in your hand that you can use to affect your own rescue is really appealing to the crew. Did you work with the astronauts who will be attempting to navigate and find their position with this sextant? We did, in fact. We had the great opportunity to actually train this crew that is going to do the experiment for us on International Space Station

here coming up soon. Alex Gerst and Irina Anonchancelor were our two crew members and they did a great job. We started off the session telling them that astronaut means star sailors and they were going to get a chance to earn their stripes today as actual star sailors in the training. And when they do their experiment, they were very enthusiastic and I had a great training session with them and are looking forward to actually doing the operations with them on the station. You ever see the movie Master and Commander or read the terrific book series that it was based on? I have done both. Absolutely. You remember the scene in the movie where the captain is showing the young midshipman how to use the sextant?

Absolutely. Yes, that's a great scene. It's very applicable of the type of measurements that we're having the crew take. We're actually using the method of lunar distances for this experiment and also for Orion's use. It's a method of taking measurements between some distant fixed objects like the stars and some closer moving objects like the moon and the earth, and using that to tease out your position of velocity in that region between the earth and the moon where we're going to be hanging out for a long time on these Orion Deep Space missions. It seems to me that these earthbound sailors of a couple hundred years ago, and of course sextants are still being used by the U.S. Navy,

they had the advantage of that they only really had to work in two dimensions, where you have to teach people to work in three. Is that a challenge? It is a little bit of a challenge. And we're doing our best, obviously, for this particular application to try to make it as simple for the astronauts as possible. We're having them learn to take the marks. And then we're giving them quite a few post processing aids. Obviously back in the age of sale, they had to do all of the calculations by hand.

We're obviously going to let them have the advantage of calculator and, or even better, we're going to have a some tablets on board that they can use to help them with some of the data reduction that takes, take some of the time and also take some of the learning. So it's going to take a little bit of a learning curve away, having some of that pre-calculated all for them. All they have to do is just take the marks and put it in. But the actual physical skill of taking an accurate mark with a sextant is absolutely not unlike they had to learn back in the days of

master and commander. They obviously didn't have an app for that, but if you were to hand your sextant to one of these mariners of a couple of hundred years ago, would they pretty much know how to use it? Absolutely. The basic design operation has really not changed significantly since the 18th century there. And that's really a testament to the folks that designed that. They literally spent untold hours designing all the features into it that they would need into what's really a relatively compact and useful device for getting that type of measurement, those angular measurements that

you need to effectively perform navigation at sea, obviously, for them. But we're extending it all the way out to space. And even in space, there's some history for this. I found some video and some stills of Gemini astronauts and Apollo astronauts, right, who use sextants. In fact, on the Apollo command module, I saw astronauts using a sextant that was actually built into the capsule. That's quite true. The concept of using a sextant in space is nothing new. The records are spotty, but we do think that some of the early Vashkod missions out of the Soviet Union took a sextant along.

We do know that for sure, obviously that the Gemini missions were the first documented places where we had sextants used in space. Most famously, Buzz Aldrin on Gemini 12 took it up and did a very nice set of experiments there with a handheld sextant. And then for Apollo, they did, in fact, build in a vehicle integral sextant for a source of navigation. It ended up being the backup source of navigation to get the crew home in the event that they lost communication with the ground.

to get the crew home in the event that they lost communication with the ground. And Jim Lovell famously demonstrated that during his Apollo 8 cruise to and from the moon, where he did a fabulous job of taking sites that were as accurate or more accurate than we could radio track from the ground, had a little bit of a competition going there between the guys on the ground and how good he could sight from the vehicle. I assume that things may have improved a little bit since then, but maybe we'll get into that in a moment. Are you pretty confident that when humans finally head out to Mars, they'll have a sexant along for the ride? You know, obviously they're going to have to make that call. Each crew and each program has to decide what they want to take along as far as their emergency rescue equipment. We're doing this experiment to really demonstrate that this is a viable option

to them. And, you know, it's one of those things where, just like when you're going to sea for an extended period of time, you have your GPS units with you, but most good mariners will always have that mechanical backup that when everything else is going down and they're in a low power situation, you always have that last fallback that you can use to at least give yourself a fighting chance to get home or to make it to your destination. Yeah, we talk a lot on this show about robotic space missions and the absolutely amazing, spectacular jobs of navigation they do, getting all the way across the solar system and hitting tiny keyholes in the sky.

For human exploration of space, I mean, how have things changed since the days of Gemini and Jim Lovell showing that he might be able to do it better with a sextant than could be done from the ground? Yeah, that's a good question. Certainly, those robotic missions are absolutely amazing in their ability to really thread the needle when it comes to doing effective navigation across incredible distances. Truth be told, we've, in the human spaceflight regime, are taking full advantage of that. The advances in the Deep Space Network that have been made over the past 50, 60 years have been incredible. We certainly anticipate that Deep Space Network is going to play an

integral role in tracking human transportation vehicles well into the future. And having that asset there is going to be a huge, huge benefit. But one advantage that we do have over robotic missions as human transportation missions is we do have a crew that if worse comes to worse, they can always affect their own rescue, whereas the robotic mission has to stand by and only discovered as I was researching to prepare for this conversation, and that is that your sextant isn't the only one, in a sense, on the ISS, because I read about what's known as Station Explorer for X-ray Timing and Navigation, which is one of those wonderful NASA acronyms that comes out as sextant. Talk about state of the art or bleeding edge for perhaps for one day for humans to find their way around the solar system. Are you familiar with this? Yes, absolutely. Some of the good folks up at Goddard Space Flight Center have been

working on that for some time and did fly that up there. And boy, that's been a great tech demo mission, getting some really good data from that. I absolutely see that as one of the big next steps in autonomous navigation for, obviously not just for human spacecraft, but for any spacecraft, robotic included. The ability to give yourself almost a GPS-like system as you move out further into the solar system using these pulsars is incredibly exciting. And it really would be a great leap forward. And I'm really excited to see all the great results they're getting. It's the great technological leap forward for navigation. And it's an interesting compliment to see that mission against ours, which is purposefully trying to go the low-tech route, if you will, to be the very deep emergency backup.

And so, you know, kind of having those two complement each other is a nice, interesting juxtaposition on the station right now. Yeah, it sure is. Good on them for picking such a terrific acronym. Greg, it sounds like the romance of all of this, the charm of using a device that would be familiar to someone traveling the seas of Earth 200 years ago, it's not lost on you. No, absolutely not. I have to admit it's very nostalgic and very humbling, in fact, to realize that the same sort of activities were taking place hundreds of years ago and that the basic skills of the navigator there really translate so well to the modern space-faring age. Obviously we take advantage of all of the advances

in technology to give us very robust and capable autonomous and automatic systems, but much like the sailors at sea today still have that mechanical backup to allow them to affect their own rescue in a pinch. We're wanting to give the crew that same capability today. Thank you, Greg. It has been absolutely fascinating talking to you about this project and how we're using classical romantic technology now to find our place among the stars as Seaman did hundreds of years ago here on Earth. It really has been a pleasure and best of luck with this project. Likewise. My pleasure as well, Ben. Greg Holt is the principal investigator for

the sextant that is now on the International Space Station. But he is also the Orion Multipurpose Crew Navigation Lead at NASA's Johnson Space Center, working with all the people who are preparing the Orion spacecraft to travel far beyond low Earth orbit one day, and hopefully one day very soon. The Cold Atom Lab, or CAL, has joined the forest of devices, machines, gadgets, and assemblies aboard the International Space Station. Putting it there has been the dream of project scientist Rob Thompson and his team for a long time. Rob himself has been working with atomic and laser physics, along with quantum electrodynamics and other areas of research for over 20 years. along with quantum electrodynamics and other areas of research for over 20 years, he has believed for many of those years that the microgravity environment,

what most of us know as zero-g, may be the key to understanding the terribly strange things atoms do when they are a hair's breadth above absolute zero. Now he and we may finally unlock those secrets. Rob Thompson, welcome to Planetary Radio. It's a pleasure to get you in here as our guest at the Planetary Society. Awesome to be here. And not everybody gets to do this right after getting a personal tour from the science guy himself. And as you heard, he's a fan. He's a fan of cold atoms, which it sounds like you are too. I am a big fan of cold atoms. We're going to talk about Cold Atom Lab, which you must be very relieved to know has now taken its place in Iraq on the International Space Station.

Yes, it was very exciting to watch it. It had a beautiful launch and had a nice ride up to the station. And we got to interact with the astronauts as they were putting it into the rack. And it was incredible to see that come together. You were on live with the astronauts as they were? We were watching on video and team members were in contact with them, talking them through some of the procedures. Yeah. Wow.

Now I want to know, were you at the launch? I was at the launch as well. It was a great launch. Nighttime launch from Wallop. Nice. Probably my favorite place to watch a launch. Haven't done one there. Of course, I've barely done one anywhere. All right. We've got to talk about what this is going to do, but as an intro to that, because my guess is, sophisticated as our audience may be, some of them probably have never heard of a Bose-Einstein condensate. Please give us the two or three or four minute primer to what we're talking about here.

Well, as you get matter at very cold temperatures, you see something strange happen. And it's a quantum mechanical effect. That's not something you'd expect from classical physics. But if you get a gas of a certain type of particle called bosons, and most atoms are bosons, as you cool them down there, you start to see their quantum nature, their wavelength. Particles have both a wave and a particle nature, and you start to see that wave nature. If you get down to very cold temperatures, those wavelengths get larger and larger. And if your density is high enough and you're cold enough, they start to overlap. And when that happens, something strange happens.

The atoms, it's been described as kind of a quantum identity crisis. You know, a large fraction of them will fall into the lowest possible state and start behaving as a large kind of macroscopic object. You know. They're not individual atoms anymore. I've heard them described almost like a single super atom. One of the first people to discover them described them that way, as kind of a super atom. So it's still a quantum object. Most of us have heard a little bit about quantum mechanics,

but what we might think about it is it's the science of really small things, you know, atoms and molecules and subatomic particles. The interesting thing is that at these low temperatures, quantum mechanics can become larger. These can become macroscopically sized objects. So quantum mechanics is the science not just of small things, but also very cold things. Bose and Einstein. Einstein, we know. Bose, they worked together on this?

and Einstein. Einstein we know. Bose, they work together on this? Bose was a prominent Indian scientist and he gave a lot of thought to the statistics of how lots of quantum particles will interact together and he sent a paper off to Einstein and Einstein thought about it for a while and as he thought about it he said, oh this is, you know, one of the things that occurred to Einstein was that if that was true, if Bose was right, that you would see this Bose-Einstein condensate. And it took him a little while to decide to reconcile himself that all this was real and the math was right. But then he did finally help Bose get that published and get the attention that it deserved. And it's really one of the kind of cornerstones of modern statistical physics. But when that happened, they showed it was theoretically possible, but nobody had actually created one of these, right? Yes, at the time. I think Einstein

didn't even really think you would ever be able to get to those kind of cold temperatures. So it took quite a while. Before that, they had done experiments with superfluid helium, and people did say that that's a related phenomenon. It's a little bit more complicated because... Also really weird stuff. Also really weird stuff. And so it's related to superfluidity, it's related to superconductivity, but those are systems where the particles are interacting very strongly together,

and those long interactions kind of, to some extent, mask the pure statistical physics phenomena of Bose-Einstein condensation. How long have we actually been able to play with this stuff in the lab? 1995 was the first one made by Carl Wyman, Eric Cornell, and colleagues at the University of Colorado. Wyman, Eric Cornell, and colleagues at the University of Colorado. We're actually very excited to have Eric as one of our PIs, principal investigators, scientists who work with the cold atom lab. At the time, I was just starting my career as a postdoc with Bill Phillips, who was one of the first people to discover the technique of what's called laser cooling, using lasers to get atoms very cold. And that's one of the techniques that we start on, is using the things that he had discovered. But the exciting thing at the time was every lab that was doing this sort of thing around the world,

and there was probably 100 of them, you know, different universities throughout the world, everybody changed immediately and started doing those Einstein condensation experiments. So it was one of those experiments that everybody drops whatever else they're doing and says, oh, that's really neat. Many labs around the world started to do these experiments. I came to JPL a couple of years after that. It was obvious even from the beginning that gravity played a pretty big role, could perturb these experiments fairly significantly, and played a pretty big role, often kind of a deleterious role.

Almost right from 1997, 1998, we started thinking about doing one of these experiments in space, which was crazy at the time, and many people told us we were crazy because it really took a very massive lab full of equipment, huge amounts of power. It took a team of graduate students and postdocs usually kind of tweaking up these experiments and keeping everything running and repairing them when they broke down. The idea of doing that in space was crazy. Yeah, astronauts, they're really smart people, but there aren't a whole lot of them that are advanced physicists. Yeah, yes, and their time is pretty precious as well. So we had to work on developing a system that would be, once the astronauts have installed it, would be totally hands-off.

We control it from the ground, and the astronauts don't need to be bothered by it, but they still can help us out if we have a problem, if something does need to be replaced or fixed, they can do that. They also can upgrade the system. So we actually designed it to be a system that can be upgraded and have new modules kind of go in to do new types of science. What were the biggest challenges in getting this from what you said was a lab-sized experiment, experimental structure, down to something you could fit in a rack and run with the limited power available on the ISS. The power issues, some of that was new technology that had been sold kind of in the meantime to kind of miniaturize those little traps.

We trap our atoms with magnets, and you can make these actually pretty small. The nice thing about them being small is they are actually also much more powerful traps and at the same time much more, much lower power traps. So we kind of solve a number of problems at the same time. So that problem we and others around the world had kind of sold prior to the launch, but it was a massive packaging. As you might imagine, there's I think something like a mile or so of cables, you know, in this tiny little box and trying to figure out how to get them from one place to another. We certainly had, you know, our share of things that needed to be invented. is important is because the technology for very sensitive lasers and other types of techniques to manipulate atoms, very good vacuum systems. You can find examples of people who have flown this before, but not quite as complex a system

as we've put together here. The space station makes all this possible as well. One of the big things in the space station doesn't seem to get enough credit for how incredibly good it is as a lab. This is a shirt sleeve environment, so we don't have to worry too much about major temperature fluctuations and things like that. The space station, there certainly are some limitations on power, but it's pretty good compared to what we're used to, especially at JPL when we're really trying to save every watt when trying to send something to Mars or something like that. You're saying there may be, oh, right, compared to like sending a rover to Mars.

Yeah, yeah, yeah. Okay, now I get it. I thought you were going to say you had less power available at JPL than you did on the ISS. Yeah, no, no. Compared to a typical JPL space mission, it's pretty healthy. And capability of taking out the heat as well, which is also important. But the other thing that's nice about the space station, especially if you're flying inside the space station like we are, is you get to wrap the whole thing up in foam before you send it up, and you have the astronauts there to unpack it.

Nice. Rocket rides are, you know, they take a toll. Yeah, they take a little toll. So what's the status now on the ISS? It's only been there for, as we speak, about a month. It's about a month now, coming up on a month. And so we have done a basic hardware checkout. We have some cold atoms. You know, we've done, you know, the first steps of cooling atoms. Hardware is working extremely well so far. Not quite as cold as we're going to get them. The first couple of weeks really focused on hardware checkout types of activities.

Then the next big step is to try to optimize this system to work in microgravity. A lot of the different steps that we take to cool atoms are going to behave somewhat differently in microgravity to the way that they behave on Earth. So you have to kind of tune and tweak your system a little bit to get its performance optimized. So we're taking a sort of methodical step-by-step path through those processes to optimize it. But the science is coming. What is it about microgravity that gives you such an advantage doing this kind of work. The big thing about microgravity is we can let one of these samples go and we can just, it'll just sit there, it'll float in our apparatus. Yeah. And we can look at it for a fairly long time. Or if you want to

actually hold it, we can hold it with extremely weak forces. We don't have to, you know, fight against gravity to hold it. One of the reasons that's important is the last step of our cooling process. We have a three-step cooling process. I mentioned to lasers there's another step called evaporative cooling where we pluck off the hottest atoms and let the rest of them cool down. Actually, there was a Larry Niven, the science fiction writer, a Larry Niven short story where in a time of magic on Earth where a guy, an old wizard, lives in a cave, and he's got sprites or something that he's created.

And they actually, they grab the hotter molecules and throw them out of the caves. That's his air conditioning system. Ah, well, this is, yeah, he must have known a little bit about it. So yeah, we have, you know, these atoms are kind of bouncing around on a little, they're held in a magnetic trap. You know, we have, you know, these atoms are kind of bouncing around on a little, they're held in a magnetic trap. You know, we have atoms that can be prepared. Atoms themselves act like little magnets. And we can use radiofrequency or microwave radiation

to actually just pluck out the atoms that are in the highest magnetic field, which are also the hottest ones that have kind of climbed up the furthest up the walls. Got it. And we can pull those ones out selectively and let the rest of them kind of cool down. But the very last step that we do is we do something called decompression cooling. And there's a few different related techniques, but the simplest one to describe is taking that just, you know, we're holding them in this magnetic trap. It's really like you can imagine you have a little cup, coffee cup that's made up of magnetic fields and the atoms are kind of sitting at the bottom of this thing.

And we just expand it. We weaken the trap and we let the cloud expand. And as it does that, it gets cool. And it's the same type of phenomena when you spray on an aerosol can. Yeah. And you get cold air. Or like a refrigerator, the Venturion refrigerator. Yes, is that kind of expansion type of effect.

Yes. And that works well, and people do that on the ground, but you can only go so far on the ground because you have to support the atoms against gravity. And so we can go much further, and we hope much colder. You know, there's really not strict limits. We hope to get temperatures, you know, well below nanokelvin. Sorry, a billionth of a kelvin? A billionth of a degree above absolute zero. Absolute zero, yes.

Will that then be the coldest ever achieved, if that happens? It's a little bit colder that you have to get to. We are hoping that we get to make that claim. But yes, if we don't see it on the first try, we have some of our PIs have somewhat more advanced techniques to get us even colder. And yeah, ultimately, if you want to get really cold, space is the place to be. So that's only one of the reasons to be in space. The other reason is simply to be able to look at these atoms for longer times. For some types of experiments, essentially, it's it lets you look

for very weak effects. You might get masked on Earth. It also lets you make more precise measurements. In a sense, just Heisenberg's uncertainty principle. If you can look at something longer, you can measure its frequencies and energies better. This is sort of a, it's a platform. It's a workbench. It's not just one experiment. You're going to be supporting many experiments and many researchers. So, yeah, it's a multi-user facility. So we have five teams of researchers signed up to use it. You know, those are teams.

Some of them is probably about 20 or more individual scientists kind of working, including a number of very prominent members of the community. It's the Nobel laureates on the team. And they're doing a wide range of really neat stuff that kind of goes from the pretty far out there, you know, fundamental physics types of ideas and to things that are, you know, more, perhaps a little bit more practical. So we have folks that are doing things related to navigation, inertial navigation, rotation sensors, and things like that.

We have a team sort of looking at the fundamental nature of how quantum objects collide and looking for universal properties of those collisions when you have several atoms colliding at once. We understand very well how two atoms or two protons, neutrons, whatever, we understand that fairly well. But when you have three, four, five, it gets complicated fairly quickly, and it appears to be very interesting.

There's certain types of kind of universal phenomena that kind of emerge, so I can do an experiment with the experiment we will be doing, or our PI will be doing is looking at potassium atoms and how they collide. What they learn is actually applicable to all kinds of other types of particles because it's actually universal behavior of any quantum object. I like to say that this gives us some insights into just the nature of how complexity emerges in the universe. If you ask a particle physicist, they will tell you that the only thing that ever happens in the universe

is fundamental particles collide with other fundamental particles. If they're not colliding, they're just going on their way and nothing happens to them. And then they come upon another one and they can bounce and go in different directions or they can turn into other particles. But that's the only thing. These are particle physics. There's no chemistry. There's no biology. It's all just particles.

Yes. Exactly. But as far as we know, these guys are right. And not only we don't know the fundamental laws of the actual deep down secrets of fundamental theory of everything kind of thing. We're still searching for that. The opinion of most scientists is that ultimately that physics will be simple. It'll be simple rules, that fundamental particles. It'll just be a few fundamental particles and they'll interact by simple rules.

So how can you get this complicated universe? How can we get forests and galaxies and symphonies out of that simple physics? And so the idea is possibly that that is emerging when you have more than two atoms collide, when you have three, four, or five. So I think it's very important to study these types of systems. Some of the great mysteries of our time that have also captured the popular imagination, you mentioned theory of everything, grand unified theory. You might get additional clues for that? Or what about other stuff like dark energy or dark matter? Sure. You know, Cal itself is, you know, we're hoping it acts as something of a pathfinder for

a new type of experiment that we would be doing in space. Very high precision experiments, taking advantage of space to get huge increases in precision and sensitivity over what you can get on Earth. I mentioned that CAL is upgradable. The first upgrade that we're planning on flying, probably 18 months or so down the road, would be something called an atom interferometer. People may or may not be familiar with interferometers.

You might have heard of the LIGO gravity wave detectors. Those are, I think, the most precise experiments anyone's ever done. Those let light interfere. Those experiments where you send beams of light down different paths, you let them interfere. You can do the same thing with atoms because atoms, matter has this wave nature, and so you can use that wavelength dependence to make an atom in the far amateur. For certain types of measurements, these can be, especially if they're in space, they can be incredibly precise. So the precision, if you're trying to measure an acceleration

or trying to measure gravity, goes as a square of the amount of time that you get to look at the atoms. So if that can be 100 times bigger in space, we get 10,000 times more sensitivity. And so it is possible that this might take gravity wave research further? There have been proposals. So we're not doing any direct experiments on gravity waves with Cal, but scientists have proposed that this might be a possibility. Another experiment that we are looking for, and we hope to do at least a preliminary experiment on Cal once we have the atom interferometry capability, some of our PIs would like to do a test of Einstein's equivalence principle. And so the idea is sort of a repeat of the famous

Galileo experiment where he drops two cannonballs made out of different materials from the top of the Leaning Tower of Pisa. What we would be doing was dropping two atoms or dropping two samples of atoms. One would be rubidium and the other would be potassium. And we will watch those fall in Earth's gravity. We could then measure them, how far they've gone after a few seconds to extremely high precision, and then hopefully get a nice measurement. Ultimately, maybe get a really ultimate test of Einstein's equivalence principle in space. So what would happen if you tried that, when you try that experiment,

and the rubidium lands before the potassium? That's kind of stir things up, isn't it? That would stir things up. Of course, the big question when you do an experiment like that is, okay, if it comes out that they go at the same time, then you're safe and you can publish that one. If they fall at different rates, you need to go back and you need to look really carefully at whether there's something that would confound that measurement.

And you try different measurements and you try, you know, it's going to take a little work to get, you know, Einstein's hasn't been proven wrong in a long time. Not yet. You mentioned navigation. And I told you, I mentioned a couple of days ago that we're also going to be talking to a colleague of yours at the Johnson Space Center who's part of a project which is actually taking ancient technology, a sextant, and has put it on the International Space Station so that astronauts on the way to Mars or wherever, if everything else fails, they can do it the old-fashioned way,

sighting on stars. So I love the contrast with what you're talking about. How would something like Cal possibly someday help us navigate among the planets and stars? If you can measure gravity with an atom and defromator, you can measure accelerations. Einstein tells us this is the same thing. Acceleration and gravity are the same thing. So if we can measure that, it leads to something called inertial navigation. You can just, you know, you have your spacecraft in space and you know where it is at one point in time. And you know how it's accelerating after that. And you can figure out exactly where it is at another point in time.

Which works. It's on submarines. It's on airplanes. Yeah, it works. And we can also measure rotations, which is also important. And in space, ultimately, these will be significantly more sensitive than the current technologies that we have. The section experiment is we're on the same, shared the same rocket.

Yeah, yeah, yeah. And it's great to see the ancient form of navigation with what I think we'd say is the ultimate kind of cutting-edge type of navigation. Yeah, finding your way. Just one more potential practical application for the kinds of things that you may learn if Cal does what it's supposed to. What about quantum computing? Will it contribute? We don't have any direct experiments on the first, you know, set of PIs to do quantum computing, but a lot of the technology is similar, is similar, at least for certain classes of experiments that folks are doing in quantum computing. And it's a somewhat unique platform

where one of the main issues with quantum computing is something called decoherence, where you need to put information into these quantum states. You map it into these qubits, and they're very sensitive to any interaction with their surroundings. By putting something in space, we can isolate it very well. We don't need to have forces kind of pushing on those atoms. We can just kind of make them almost arbitrarily weak, because we don't have to fight against gravity. So that might let one minimize those things. It might let you study those types of processes in a different regime.

I suspect that no one's going to be building full-fledged quantum computers in space, but who knows? Maybe the advantage will be so big that people will say, that's where we need to build them. But a lot of that same technology is applicable. And even if we don't get any practical applications out of work done by Cal and your team and these other teams, there's something pretty exciting about adding to our knowledge of how everything around us works. This is something I've been working on for almost 20 years, kind of pushing toward this type of experiment.

We call it the coolest spot in the universe. It's NASA's coolest mission in a literal sense at any rate. I think it's going to be exciting. But I really do hope that it does something, opens up the future for some types of experiments that will really make a profound difference in our understanding of the universe. You said that there's one more experiment that you like to talk about? I like to talk about it, yeah, for a couple of reasons.

It does a really good job of illustrating what you can do in microgravity and why you can't do it on Earth. And this is a researcher, Nathan Lumblad from Bates College, who's doing an experiment to make bubble geometry Bose condensates. So these are quantum bubbles. They'll take a spherical, hollow kind of spherical shape. You can't do this on Earth because you can make the same potential on Earth that would allow atoms to go, but the atoms will just clump on the bottom of it.

They won't flow up and make the full bubble. Once he has that, he'll be able to look at how uniformly it fills the sphere and how he can look at the dynamics of how it behaves and things like that. If we let him, he would have years of experience to do on that. A lot of the interesting things that have come out of Bose condensation has happened when you change the topology and things like that. It's one of those things I can't necessarily promise anybody it's going to be useful for anything, but who knows? You never know.

You never know. What would be in the center of that sphere? Vacuum? It would be vacuum, yeah. It would be vacuum. Fascinating. All right. How long before the real science starts to come out of Cal?

So we're in a commission phase where we're kind of checking everything out, and we hope to have that wrapped up in two more months now. So in September, October, we hope to be switching over to bringing the scientists on board and doing their experiments. Best of success to you. And, you know, maybe after some of that science starts to come back and people start preparing papers for publishing, I'd love to talk again. Yes, I would love to come back. I'm hoping there'll be a lot to talk about.

Thank you, Rob. Stay cool. Okay, thanks for having me. Rob Thompson, the project scientist for the Cold Atom Lab, which has taken its place on the International Space Station and is starting to achieve some of those extremely frigid temperatures that are going to help us understand our universe better. Time for What's Up from Planetary Radio and the Planetary Society. We've got Bruce Batts, the chief scientist of the Planetary Society on the line. Welcome. And I have a special message for you. Well, really for both of us. That's good, I think. Yeah, you may want to reserve judgment. This is from Santino Jaime. He entered the contest,

but he also included this message on behalf of all Alaskans, he's in Anchorage. On behalf of all Alaskans for space exploration, we thank you for empowering, educating, and exploring. Nice, right? Yeah, very nice. Yeah, but then he says, also, did Bruce used to be in a hair metal band? If not, he should be. Defined band. Now, this is fun because we have a reference to, I don't think they're a hair metal band, really,

but a very famous band will come up when we do the contest later today. It's your turn. What's up? Little known fact, I was in a band called Psycho Salad Bar. Are you serious? That's not important right now. I did not know that. I didn't even know that you played an instrument. Or do you?

Do you need to be in a hair metal band? Not in one called Psycho Salad Bar. All right. Well, we'll get more on that in a future episode. I doubt it. Okay. So planets, I know I've been excited, but I've added another planet just for your enjoyment. So Mercury, now visible in the early evening, shortly after sunset.

You'll find Venus looking super bright. Look to its lower right. Soon after sunset, you can pick up Mercury, which means that all five planets you can see with just your eyes are up right now. So we got Mercury and Venus, I mentioned, and then Jupiter up in the south looking really bright also, not quite as bright as Venus. And then over to Saturn looking dimmer, but cool. And then Mars coming up a little while after sunset now, but we're approaching Mars' closest approach in 15 years on the 31st, and Mars' opposition opposite side of the Earth from the Sun on July 27th. So much going on.

We've got the moon, crescent moon, hanging out by Mercury on the 14th of July and Venus on the 15th of July. But wait, don't order yet and I'll get you more information. But also July 27th, there is a total lunar eclipse pretty much on the opposite side of the planet from where Matt and I are. But if you're in lots of Europe and Asia, Africa, other places, I'll define that next week or you can check online. You got a total lunar eclipse. Oh my gosh, that's a lot of stuff. That is a lot of stuff. And you know, about a third of our audience is elsewhere, outside the United States, many

of them in Europe and those other areas you mentioned. By the way, does that appearance of Mercury, is that an exclusive offer available only to listeners to Planetary Radio? Yes, it is. We're subliminally implanting in your brain the ability to see Mercury. No one else will be able to see it if they haven't

listened to the show. We are so good to our audience. All right, go on. It's a benefit. It's a bonus. Go Planetary Society. Hey, this week in space history, also an exciting week. A couple things I will mention. 1965, Mariner 4 became the first Mars flyby.

2015, New Horizons became the first and only Pluto flyby. Mariner 4, the spacecraft that made Ray Bradbury's life much more difficult. I'm not going to explain it. Thank you. We're all about information on this show. Speaking of information. Random Space Fact. Wow. Did you do that on stage? Define stage. So anyway, if the solar system were the size of a U.S. quarter, the Milky Way would be the size of North America. Wow. That's great.

That's very good. You know I love those. I know you do. I know. I'll try to do more. Thank you. All right. We move on to the trivia contest.

And I asked you, why is the near-Earth asteroid Hayabusa 2 is visiting named Ryugu? How'd we do? I have been waiting for Random.org to pick the person that I believe is today's winner. Why? For purely selfish reason, which I'll go into in a moment. But Random.org selected Ryan Parmenter from the many entries that we got. He's in Georgetown, Texas. He says, Ryugu, meaning Dragon Palace, was named after a Japanese folktale. In this story,

a fisherman travels to Ryugu, a magical underwater palace, and returns with a mysterious box, much like Hayabusa 2 will return with mysterious asteroid samples. Close enough? Exactly. I love it. Ryan, congratulations. And thank you for the good work you are doing. Ryan, I know from previous messages, is a SpaceX guy.

And I believe he's working on the launch of STP-2, that second Falcon Heavy that will be carrying LightSail 2. He adds GoLightSail 2 and go Falcon Heavy. Yeah, I concur. Good job. Keep it up, Ryan, and there'll be a lot of us in Florida at that big launch. Hopefully standing somewhere near you, be sure to introduce yourself if you're down there for the launch.

I've got some other stuff, by the way. Oh, I should mention that Ryan is going to get a military radio T-shirt and a 200-point itelescope.net astronomy account. Mark Little in Northern Ireland. This is where the band comes up. Dr. Brian May, the lead guitarist of Queen, PhD, astrophysicist. He released the first stereo photograph of Ryugu on June 27, 2018. And we'll put up the link to his blog where you can actually see this stereo image. The image is taken by Hayabusa2, Brian May. Awesome. And we've also got Ryugu image stories on our website at planetary.org. Excellent. We'll put up links to those too. Laura Dodd up there in Eureka, California, way north of us. She says, of course,

the fishermen opened the box back home and he had apparently been away a hundred years, but had not aged at all. But when he opened the box, he immediately aged a hundred years. She says, I'm not sure what that says about what we should or should not do with the asteroid samples.

Hmm. Quandary. Whoever opens the box suddenly ages four and a half billion years. Oh, maybe it'll just be the length of the trip of the spacecraft, a few years. Yeah. Robert Klain in Chandler, Arizona. He says, Ryu, goo to this asteroid to collect samples. Sorry, couldn't resist. the one that I'm reading, on a turtle's back, would I then get a box with a Planetary Radio t-shirt in it? Though in this construction, Society HQ would actually be an underwater

palace, which it isn't, is it? Well, let me just step outside my door. Splash! That pesky airlock malfunctioning again? Yeah. We're working on gills for everyone. I can't wait. I can't wait for the next contest either. Well, you know, it's going to be about Mars because Mars gets much dimmer and brighter every little more than two years because of the orbits of Earth and Mars. But also from one close approach to the next, it varies considerably in closeness and brightness. And that's primarily because Mars's orbit is not particularly circular.

It is eccentric. So dig into your analytical geometry and get me the eccentricity of Mars's orbit, basically saying how a numerical quantity for how not circular it is. Eccentricity of Mars's orbit. Basically saying how a numerical quantity for how not circular it is. Excentricity of Mars's orbit. Go to planetary.org slash radio contest. You've got for this eccentric answer till Wednesday the 18th. That'd be Wednesday, July 18 at 8 a.m. Pacific time. Do I have? No, not yet. We're soon going to have some other sorts of prizes to give away. But, you know, there's nothing wrong with winning a Planetary Radio t-shirt that you can check out at chopshopstore.com in the Planetary Society store or a 200-point itelescope.net account. iTelescope is the worldwide nonprofit network of telescopes. That account will get you

a couple hundred dollars. You can donate it to a school or a nonprofit as well. We'll help you out with that if you're the winner. Excellent. All right, everybody, go out there, look up the night sky, and think about what would your eccentricity be? Go out and look, and I'm so eccentric, man. Thank you, and good night. Clearly, my eccentricity is every week talking with the chief scientist of Bruce...

of the chief scientist of Bruce Betts. I suppose you are. The chief scientist of the Planetary Society, Bruce Betts, here on WhatsApp. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its old and new, but never blew, 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 at Astra.