Q&A 155: Could We Build a Base on Mercury? And More...

hey everyone welcome to the question show your questions my answers as always wherever you are across my channel if a question pops in your brain just write it down i will gather them up and i will answer them here uh in case you're wondering we've got a bunch of really great interviews that i've had a chance to do over the last couple of weeks so check those out uh and of course the weekly space hangout and astronomy cast are coming very soon so stay tuned probably in the next couple of weeks we'll start doing those shows again as well alright let's get into the questions canon lucas hey fraser cheers from chile what do you think about the issue of the blue origin and spacex lawsuits all right so for people who aren't familiar with this of course you've got spacex which has been launching the falcon rockets has launched the falcon heavy is working on the starship and has won a bunch of contracts with nasa they of course are the ones who supply some of the cargo to the international space station they have been launching the crew dragon capsule which has been taking astronauts up to the international space station but nasa's working with a whole bunch of providers and one of the future contracts that nasa did was they wanted to have a landing system for the artemis missions instead of building their own lander like they did with the apollo missions they wanted to essentially purchase a lander from some outside agency and they went to a bunch of providers spacex blorgen dynetics i think they're called um and a couple of others and in the end they chose spacex and spacex with a starship and so the plan of course is that spacex is gonna launch a starship into orbit refuel it a bunch of times fly out to the moon it'll orbit around the moon and serve as the lander so when the space launch system arrives with the orion capsule to the lunar gateway the astronauts will get out and then they'll get into a transfer module they'll go to starship they'll land on the surface of the moon and then come back up and nasa choosing starship was a pretty big surprise and partly was because starship came in you know spacex came in at a much lower cost than any of the other providers also it kind of has a ridiculous amount of power on paper compared to uh what the other you know the other ones were very specific like just big enough to get the lander down to the surface and back up again maybe although nasa was a little concerned by some of the math that was involved with the other landing systems but while starship is just this you know is this monster which has tons of power tons of fuel will be able to make multiple journeys down to the surface of the moon and because of its reusable system and because i'm sure spacex was willing to take a bit of a loss and is already planning to go to the moon um they were able to come in at a very low price and so as part of this process to slow down spacex blorgen has sued and they've delivered an enormous document with uh to the government and it sort of snarled up the process and now the government is having to consider this this legal process in fact nasa the nasa chief came out a couple of days ago and just said like blue origin is in every right to sue and i and i i kind of agree with that like obviously um suing to get your way as opposed to competing to get your way is not necessarily the best way to conduct business but it's just business and so you try to use everything that you have at your disposal and if that means lawsuits to because you think that you are truly being treated unfairly by nasa by the people who are choosing then it's you're with well within your rights to be able to do a lawsuit and have a chance for the government officials to look at it another time for legal experts to consider the situation and find out if the case that you're making is legitimate and so you know it shouldn't be surprising that this is happening um and if the spacex case is still really strong if the blue origin case is as weak as as originally what caused them to not win this contract then their case will be thrown out and spacex will continue on but of course you know starship isn't flying to orbit yet it's definitely not in lunar orbit it is definitely not demonstrated that can land on the moon and return back to lunar orbit there's a pile of hurdles of course blue origin doesn't have a rocket that can go to orbit doesn't have a lander that can land on the moon like it's all hypothetical and so now is the time to argue about the stuff into the future and then on the other hand you've got amazon potentially looking to slow down what spacex is doing with starlink and it's the same thing right i don't think anybody anticipated that spacex would charge for with starlink so quickly get so many satellites up in orbit and build out the service before anybody else even had a chance to move of course they've got the first mover advantage they've got the rocket systems they've got all of the the satellites they've got all of the infrastructure to be able to do this if amazon is going to be using blue origin blue origin doesn't have a rocket that flies to orbit yet so it's quite a head start and so if you're trying to compete down the road with what spacex is going to do using the law is just one of the tools at your disposal there's like a saying in the music industry whenever there's a hit along comes a with a writ which sort of says like you know if you're successful just anticipate legal action for to try to slow you down and to try to it's another way to kind of wedge into what you're doing so it doesn't surprise me i think it's totally fair um and as long as it doesn't delay too much the whole process i think it's a you know it's a reasonable course of action for for blue origin to take if they think they're justified it's reasonable for spacex to fight and hopefully in the end the quartz and um and nasa will make the right choice joe why does telescope resolving power scale with size why does a larger telescope allow you to see fainter objects besides light gathering power actual resolution the trick with the telescope is it's all about gathering photons and so the bigger the size of the telescope the more photons you are catching and then you are concentrating them in to your smaller focus that you can then look at with your eyes or with with a camera and you can actually really experience this like if you have like a pair of binoculars you can get binoculars with fairly small lenses and you can look through them and you can see objects that are more highly magnified but they kind of look a little blurry they don't look great they look bigger but they don't look crisper but if you look through a pair of binoculars like both really big lenses like those astronomical binoculars that i use suddenly the thing looks very crisp very clear very close it's almost like you could touch it and so when you look at telescopes it really just is the size of the telescope the reflecting surface the refracting area defines how many photons that you are catching and then you are concentrating them down to be able to see these objects that are that are much fainter so yeah just size number of photons that you can catch darren clark if you interviewed elon musk what direction would you take in your questions and that's a great question i'm you know five years ago i would have loved to have interviewed elon musk i think it would have just been one of the most interesting conversations it would have been super fun but now i don't really care like obviously if him or his pr agency reaches out and they're like hey phrase let's do an interview i'll be like yeah let's do it that'll be super fun but i think that there's too many unsung heroes in the space industry who are worthy of interviews who we're not getting a chance to talk to and and hear from them um for every elon musk you've got gwen shotwell i would way rather have an interview with gwen shotwell over elon musk and then there's thousands of really interesting engineers at spacex epilogen and nasa at the european space agency in japan who are working on very specific technical problems that are really interesting to me and i think it's sort of like you get to a certain point and sort of the general overarching issues that spacex is facing that elon musk is trying to consider are we understand them like we know what his answer is about humans to mars and and the future of rockets and so on and so forth but we don't know some of the more interesting specific technical details and i'm finding as i'm choosing guests to do these interviews with i'm getting really quite excited about scoops my favorite person to interview um and my interview today was was exactly like that we're someone who is very knowledgeable has lots of experience is very enthusiastic very very well spoken and is able to answer and explain very complicated issues but isn't in the public eye isn't worn out by doing a lot of interviews and has some really fresh perspectives on things that we've never heard before and and i feel like that's my job is to is to dig in but i'm sure if i talk to elon musk i would want to just go right into this nitty gritty about a lot of very specific questions that i have about flight hardware about the way the missions would work and and some of the other ideas so so it would be kind of the same you know um in that i would just get in as much detail as i could about uh how things are gonna work how what are some of the challenges they're looking to overcome etc so yeah luke b when the us and china inevitably go to war will the moon be a factor or no i don't like the premise of the question that the us and china will inevitably go to war i i don't think the us and china will inevitably go to war war is bad for business and both china and the us their economies are so mashed together that neither one of them would would ever want to go to war i think china definitely wants to be the leader in technology and science and economic progress and the united states wants to be the leader but i think both groups understand that you don't get to be the leader by going to war that just causes destruction both to obviously human lives and and your economy so i i don't feel like they're going to inevitably go to war i think china and the us are going to use every other trick in the book that they can um to get ahead but i i can't imagine it will be a full-out war and i don't whether full-out wars are going to happen anymore in this modern you know you can have cyber war you can have information more propaganda wars we saw what happened with facebook and social media and things like that so i'm i'm you know that's how wars seem to be fought today but if they did would the moon be a factor no no i mean i mean the moon is not any use militarily i mean it's really far away from earth if you want first strike capability you put your nuclear missiles in orbit and then you have them orbit your enemy countries and then when the war begins you just launch the missiles and they explode within a minute so it doesn't make sense to to try to put some out onto the moon um so no i i can't imagine any military purpose for the moon prince charming do you think that space elevators are feasible i think space elevators are like borderline feasible this is the idea of course of of taking a ribbon of carbon nanotubes attaching it to the surface of the earth reeling it out to beyond geostationary orbit and then you have an elevator that just climbs up this ribbon getting to orbit with a fraction of the complexity danger speed power that it takes for a rocket to do that same journey but there are a pile of downsides to space elevators the biggest one of course is that we don't have the material that could possibly do this i mean we don't know i mean maybe theoretically carbon nanotubes could do it at some point in the far future but you know there's lots of other problems with it the climbing just having a spacecraft that could climb using solar power is actually really difficult and they'll be going to be really underpowered to be able to climb up the tether you can only have one thing going up or down at a time um which is a big problem so i actually think now with the rise of reusable rockets like what spacex is doing with starship the costs of getting cargo into orbit with say something like starship is about the same as what it would be with a space elevator and with starship you could launch thousands of tons a day fully reusably so i actually think the age of the space elevator as a concept is over we're now in the age of the reusable rocket and i think that even the age of the reusable rocket will come to an end when we see the age of the space-based manufacturing resource utilization and manufacturing so right now space is you know just rocks and energy and and everything that's important to us down here on earth but as we launch more and more vehicles in space as we start to build manufacturing and stuff from space which is going to be the cheapest way to do this over the long term then you have less and less need to launch stuff off of the earth and out into space you're going to be able to just move asteroids melt comets pull the off gassing as you vaporize rocks on the moon gather solar power et cetera et cetera et cetera and after a while you'll have chip fabs and 3d manufacturing facilities and greenhouses and all kinds of stuff out in space and so then in the end and i don't think it'll be long like i think we're looking in a couple of decades at the most we'll get to this point where the only thing that goes to space are human beings and a few like really rare kinds of technology that you just can't find out in space that as we start to build these factories and spaces the factories build more factories you get this exponential curve that then everything you need in space is already out there in space and it's there it's the cheapest place to get it so i think space elevators are not really that cost effective compared to reusable rockets and even reusable rockets will not have this long life in our sort of in the future of human space flight we're probably going to shift back to something that is still reusable but it's all about safe safely carrying humans from the surface of the earth to orbit where then there's a completely different set of vehicles that are then moving from planet planet world to world across the solar system matthew jones hello fraser good to see you back sir what is your take on inspiration and do you think the knowledge we gain will be of any different than what we have been gathering on traditional astronauts so if you're not aware spacex is about to do a private flight of four civilian astronauts in about a week from now uh when i'm recording this it might have already happened by the time we released the the video and they're going to fly on a modified crew dragon spacecraft they're going to fly out to a very high orbit higher than any humans have been since the apollo days they're going to orbit around a couple of times and then they're going to return in about three days from when they take off and they're going to land and they will have had an amazing adventure on crew dragon there's some pictures that are going around where they've got this coupler that like sort of like a window that they can then poke their heads out and look around out in space while they're flying away from the earth which is going to be pretty amazing what do i think i mean it's cool i think it's a great first step for space tourism because you're not having to build any space infrastructure they don't have to go to the international space station they don't have to be trained on how to work with all of the complexities of the space station they just have to be trained on crew dragon and the thing that a lot of people don't realize is the crew dragon is actually really big that's about double the internal volume of the apollo capsule so there's plenty of room for four astronauts to be on board crew dragon uh and make this journey over multiple days i think it's gonna be a lot of fun it's gonna be relatively safe i mean we've seen that crew dragon has worked like a charm all the time that it's flown and regular dragon and so this all they know how to do this so i think from as a sort of a first step to how do we get humans to fly in space on a private level this is a great way to approach it are we going to learn anything new not really i mean they're going to perform some experiments but i mean there have been many ways that people have performed experiments in space on the international space station all through the various space shuttle missions et cetera but i mean there's always a backlog of experiments that people would like to try so i'm sure they're going to be busy working but i do like the idea of flying higher and testing out new ideas and so like it's crazy to think that we haven't been beyond low earth orbit in almost 50 years and finally it took spacex and this crew of of private astronauts to make this specific journey and so i do think that that it makes a lot of sense and i'd like to see more of it i'd like to see more complicated tasks go a little higher spend a little longer in space try doing some things that will contribute to the long-term survivability of being in space refuel do a spacewalk like you can see how if they start to tack on additional tasks that it will start to teach some very useful knowledge and skills that we haven't really built in 50 years so there is a path forward but i mean this is really just a an adventure for four lucky people um and not necessarily a meaningful step to human space exploration but you know every step counts i think gyro the hero if we are successful at making a base on the dark side of the moon would it be feasible in the future to make a base on the dark side of mercury all right so i think i need to do a little bit of editing to your question so i mean people talk about the dark side of the moon but there is no such thing as the dark side of the moon every side of the moon is equally illuminated as it goes around the earth it's just that we have the near side of the moon and the far side of the moon sorry pink floyd your astronomy is wrong and the same thing goes with mercury mercury is turning as it is orbiting around the sun and so every part of mercury is illuminated but there are places on the moon which are in eternal shadow if you go to the poles of the moon you've got these craters where the moon is essentially turning with respect to the sun but the sun's rays are never getting to the bottom of these craters and so they're in eternal darkness and you've got mountain peaks that are in eternal sunlight and so you will always have sunlight at the top of various mountains and you always have darkness at the bottom of these craters and you do see the same thing on mercury and so on mercury there will be these mountains that are in eternal sunlight good place to put solar panels and you'll have these places which are in eternal darkness and so in theory you could put a base there and be able to survive in fact there's a plan for a mission to mercury a lander because we've never had a lander for mercury and the idea is to land on mercury and stay on the shadowed side of mercury and so i say that mercury does turn it turns very slowly and so you have dozens of days of complete darkness on mercury so you could land on mercury where it's cooler and survive and then maybe you have like a nuclear thermal generator as your power source and then the rover would crawl around on the dark side of mercury and as mercury slowly turns into the sun and then you've gotten all the signs you're gonna get done and then the then you have dawn and your rover fries in the terrible radiation so so yeah i think um it's a good way to utilize this weird orbit of mercury to get the job done greg rumshite do you think that dark matter is tiny black holes so this is a one of the theories to explain dark matter which is of course this mysterious matter that is spread around the universe it's the vast majority of the matter that's out there up until this point astronomers have like two main ideas one is that it's some kind of particle that doesn't interact with regular matter and so it's producing gravity but we can't see it through electromagnetic radiation the other idea is that it's the force of gravity working in a way that we don't understand at vast distances but at this point the sort of most of the evidence is really leaning on the side that it is some kind of particle like some sort of massive particle that doesn't interact with regular matter doesn't even interact with itself and so one candidate particle that you could use is a black hole a black hole doesn't shine with radiation black holes can collide but in general they have to get very close before they're going to actually collide with each other and so astronomers haven't been able to rule out the idea that they're black holes now you talked about them being tiny black holes in your question but they don't need to be tiny they can be tiny or they could be a thousand times the mass of the sun and anywhere in between there's different versions of counting up the total number of black holes you could have like just a few really heavy black holes or a lot of really light black holes and you would still be able to answer the problem of of dark matter and astronomers haven't been able to rule this idea out but the idea of them being tiny black holes because hawking knew or has worked out that black holes should evaporate over time that any of the black holes smaller than the size of an asteroid of a small asteroid should have evaporated since the beginning of the universe and so you wouldn't be left with these teeny tiny black holes although i mean you know something with say the mass of the moon compressed down would be a very small black hole but that these could be wandering the universe randomly running into planet stars each other and uh and they could answer what dark matter is and so astronomers have actually done some surveys to try to confirm whether or not this is a real thing and the most powerful way to do this is this technique called gravitational microlensing and so what astronomers do is they look at a galaxy like andromeda and they watch the brightness of all the stars of andromeda all at the same time and they're looking for any stars to wink and the winking will happen or any stars just essentially appear out of nowhere and then disappear again and that's because you get these within andromeda you can have all of these stars that are lining up with each other perfectly and when they do the foreground star acts like a lens for the background star but in this case if you get a black hole the black hole could be in the front and the star could be behind the two could line up perfectly and now the black hole acts as a lens for the star that's behind it making the star really bright but there would be no foreground object that you would see and astronomers have actually found some evidence that there are some number of these intermediate mass black holes located in other galaxies so they still can't rule the idea out but you know if you like ask most astronomers they they don't think it's true but they yeah they won't rule it out joe when we look up why does the milky way only cover one side of the sky not both i'm not sure what you mean exactly but but when you look up into the sky and you see the milky way you can pretty much see the milky way all year long from pretty much any part of the earth so here in canada for example i'm in the northern hemisphere i'm located about the 49th parallel and for me the milky way appears as this cut across the sky the heart of the milky way the sagittarius region is seen to the south for me in the summertime so in the summer i can look to the south and i can see where the center of the milky way is but then you still see the bands of the spiral arms on both sides to the east and to the west of the milky way but you can still see the milky way in the winter time as well and so just imagine it right in the summertime you are looking you know where the the earth and the sun are positioned the essentially the sun is located in the outer spiral arms of the milky way from your perspective and so you're on the earth and at night time you're looking towards the core of the milky way and then during the winter time now the sun is located in the middle of the milky way it obscures it from your view you can't see it in daytime the center of the milky way is up but at night time you're looking out through the outer rim of the milky way and you can definitely see it and so you can see the milky way pretty much every clear night it's just that during the summer time it's a lot denser because you're looking into the core of the milky way while in the winter time it's a lot more sparse you're looking out of the milky way but you can still see it the entire year darren clark how do astronomers know how much a star weighs just by observation that is a fantastic question and the truth is that it's very very difficult to know how much a star weighs if you're just looking at one star and so if you're just looking at one star you're kind of guessing based on what the star is made out of how much energy it's producing and sort of what kind of a classification of star that it is you know if you see a red dwarf that's putting out a certain amount of light then you know that it probably has 50 the mass of the sun while a very blue star that's putting out a very hot kind of of light is probably could be two three four times the mass of the sun and in fact just this idea of knowing how much the mass of something is is a really tricky problem when you're looking at something by itself the way you can calculate the mass of an object is when you can see it in some kind of gravitational interaction with some other object out there in space and so if you're seeing say a binary pair of stars that are orbiting around each other by calculating how long it takes for them to orbit around each other that tells you with precision the mass of the two objects this was a calculation that i think newton first came up with and is used all the time and so whenever astronomers are trying to figure out the mass of something out in space they're looking for some orbit that it is going through whether it's got planets going around it whether it's got a moon uh asteroids going around it some way to calculate the motion of multiple objects that's what tells you the mass but if you're looking at something just by itself it's really tricky to do you have to use secondary methods linda williams i'm sure you've answered this before but i've been wondering lately what would space look like to the human naked eye once we have escaped from our local galaxy group dark i mean this is a this is a question that people always love to ask and i have answered this several times and i've even done whole videos about this idea that we are spoiled by what space looks like because we're always looking at pictures of space that have been taken with a camera that is doing a very long exposure so our human meat cameras they are gathering up photons for maximum say 10 seconds and then they're throwing out all the photons and so when you're perfectly knight adjusted and you're looking up in space you're seeing what your eyes can do with a 10 second exposure at best while when you're looking at pictures of of galaxies and nebulae and things like that taken by camera you could be looking at minutes hours days of total exposure time onto whatever medium they're using film or ccd etc and so it's not fair to look at a picture of the orion nebula or look at a picture of andromeda and think boy if i could just get closer then it would look like that with my eyes and in fact this is a mistake that they always make with science fiction the spaceship is cruising besides some nebula and you've got these beautiful nebula features all around them you wouldn't see any of that you would at the very best see a slight fogginess haziness around you and so think about the milky way of course we are trapped inside the milky way when you go out at night and you look up into the sky as we talked about earlier in this episode and you're seeing the milky way you couldn't be closer to the galaxy right it is um you know the center of the milky way is only 26 000 light years away from you and still you have to be on have very dark skies have no light pollution you got to let your eyes adjust and then you can see this kind of milky cloudy band across the sky but you can't make out the stars etc another example of a galaxy that is quite big several times bigger than the moon actually from our perspective is andromeda and yet once again you got to have like very dark skies you've got to be able to know exactly where to look and with your eyes you see this sort of just this little fuzzy cloud in the sky and you're like oh that's andromeda and you can't see any of that detail it's only when you are recording the image for a very long period of time do you actually start to see all of that really delicate structure and so unfortunately for pretty much all of the stuff it you can't make it look better no matter where you go if you get close um if you get to just the perfect perspective it will never look any better than it does from from here on earth now there would be sort of a sweet spot like you could get to say a million kilometers away from andromeda and be directly overhead and you've got your telescope set up and a really nice long exposure photograph that you take that would be perfect but without a camera it's never gonna look good for just your eyes which is really sad but just means like don't go to space i mean don't fly out of the don't fly to other star systems hoping to see nebulae better than you can see them from here on earth amy's cotton flower when will james webb launch oh zing uh we get this question you know i believe i've been answering this question for close to a decade now uh when will james webb launch december 18th 2021 so about six weeks after the original october 31st launch date that we were planning on james webb will launch and i know like you're like oh yeah tell me again fraser you know you're going to pencil this in lightly into your calendar but at this point james webb is bundled up it's being put on its cargo vessel it's going to be sailed down to the launch facility all of the parts of the rocket have started to arrive at the launch facility in karu french guiana so the most of the big uncertainties are all like if there's a problem with james webb it's it up into a shipping container and that problem is is in there somewhere and no one's going to be able to find it out they've done as many tests as they can do they've jumped through every single hoop and hurdle and so now it's just a matter of hoping that all of that engineering work that they did is going to work out there were some problems with the ariane 5 launcher uh but now arion feels pretty confident they've gotten to the bottom of this they've solved those problems so james webb is done on its way down to south america the area on rocket the problems have been worked out the parts are coming together so i feel pretty confident that we're now looking at a fairly solid date for james when launching but i mean like it's hilarious now how long things take so who knows and of course when it's actually stacked up on the like would you would you press the button to launch james webb or would you say like oh just like one more test let's just try one more let's just check this oh the weather's a little well it's a little dicey i i think i want to hold off another week just to be safe so who knows how many more delays once it's actually because they're gonna i'm sure they're gonna wait for absolutely perfect weather they're not gonna take any chances james webb must fly there is 10 billion dollars of money and mind power and scientist expectations bundled up into that rocket into that mission and so it's got to be successful and just like like here we are now in september but i'm just imagining what it's going to be like when we're in december after it launches even and then it's going to spend a month unfolding and every single actuator's got to work perfectly like i'm not going to get any sleep it's going to be terrifying gitmo holiday i have a question about balloons would it be possible to use a hot air balloon on mars by heating up carbon dioxide and the density difference would make it float yes a hot air balloon would work really well on mars in fact there have been several missions proposed to do exactly what you're talking about now the challenge comes that during the night on mars temperatures can get very cold 100 degrees below zero while during the daytime it can get reasonably warm you can have the temperatures be say even up to 10 degrees centigrade so the idea that was proposed is that you would have a balloon that would be fully inflated and would rise during the daytime on mars and they would have this cable below and an instrument package that would be riding below it and then during the daytime it would the it would inflate and it would rise up off the ground and it would float on the air currents and then at night time it would sink back down and then it would just sort of rest you sort of imagine a partially deflated helium balloon that you've had from a party two weeks ago and then the string would be sort of hanging the cable the instrument package would be lying on the surface of mars waiting for daytime again and the day would come and then that would warm up the temperature that would increase the volume of the balloon it would rise up again it would fly again and so it's a pretty great idea of course you can imagine some of the technical challenges like having your instrument package have to slide across the martian landscape every night as it's as it's lowering back down and so i think you know when we look at the incredible success of ingenuity that's the way mars is going to be explored by the air i mean it's been such an incredible success and you can imagine a future mission going with like an aircraft carrier bringing along dozens of these helicopters just dropping them out into mars at various points and then they all land and then they all just wait collecting their sunlight and they lift up and they fly around and then they land and they gather more sunlight and they just go they're inexpensive they are clearly very um you know long lasting and so i think it's a great idea but if you want like a heavier instrument payload the the balloon idea actually is a pretty good one and we did an episode about that a couple of years ago but um but yeah i think it's a i think it's a terrific idea i'd love to see someone try it a balloon on venus obviously is sort of the right place to take a balloon mission and hopefully we'll see something using similar techniques something that can change the volume of the balloon to go higher and lower in the altitude of the atmosphere but i do love the idea all right so those were the questions this week thank you everybody for uh jumping in the chat on the live stream asking your questions as well as all the people who are asking questions in the comments i love to read through them i love to answer them so we'll be back next week with more questions thanks 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 about the story and links you can find out more go to universetoday.com newsletter to sign up it's totally free and did you know that all of my videos are also available in a handy audio podcast format so that you can have the latest episodes as well as special bonus material like interviews with me show up on your audio device go to university.com audio or search for universe today on itunes spotify or wherever you get your podcasts and i'll put a link in the show notes thanks as always to all the moderators and a special thanks to chad weber and nancy graziano

Channel: Fraser Cain

Views: 20,683

Keywords: universe today, fraser cain, space, astronomy

Id: wLY-0KIImr4

Length: 37min 11sec (2231 seconds)

Published: Tue Sep 28 2021