Q&A 161: Could You Have a Planet Made of Water? And More...

hey everyone welcome to the question show uh your questions my answers as always if a question pops into your brain anywhere across my channel just write it down i'll gather a bunch of them up and i'll answer them here i record the show every monday at 5 00 p.m pacific time live in front of a internet audience so if you want to watch this you want to come join ask questions live i'd love to have you hang out uh with uh with the rest of the people and it's a good sort of back and forth and lots of follow-up questions a lot of fun um now a couple weeks ago i mentioned the newsletter which i'm hoping you subscribe to the newsletter um but the other thing i want to recommend of course is the podcast that i do so if you're too busy to watch youtube videos and seriously like who has time to watch youtube videos then i highly recommend you subscribe to my podcast and it's a essentially it's just an audio version of everything that i do so all the interviews all of the question shows plus all 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would hold together and form hydrostatic equilibrium just as if you had a planet made of rock or anything gravity is gravity it wants to pull things into a sphere and it would do that with a sphere of water but it wouldn't be this sort of perfect floating sphere of water it would be this weird thing because in the cold of space it would be covered in a thick layer of ice and then beneath that you would have some point where the water hadn't frozen you you'd have like an ocean but you'd also have this incredible pressure in temperature and it would get hotter and hotter and hotter as you move to the center of this sphere of water and so you would form these weird versions of ice like for example we've learned that you have ice inside neptune and uranus that is under such pressure and temperature that it actually acts a bit like a metal and can form the magnetosphere around these planets so it could very well be that you get a magnetosphere forming around this planet of water but you know if it's pure water you're not going to have any of the really heavier elements you're really just going to have oxygen and hydrogen and that's that and so it would be tricky to have any kind of life form you need some heavier elements some kind of rocky core carbon whatever this is like a total tangent but there's been a lot of thinking about like how habitable would be a world that has a very thick layer of water like one that is maybe hundreds of kilometers thick before you get to the rocky core or the rocky layers down below and there's arguments kind of going back and forth on whether or not you could have life at all because it's just so far removed from the nutrients to where the sunlight is providing energy but would it not evaporate and that really just depends on how far away it is from a star and so if it's really far away from a star say out at the orbit of saturn then no it won't evaporate just like enceladus doesn't evaporate but if you moved it into the inner solar system put it at say the orbit of earth then yeah it would evaporate the sunlight would be constantly beating it up would be sublimating the water off the surface the ice you'd be blowing it away off into space and it would get slowly smaller and smaller i'm not sure like how quickly it would happen but it definitely wouldn't last forever if it was close to a star pole took if we're alone in the universe is it our duty to send life to other star systems before we go extinct this is an idea that i think a lot about and and honestly this is this is one of the ideas that got me so enthusiastic about space exploration and astronomy when i started uh universe today about 21 years ago um and just this idea that you know what if we're alone in the universe like obviously everyone always says like there's no way we're alone in the universe but what if we are what if we're the only place that life is formed does life make the universe better i mean obviously it has its problems has its faults but i think most people would agree that that having life in the universe is better than having not life that pandas are better than boulders that um whales are better than silt so i just feel like having life in the universe makes it better and so then if we are alone and we're the first technological civilization to reach this point then do we have a moral obligation to help life spread across the universe i think we do you know as i mentioned a couple of episodes ago that we've only got say 500 million years before the sun boils the oceans off of planet earth and maybe we've gone extinct but maybe we used up all the metals and the oil and all of the easy access to various minerals and stuff and so then when the dolphins rise they don't have anything to work with and then when the octopuses rise they don't have anything to work with and so nobody can achieve a space-faring civilization it's up to us and if i sort of think about like the biggest priorities like what should we be doing we should be searching for life to just find out if we are alone in the universe and amazingly that is a scientific question that we could answer because the larger a sphere of the milky way that we explore and examine and don't find any evidence of life then the less chance there is of life being common in the universe right if we examine a sphere of the milky way that's a thousand light years across and we've got such powerful telescopes that we don't see any bio signatures on any of the planets orbiting any of those stars then that's a pretty good sample of the milky way and it tells us that life is either extremely uncommon or we're the only ones and so the priority is to search for life and if we continue to not find life then the second priority is to make sure that we don't go extinct and i would say the highest priority of that is to take better care of earth because we are ruining the best place in the universe and then once we've made sure that we're taking good care of earth then let's do a good job of spreading out across the solar system and maybe we do those two things you know we can we can walk into gum let's take good care of earth and let's explore the solar system and get all of our eggs out of this basket and let's figure out a way to potentially move to other star systems so yeah i i personally think it is our duty that that the universe is made better with life and let's share the the bounty that that has happened here on earth jeremy harris could an advanced future civilization cheat the heat death of the universe by creating energy from tidal friction for example moving moons into close orbits around planets like iowa and jupiter and then harvesting the energy created would it be theoretically possible to do this even with objects that had already cooled to the background temperature of the universe first you can never treat the heat death of the universe in the end the heat death of the universe will win um but you can of course try to prolong your existence in the heat death of the universe and so the thing that you're describing like you know we know that say io is heated to the point that it's got the most volcanoes in the solar system because of these tidal interactions that are happening between io and jupiter and jupiter is flexing io back and forth and kind of squeezing and squishing it and warming it up same thing is happening with europa and yeah absolutely if you had a giant planet floating in space and you had a series of moons orbiting around it then they would interact with each other and with the planet and it would cause tidal flexing and it would warm them up but that would just be a delaying tactic the price you pay for this tidal flexing is that you lose orbital momentum you lose all the variation and so what's going to happen is eventually the planet and the moons are going to be in lockstep with each other they're going to be orbiting around in exactly the same way lined up in a certain kind of resonance they'll be tidally locked to the planet and there will be no more room for tidal interactions and then everything will cool down to the background temperature of the universe so every single idea that you can ever have to cheat the heat death of the universe is getting up with the same answers which is you can't cheat the heat depth of the universe but with energy conservation you can imagine really clever ways you're feeding a black hole sips of energy you're dismantling stars and then creating fusion based on the hydrogen that you're pulling out of them that's way more efficient than a star just going crazy burning through all its hydrogen and then exploding as a supernova so there's plenty of ways that you know once we get to an advanced enough level of technology we can lengthen out the amount of time it's going to take before we run out of energy but in the end we have to run out of energy subnet mask hey fraser of all the planetary bodies that we know of apart from earth which offers the longest survivability for a human wearing nothing but lots of layers a really warm coat and a gas mask the way you described that question there's really only one place that you could exist for a long time and that would be on the surface of titan titan of course has an atmosphere that's about one and a half times as thick as the earth's atmosphere it has very cold temperatures but it has that atmospheric pressure and so you don't need to have a spacesuit you just need to have a really warm coat but the atmosphere is not breathable and so you would need some kind of breathing apparatus as well i mean essentially you're gonna need to have a coat that is so complete with such heaters that it'll feel like a spacesuit but it won't need to be pressurized against your body in the same way that a spacesuit does so that's pretty much the only place that you could walk around outside without a pure spacesuit but there's a couple of other places so the other idea of course is that you could be in the cloud tops of venus you'd be about 50 kilometers above the surface of venus and at that point the temperature of the planet and the pressure are roughly the same as the earth so once again you could stand outside on your cloud city on venus in your short sleeves or probably a coat and again a breathing apparatus because the atmosphere is carbon dioxide and you would be fine and then there's places that you could go that it would be a lot quicker like you could swim in the ocean of enceladus or europa briefly and you would need to have a spacesuit because you'd be in water you just need like a scuba diving suit as well as some kind of oxygen mask so you literally could take your scuba diving suit gear up to go for a dive here on earth but you could go to the ocean of enceladus you could drop in the water there and swim around and it would be kind of the same you could survive briefly falling into the atmosphere of say uranus or neptune until the the pressures get too great but but that's about it so so but there are a few places you can go uh let me know how it works out kim baron what would be involved in decommissioning the iss or hubble since they're kind of large right when hubble and the international space station run to the end of their lifetime and the plans are okay these are no longer functional hubble is dead it's time to deal with it the international space station is just it's no longer habitable for astronauts it's time to remove it then they will be deorbited and what will happen is essentially a retro rocket will fire there's an attachment on the hubble space telescope so it's ready to have something dock with it and deorbited and with the international space station they would probably just either fire the thrusters on the space station or dock say a dragon capsule and have it fire the thrusters and this happens from time to time and actually there's a place in the pacific ocean where all of these spacecraft go if they can do it sort of this big chunk of the ocean where there's no islands there's no population the chances of anybody having any problems are very low and they will deorbit it through the atmosphere and crash it into the ocean and with these larger objects say the size of the space station the size of hubble etc lots of this will survive the entire atmospheric reentry and plunge into the ocean and if you don't do that then some of these larger satellites it's just random where they crash into the earth so you know in most cases when countries are being responsible they build in the de-orbiting capabilities so that they can crash into the great pacific graveyard at the end of their lives and for some countries which have not been responsible they have crashed them into canada and australia and sometimes they get lucky or mostly they get lucky and they crash them into the ocean but uh you know do you really want to be responsible for having your satellite crash into a population so so most of the time people set up deorbiting capability on the space station or satellite more questions in a second but first like to thank our patrons corey chapman ben galvin dennis van linde bill hamilton choo choo and the rest of our 781 patrons for their generous support want our videos early with no ads join our community at patreon.com universetoday trey harmon hey fraser could the hypothesized planet nine be explained by our son actually having a dim binary sibling that we haven't yet identified just a crazy thought maybe a distant brown dwarf that's a good question it's not a crazy thought and in fact nasa launched a mission called wise that its primary job was to search for brown dwarfs in the vicinity of the sun the solar system and using wise they were able to essentially rule out any objects the size of jupiter or saturn in the outer solar system within about 50 000 astronomical units of the sun so we know for sure that there is not a satisfied jupiter-sized brown dwarf-sized object out in the outer solar system that leaves a neptune-sized object that is closer and that's what planet nine if it is out there has to be or smaller kernel zack if you don't sufficiently tackle the climate emergency how will space exploration be affected in the short and long term i like that term climate emergency um climate apocalypse like like i don't like climate change or global warming they just sound too tame so so i i've been i've been mulling around different catastrophic terms to use for this just to just to really kind of hammered home um so how would space exploration be affected by climate change well obviously the kennedy space center is built on low-lying swamp in florida which would be inundated by the oceans uh you know a lot of the space centers are built near oceans so you can imagine that that would be an issue but i think larger you're just dealing with the economic implications of having to pour money into building dams building dikes dealing with water dealing with drought dealing with repopulating people that are having to evacuate various regions like it's just it's like a war like when you have a war all you're focused on is basic survival and it's only once you've wrapped it up you can actually start to get back into a growth stage of your economy and i think it's gonna feel a bit like a war in the coming decades and and that just means that concentration is going to be off things like space exploration and so you know that's the worst case scenario the best case scenario of course is that the world's nations decide to agree on the various summits that they've done and they draw down their greenhouse gases and meet the 1.5 degrees celsius climate targets and and the climate of the earth is not too dramatically changed leading to various repercussions and then we don't worry about it so it's just kind of depends on how bad it is like one of the great things about space exploration and just like this kind of work is that it teaches us a lot about the earth i mean think about all of the rockets and satellites that are doing earth observation i mean we wouldn't know the state that we're in without this space technology but also just like all of the research that's happening with astronauts trying to keep astronauts alive in a closed environment i loved the biosphere 2 experiment like i know a lot of people kind of laughed about it but just this idea of attempting to close up an environment and then figure out where it breaks where it runs out what do we not understand about how the environment works it's incredible it's so important i mean literally if we try to build a space station we would need to learn all of that knowledge why not just do it here on earth uh yeah i know i'm kind of rambling um climate emergency depends on how bad it's going to be space exploration will teach us a ton about about the climate about the earth about how to live in a more uh environmentally protective way and i i hope we don't have any sort of bumps in the road along this path of space exploration tp seeker was it a type of mold bacteria found on the outside of the iss and would it be considered an alien life form there was this rumor going around a couple of years ago that that russian cosmonauts had found some kind of bacteria living on the outside of the international space station and i think it was debunked i haven't really sort of been keeping track of it but that said there have been actual experiments and i've done a video or two on these there's been experiments that have been flown to the international space station where they took like the hardiest life forms of earth opened up the doors and expose these life forms to space for years the hot cold temperatures the vacuum of space the dryness of space all of the radiation from space and then they closed it up and brought these life forms back to earth and some of them didn't do so great and others were able to survive and even thrive so it shows that we have life forms on earth that are perfectly able to fly to space and beyond say the outside of the international space station and still be fine they wouldn't grow but they could be in a state of hibernation and then grow later if they were able to make it back down to earth so you could imagine like we were talking about earlier in this episode right that you've got you know some bacteria has made it to the outside of the international space station and then the international space station crashes back down to earth in 10 years when it's deorbited and the life forms on the outside they reach the ocean again they're like time to get back to work so life finds a way dhr 18 if we discover an oort cloud or kuiper belt in another star system do we use those names or is there a more generic name i think they will be called i mean we've we've reported on the discovery of kuiper belts in other star systems so this has already happened and so you'll see like a belt of icy material or a vast ring of icy material but there isn't a generic name for these they call them other kuiper belts or other or clouds it's funny it's like when you think about other planets exoplanets other star systems the solar system like clearly at this point people will need to sit down and figure out a way to nicely genericize every term in astronomy that we think about that's here in the solar system that these things will exist in other places but yeah i can imagine like you know in the far far future explorers have moved to this other star system and they think about their kuiper belt they will call it their kuiper belt i mean we didn't even know there were other planets like when we think about the earth right the earth is just the ground and it wasn't until we figured out that there were other planets that they weren't just stars in the sky but they were actually worlds like the earth or the moon right the moon is the best example right what do we call you know the moon so maybe maybe what we do with on universe today is we capitalize the moon but then we uncapitalize other moons we capitalize the universe we uncapitalize other universes and so maybe we would we would have lower capital kuiper belt in other star systems grammatically mayor's 12. hey fraser with the mass and dark matter does our galaxy have an escape velocity yeah the milky way does have an escape velocity so let's just talk about the earth so if you want to try to to get into orbit around the earth you need to be going about eight kilometers a second the earth is orbiting around the sun at about 30 kilometers per second if you're already off the earth you're already in orbit and you're using the earth's momentum orbital velocity around the sun they need to go about another 16 kilometers per second to escape the gravity of the solar system so the earth has an escape velocity the solar system has an escape velocity the milky way is just an object with a lot of gravity so it has an escape velocity and the escape velocity of the milky way is about 550 kilometers per second which is a lot it's very fast um and so you might be surprised to hear there actually are objects which have been given that level of an escape velocity astronomers have used gaia and other missions to detect objects that are moving on a trajectory through the milky way at an escape velocity so the question is how like how do you get a star that's moving at this kind of speed and there's two scenarios that have been devised one is you have a supernova so you've got two stars orbiting around each other and one of them explodes as a supernova and vaporizes and now suddenly you've got this other star which was sort of wheeling around in this gravitational hold now is like you've had a sling and you just let the rock go and it just heads off in this new velocity but the other way is some kind of close call with the supermassive black hole at the heart of the milky way and you can imagine some kind of three-body interaction where a star gets really really close to the black hole interacts with another star and something gets kicked out on this incredible velocity but yeah there are like multiple objects that have been discovered so far that are on their way out of the milky way and they're never coming back samara hash would you rather have earth as a nature preserve or make many large o'neill cylinders as nature preserves why choose i mean i think that life is better with nature being preserved like people live in cities i mean maybe there's a few people that just love the glass and steel and concrete and driving beeping cars and ambulances and fire trucks and all the noises and the pollution and all that but my guess is people live in cities because they have to because that's where the jobs are you put up with it yeah there's all kinds of cool cultural things that happen in cities but life is made better with nature with access to trees and oceans and rivers and animals and wildlife and all that kind of stuff so i think that the hope for space exploration is that we can push a lot of the polluting heavy industry off of earth and out into space and then we can try to let earth just become the best place for life including human beings but hopefully we can have a smaller footprint on the planet and then just we just pollute the space who cares right it's just rocks and starlight and you know lots of space out in space um but then like would o'neill cylinders make nature no i mean like the technology that's going to be required to keep a biosphere going in orbit you're gonna have to deal with the temperature with the pressure with the radiation artificial gravity energy you're gonna have all kinds of machines that are keeping everything going all the time so it's gonna be incredibly difficult like just like not dying in space is an incredible accomplishment now who knows like in the future hundreds of years from now our technology would be so good that we trivialize living in space and then maybe we can perform some interesting experiments we can have places that are like the best savannah or the best desert or whatever out in space and try to preserve the various wildlife that we have here on earth because over time earth will try to make everything go extinct right 99 of all species that have ever lived have gone extinct and earth is just going to keep that up so maybe we will sort of start preserving life forms off earth but that's going to take a long time all right those were the questions this week that was a lot of fun as always i do these shows every monday 5 p.m pacific time so if you want come hang out ask your questions live i would be glad to have you if you want a single comprehensive resource for space news you'll want to subscribe to my weekly email newsletter every friday i send out a magazine of space news with dozens of stories pictures brief highlights and links you can find out more go to universetoday.com newsletter to sign up it's totally free 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Channel: Fraser Cain

Views: 15,434

Keywords: universe today, fraser cain, space, astronomy

Id: cCIxAifCRRM

Length: 27min 14sec (1634 seconds)

Published: Tue Nov 09 2021