Image credit: NASA; ESA; G. Illingworth, D. Magee, and P. Oesch, University of California, Santa Cruz; R. Bouwens, Leiden University; and the HUDF09 Team
Where did all the monopoles go? Do other planets have auroras? Can binary stars host planets? I discuss these questions and more in today’s Ask a Spaceman! A very special edition recorded in Vik, Iceland, where I answered questions from the AstroTourists who joined me for the excursion.
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EPISODE TRANSCRIPTION (AUTO-GENERATED)
What you guys are about to hear is a very special edition of Vasquez Spaceman recorded in Iceland during the Astro tour where I did thirty minutes of spontaneous q and a. I had no idea what these people were gonna ask. I had no idea what my answers were gonna be until I started giving the answers. So it's completely free form, completely spontaneous, completely a surprise. I hope you find it as fun and entertaining as I do.
I love doing live events. I love doing live q and a. And this is the second half of a special series. So the last episode I did was about a topic that I picked a question I asked myself about why is Iceland so warm. Some of the questions reference back to that talk.
So if you wanna go back and listen to that, if you didn't catch it before, go catch that one because it's really special and super informative as always. And then you can come back and then some of the questions are gonna make more sense. And before it gets started, of course, I have to do the Patreon pitch. Patreon.com/pmsuder. That is how you keep this show going.
Special thanks to Robert r, Justin g, Matthew k, Kevin o, Justin r, Chris c and Helgen B and all the other fine patreons for keeping this show going. Remember, askaspaceman@gmail.com, hashtag ask a spaceman. Go to askaspaceman.com for links and show notes and ways to ask questions and just all the juicy stuff. Without further ado, here is thirty minutes of random space questions and my answers to them. Alright.
Thanks so much for listening, actually. It it was a a pleasure to share all this with you, and I've been having so much fun talking to all of you about your perspectives, what you have been thinking, questions you have been having as we've been going on this adventure together. What questions do you have right now? How do we know what gases are on these other planets? Because we can't sample them.
We can't, like, taste them. Right. Yeah. No. That that's an excellent question.
How do we know when I say, oh, this is a nitrogen glacier. Oh, that's a cloud of sulfur on Jupiter. Like, it's no big deal. Right? But that's a huge deal.
That's ridiculous that we I can even say something like that. And we know what stuff in space is made out of because of this wonderful trick of nature that we call spectroscopy, where every atom, every molecule has a distinct fingerprint of light that when you shine a light on it or you heat it up and it glows of its own, it doesn't emit all sorts of colors across all wavelengths. It emits very, very specific colors. It'll emit one very particular wavelength of red, another very particular wavelength of green, maybe a little very, very particular wavelength of infrared or ultraviolet or whatever. It's very distinct pattern.
In every molecule, every atom, every element has its own distinct fingerprint. So if you have yellow street lights in your neighborhood, those are sodium light bulbs. They're heated up sodium. Sodium gives off a very particular color. And we can play this game here on Earth so we can match fingerprint light pattern to element, fingerprint light pattern to element.
And now that we know that physics is universal, when we see sunlight scattered off the surface of Pluto or of Jupiter, we can look for the telltale fingerprints of particular elements. And so we can say, that's nitrogen because I know what nitrogen looks like and I know what sulfur looks like and I know what ammonia looks like. We can We play this game in our solar system. We play this game across the universe. We can look at a different distant galaxy billions of light years away and say, oh, yeah, yeah, yeah.
There's some, there's some water in a molecular cloud out there. Or this star is has a a tiny bit of iron in it. We can do this. It's an amazing fact. We figured this out in the mid eighteen hundreds and it 100% unlocked astronomy.
One hundred percent changed the game for astronomy. Instead of just measuring star positions in these cloudy nebula things and cataloging them to being able to say what they're made of. Excellent question. Yeah. Does the fact that the Earth in its elliptical orbit is closer to the sun in winter here, does this add a bonus to the temperature of Iceland, for example?
Right. So it's contribution Right. So the Earth's orbit around the sun isn't perfectly circular. Sometimes it's a little bit closer. Sometimes it's a little bit farther.
The ellipticity of the Earth, the measure of how not circular it is, is almost zero. The Earth is almost perfectly circular in its orbit. And so the our variation of the distance from the sun hardly plays any role in climate or in weather. It's driven our weather is driven by the tilt of our axis. If we had a different tilt, if we are tilting more towards the sun or more perfectly up and down, we would have a very, very different weather system in totally different climates on different regions of the globe.
It's driven by our tilt. That's an excellent question. Yeah. You mentioned several worlds in our solar system which are which have is in large measure they're characterized by having glaciers of one chemical or another and volcanoes showing one chemical or another. How often is this the case and what would characterize this characteristic of a world versus one that would not have glaciers?
Oh, that's that is a good question. How do we characterize I showed you all the cool active worlds, but are they dead boring worlds out there in the solar system? The answer is yes. Moon, not incredibly interesting geologically, unless you're like a moon scientist, then it's the most fascinating thing in the universe. But for most people, it's like, oh, it's the moon.
Mercury, not incredibly active. Venus used to be active, now appears dead. Mars used to be active, now dead, still has some glaciers going on. Most of the moons of the outer solar system are just piles of rock with a bunch of craters. There are some special cases though where geological geologically interesting things are happening.
In order to have a geologically active world, you need heat differences. You need, say, a hot core or you need some sort of atmosphere. You need something to transport energy from one place to another. If you're if you took the moon and put it close to the sun and then the sun just baked the moon, well, the the moon is just about an airless rock. There's not gonna be a lot of transport of energy to start mixing things up and making interesting things happen.
But the Earth is hot on the inside, cold on the outside. The Earth has an atmosphere. The Earth has water oceans. So it's able to move. It's able to transport energy from one place to another.
And that gives you all sorts of interesting things. It gives you geology, gives you tectonics, gives you glaciers, gives you snow. It's By the way, it's snowing on Pluto right now. Pluto has an atmosphere and there's literal water ice falling out of the atmosphere as snow. Pluto is very cold.
It's at the distant edge of the solar system. But for some reason that we don't understand it's hot in the center, because it's hot in the center, cold on the outside, something interesting can happen. The moons of the giant planets like Io and Europa, they get hot cores because of their orbits around those gas giant planets. That's able to do something interesting that you wouldn't normally able to do. It's differences in energy that matter.
Excellent question. Yeah. Why do you think Pluto's hot? Why do I think Pluto's hot? I honestly have no idea.
And Alan Stern, the principal investigator of New Horizons who who led the mission, I asked him because I thought he might know and he didn't know. Because there are objects in our solar system that are about the same size of Pluto, even closer to the sun, are totally dead. Why is Pluto still a little bit warm? We don't fully know. So you mentioned about the gravity of Jupiter heating up the moon Mhmm.
In the course. Why would that not be the case for, like, Mercury or Venus? Okay. Good question. Why is the the gravity of Jupiter heating up the moon course?
Why doesn't this apply to planets close to the sun like Mercury or Venus? It's not just the fact. I slipped over this a little bit when I was talking, so but now I have the perfect opportunity to go into more detail. It's not just the fact that you have a moon orbiting a big object. That's not enough.
What matters is that there are also other moons orbiting Jupiter. Europa and Io aren't alone. There's Ganymede, there's Callisto, and there's a bunch of small ones. These other moons tweak the orbits of each other. And they tweak it in such a way that normally, Io, Europa, these worlds would want to follow perfectly circular orbits around Jupiter.
Eventually, that massive gravity would just circularize that orbit very quickly like within a million years which is very quickly astronomically. But because there's other moons, you get little tugs every once in a while that tweak it outside of that circular orbit and they transform these orbits into elliptical orbits. They're kept in what's called a resonance where they're locked into elliptical orbits. And now you have a world that sometimes is closer to Jupiter, sometimes further away, sometimes closer, sometimes further away by a lot. And so the core gets stretched and squeezed, stretched stretched and squeezed.
This flexing, this tidal flexing of the core of these worlds keep them hot. So if you're a very a moon very, very far away from the gas giant, you don't get this. You have to be close. There have to be other moons. Mercury doesn't get it.
Venus doesn't get it because there's nothing else to tweak those orbits. Great question. In the back. Do you have we are there auroras anywhere else? Like other planets, other like that magnetic core that would cause Right.
Great question. Are there auroras anywhere else? So Mercury has incredibly weak magnetic field. So even though it's super close to the sun, no aurora. Also, no atmosphere.
So it's it just hits rock and it's kinda boring. Venus has a huge atmosphere which would make for greater aurora but no magnetic field. Mars has a little bit of an atmosphere but no magnetic field. Jupiter, big giant gas giant atmosphere, giant magnetic field, spectacular aurora. Saturn has a magnetic field but it's even further out from the sun so that solar wind is gonna be incredibly weak.
I believe it has Saturn has faint aurora but not very strong. Uranus and Neptune, same deal. They're too far out. The wildest thing is we know of exoplanets, planets outside our solar system. We've been able to detect aurora operating on giant planets outside our own solar system.
So aurora are incredibly common. Yeah. What what sort of simple questions are being asked right now in your area of research in the cosmoids? Oh, great question. What are some of the simple questions I'm trying to answer right now?
Personally? So I'm a cosmologist. I study the large scale structure of the universe, its growth, its history, its evolution, its contents. And one of the simplest questions we've been asking for a hundred years in cosmology is, what is the universe made of? What is it made of on the grandest of scales?
What's the census of all this stuff? And because of general relativity, general relativity connects what the universe is made of to the history and evolution of the universe. So studying one tells you about the other. If you can understand how the universe has evolved in thirteen point eight billion years, you understand what it's made of and vice versa. And this is introduced asking this question, what is the universe made of?
Introduces us to dark matter, introduces us to neutrinos, introduces us to dark energy. To all these exotic phenomena that are at the forefront of physics research come from a very simple question of what's the universe made of? Yeah. What kind of I'm not quite sure how to ask this. Technological advancements are going to be needed to investigate Pluto more?
Yeah. So new This is causing No. That's such a great question. What do we need to go back to Pluto and study it more? So New Horizons.
New Horizons was launched in 02/2006, spent nine and a half years traveling to Pluto, nine and a half years traveling 36,000 miles per hour, one of the face fastest spacecraft ever. It spent fifteen minutes at Pluto. Fifteen minutes. And the day before, they had a computer malfunction and they had to restart the software systems the day before. That was a real nail bite nail biter.
They had one shot, 15. The mission isn't over by the way. New Horizons is now headed to the outer reaches of what we call the Kuiper Belt, has selected a target. In eleven months, it will reach its next target. Spend like ten minutes there and then it's done with its mission.
The challenge with Pluto. New Horizons was a relatively small spacecraft. It's the size of a of a baby grand piano. And they attached it to the at the time, the most powerful rocket we had to get as fast as we could. When you send something to the edge of the solar system at 36,000 miles per hour, there are no breaks.
There's You can't slow it down. You can't pack fuel to like do a burn and go into orbit. It's just not feasible with our technological levels. So your question was, you know, what would it take next? I honestly have no idea.
Pluto is such a hard target because it is so ridiculously far out. Can we do orbiters around Jupiter like we have orbiters around the gas giant planets? Can we do landers around Pluto like we have landers in the inner worlds? That is a very, very technologically challenging thing. It's certainly possible someday, but you might end up with an orbiter that all it has is a tiny little, you know, this digital camera attached to it and a little radio transmitter.
That's all the science you're gonna get out of it because 99.9% of it went into fuel and rockets. It's a tough problem. It really is a tough problem. So probably for all of us, this picture of Pluto is all we're gonna get. There are no planned follow ups.
There are no planned New Horizons, the sequel. This is it. And the mysteries we have are gonna be the mysteries we have. I would think that just the fact that they've discovered what they have is just the spark. You'd think so, but then there's politics.
All different. Yeah. Go ahead. Oh. Either one.
You can solve at the same time. It's cool. So that Venus does not have a magnetic field, how does it hang under that its atmosphere? Oh, great question. Great question.
Venus has no magnetic field. Mars does not have a magnetic field. Mars has essentially no atmosphere. Venus has an incredibly thick atmosphere. What's the deal?
I mentioned our force field which gives us the aurora. This force field also protects our atmosphere. If you were to turn off our magnetic field, then our atmosphere would be naked against the onslaught of the solar wind, these high energy particles streaming from the sun, and it would just blow it away. Like blowing on a dandelion. Just It would just be gone relatively quickly over, you know, ten million years or so.
So why does Venus with no magnetic field at all have such a thick atmosphere? We're not 100% sure. Venus is rather large. It's much larger than Mars is. So it has a nice strong gravity that can hold on to a lot of atmosphere.
It doesn't have any light stuff in its atmosphere. It's pretty thick. It's mostly carbon dioxide, bunch of sulfur in its atmosphere, some heavy stuff that isn't easy to blow away. And maybe because it's just so darn thick in the first place that even though the solar winds been blasting it for a few billion years, there's still a lot left. So there's there's definitely mysteries there too.
Why does it not have a magnetic field? Why does Venus not have a magnetic field? We don't know. We don't know. We know that Mars used to have a magnetic field.
Mars used to have oceans. Mars used to have an atmosphere, rivers, streams. We can tell that because you see all the geology around here of how the landscape is formed by all these rivers and glaciers and hydrologic features. We see these exact same features on Mars, just minus all the water, which means it happened a long time ago. So we know Mars had water, we know it had an atmosphere, it was warm enough to support a magnetic field, but it cooled down because Mars is small, lost its magnetic field, lost its atmosphere, its oceans evaporated.
Now, it's a bone dry desert. Why did Venus either not get a magnetic field or have a magnetic field and lose it? We don't know. Earth is special. Earth is special.
Yeah. So around extremely massive and large stars like Canis Major, do we know if there is, thousands, hundreds or thousands of objects going around those stars such as smaller stars, not in a binary or tertiary system, but just as if they were planets. We have smaller stars and those stars have even smaller stars and those stars have planets going around them and those star planets have moons, which have moons, which have moons. And you just get it. It's turtles all the way down.
Yeah. Yeah. Great question. So, you know, I I talked about how these planets orbit the sun and the planets have their moons and we visited some very interesting places just a little bit ago. There are some massive stars out there, you know, hundred up to a hundred times more massive than our sun.
Do they have stars orbiting them or their planets orbiting those stars and then moons orbiting those planets and then moonlets orbiting those moons and, you know, on and on and on. The answer is is yes, but kind of. We there are binary systems. In fact, most stars in our galaxy are in a binary system. Most stars in our galaxy are in a binary system.
There are triple systems, quadruple systems. I believe the largest known is, 17 16 or 17 stars in a single system, all gravitationally orbiting around each other in a very complicated dance. We know that there are planets around binary stars. Our nearest neighbor, Proxima Centauri, is a triple system or a member of a triple system and it has planets around it. So there's planets around a star and the star is orbiting two other stars that are also orbiting each other.
You it's not like, it's a free for all Because of the complicated gravitational interactions, there's only a few stable configurations available. If you just toss in like a video game, like I'm gonna toss in a bunch of stars and a bunch of planets like this, most of the time they're just gonna scatter off each other because of the complex gravitational interactions. There are a few stable arrangements. Absolutely. So you could have stars going around with massive stars like near the planets?
Absolutely. Absolutely. You can have stars orbiting larger stars. In the back. Yeah.
Again, considering what we know about these other worlds and how they're similar to ours in some respects and not others, what does that tell us about what could happen when we have a melting of, glaciers in Greenland and Antarctica, and the water from them flows into the ocean and thus reshapes the gravitational measure of the Earth so that different parts of the Earth are now heavier than they used to be and others are lighter. Does that alter the way tectonic plates move? And what does that then portend? Oh, yeah. That's a really, really fun question.
So can we learn it? Because as we observe other planets, other moons doing their interesting cool things, and then we look back at our own Earth. So the story I told a little bit ago was about taking physics we learn here on the surface of the Earth and applying it across the universe. You can play that game in reverse. Absolutely.
So when you look at things like glacial melting, does that affect the mass distribution of the planet? Does it introduce extra wobbles or weebles or whatever? And does that affect our magnetic field? Does that affect does the sea level change? The answer is, in that particular case of can we learn things from other planets and apply it to our own case of global warming, climate change?
The answer is kind of no. We seem to be a relatively special case. I will say that Venus, with its choking thick atmosphere, is a classic example of a greenhouse planet where there was a runaway effect, where the atmosphere just built and built and built and built, made it hotter, which made more atmosphere, which made it hotter, which evaporated more stuff, put everything out into the atmosphere and choked itself to death, which is we we don't want to happen here on Earth. So there's a case study right there. In the in the case of, you know, in this general question of can can sea levels affect the the tectonic action?
Can say the the glaciers over Greenland, if they were all to melt, what would happen? This can absolutely affect the tectonic action of the Earth. So most of not most of Greenland, a good chunk of Greenland is actually below sea level because you have these massive piles of ice that are literally pressing down on the continental material. If you were to melt all that, then it would spring up and that would change the underlying geology of what's happening underneath Greenland and Iceland. It would affect this environment in the North Atlantic and then it might cascade down to other parts of the Earth.
So there is an interplay between the water on the surface of the Earth and the rocks on the surface of the Earth and what's happening underneath the surface. Absolutely. Question. Can I ask you about the Earth's Earth's magnetic field? You can ask me about the Earth's magnetic field.
Yeah. I know it's diminishing, and I believe that in the past, it's flipped north south because this kind of twist around me so often. I don't know how frequent it is because they I think they found it in Atlantic, don't they, these ridges which show different magnetic polarity. Yep. What, could you know how frequently and quick that flip occurs?
Because when it does, it's gonna affect that magnetic field and then Mhmm. We could be in trouble. We might have to worry a little bit. Yeah. I mean Yeah.
Is it just radiation satellites? Right. This is a Yeah. A great question about about our magnetic field, how it changes, how it can diminish, how it can grow, how it can change direction. I We have this image and I think I gave the image of, like, the Earth is a giant bar magnet, like a big piece of iron sitting inside the core of the Earth and that gives us our nice magnetic field.
Well, that's not the case at all. It's actually very complex interactions. We have a very hot core that's spinning rapidly. This hot hot core is primarily made of iron, which is electrically charged, and that creates what's called a dynamo, which generates this impressive magnetic field. But since it's a ball of hot rock that's spinning around, that's gonna change.
Sometimes it can flip over, sometimes it can weaken and then strengthen back up again. So we see the Earth's magnetic field is not static at all. It is changing with time. We have evidence actually from the Mid Atlantic Ridge that runs right here through Iceland. We can see how there are some rocks that respond, that align themselves to the magnetic field, and we can see when the Earth used to be have the North Pole up and the South Pole down, in a when it used to be flipped, when it used to be gone for a while, when it came back, when it used to be stronger.
We're actually tracking the North Magnetic North Pole is actually moving right now as we speak. It is I forget the speed. It is tracking its way across Northern Canada right now. It is changing in time, in in the time that humans can measure these things, we can track these changes. It gets weaker.
It gets stronger. It always seems to come back. It's never gone long enough for our atmosphere to blow away because we still have an atmosphere after four and a half billion years, which means we've must have had magnetic field for a very long time since we've had the atmosphere. So we're not too concerned. The birds might get a little bit confused for a while, but I'm sure they'll adjust.
And then we'd have to take all our compasses and just replace the label, the north label with the south label, and then we'd be pretty much golden. And so there'd be those kinds of effects. Even in the fact that the Earth's magnetic field is constantly changing is something that is just a fact of nature. Yeah. Is that the reason why they repainted the numbers of the landing strips in airports?
Because this is Yeah. Expresses the angle to the new So, every every few years, airports around the world, depending on the situation, have to either lay new strips, landing strips, or, take off strips or repaint them. They do it for two reasons. One is because the compass heading changes and even though there's all sorts of fancy electronics like GPS and and lasers and whatever pilots use to guide themselves, it never hurts to have a triple, quadruple backup when you're flying a metal tube through the air carrying a hundred people. So, yeah, they will repaint them because the magnetic field is changing, and they'll also repaint them and have to reposition them based on the prevailing winds because you don't wanna land a plane when the wind is going sideways.
And if that's the only airstrip and then now the winds have changed, you have to realign them. So, yeah, they're constantly having to change themselves to update themselves with the changing conditions of the Earth. Yeah. So, can you talk to someone about the latest science on planets that have been extrasolar planets we know that are tidally locked to their suns? Right.
So extrasolar planets, planets outside the solar system, there are a lot of planets outside the solar system. Our galaxy alone is thought to host around a trillion, you know, plus or minus couple hundred billion. We're not too sure on the number, but around a trillion. Around a trillion planets outside the solar system. We're finding every kind of planet you can imagine in every kind of scenario.
You know, survey a hundred science fiction authors, ask them to make up a planet, all of those planets are represented by the ones we found. We've detected solidly a few thousand, around five or 6,000, and and we're finding all sorts of crazy scenarios. We're finding we're starting to find a lot of planets that are relatively small, orbiting sun like stars or stars that are smaller than the sun. If the star is smaller than the sun, like a red dwarf star, we're especially interested in planets that might host life, that might have liquid water on their surface. In order to do that, you can't be too close to the sun or you get totally baked or you can't be too far from the sun or you get locked in ice.
You have to be just the right distance from your star to get just the right amount of sunlight and balance of internal heat and all that good stuff so you can have liquid water on your surface. But if you're orbiting a very small star, let's say a tenth the size of our sun, then that habitable zone where liquid water can exist is like right up against the face of that star. It's right there. And in this case, when we're finding planets in the habitable zone of small stars. But in when this case, they're very likely to be what's called tidally locked.
They're going to have the same face always pointing towards their parent star. And this raises questions about the habitability of those worlds. If the Earth were locked around the sun, where say the Western Hemisphere was 100% daylight all the time year round and the Eastern Hemisphere was 100% permanent night, would life be able to get a foothold? How much does life depend on the circular patterns, on the weather patterns, the changing but repeatable patterns of Earth of of the of the weather and climate on the Earth? That's an open question.
That is an open question. We don't know. We don't know because we only have this one example of life in our particular set of conditions.