Q&A 133 What s Causing the Expansion of the Universe And More

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So Hello, and welcome to my questions and  answers Show. I'm Fraser Cain, publisher of   Universe Today. And this is your chance to ask me  questions about space and astronomy. So if you're   watching this live, go ahead, post your questions  in the live chat. If you're watching this after   you can post questions, you can send me email,  you can post on the YouTube comments, you can   post in Patreon. Set up a Discord server, you  could post there, so there'll be lots of places   for you to send us questions. So Joe asks, even  though we don't know what caused the Big Bang,  

did dark energy caused the Big Bang, and  it is accelerating the universe outwards,   because there is less gravity once they're farther  apart, what's causing the universe to expand is   two parts. Whatever caused the Big Bang, and  again, like, we don't know what caused the Big   Bang, what is the underlying event that brought  all of the matter and energy into existence.   And then what caused all of that, to expand  outward at this incredibly rapid rate. We   don't know what the underlying source of  that was. But we do know that it happened.   And we also know that essentially, the expansion  of the universe is driven by two things. It's   driven by essentially the leftover momentum of  whatever was that original expanding event. So  

the universe, the Big Bang happened, and it's like  kick a bang, that is causing this expansion. But   again, it's not an explosion, it's an expansion  in all places. It's going on, and left to its own   devices, the universe would keep on coasting.  It's kind of like I don't know, like you   roll of car, you drive a car really fast. And  then you take your foot off the accelerator,  

and the car just rolls and it slows down and  it slows down, it slows down. And eventually it   comes to a halt. And, and that's what would happen  to the universe. This is one of the big questions   that astronomers asked themselves 20, ish 25  years ago, was, you know, based on this original   expansion, and then you've got the mutual gravity  of all these galaxies, are they going to sort of   expand away from each other forever, or will the  mutual gravity eventually slow them all to a halt,   and then they'll all start kind of crunching down  into bigger and bigger clusters until eventually,   you've essentially got the entire observable  universe falling in to one spot. And,   and so astronomers went and and they did this  survey, and they were looking at type one, a   supernova, which are sort of considered  the standard candle, the way to determine   sort of a standard distance to everything in  the universe. And the big surprise, of course,   was not only could they not measure that the  universe was slowing to a halt in its expansion.   But in fact, it was speeding up in its expansion,  it was accelerating. And this is completely  

not what anybody's expecting. And sort of the, you  know, the analogy that I was like to give is like,   you take a ball, you throw the ball up into the  air, you expect the balls gonna come back down   into your hand, right? And then that tells  you and that was sort of one possibility.   And the other possibilities of you throw the  ball up into the air or go off into space,   and it would sort of fly away from play slowing  down, eventually, it would get, you know, close   to a halt exactly at the point where it, you know,  wasn't going to fall back towards the earth and it   wasn't going to fly away. Or you could throw it  so hard that it would just never come back to the   earth. And what they found is you throw the ball  and the ball immediately just starts accelerating   away from your hand off into the universe. And  so the universe is expanding and accelerating,   and this is dark energy. And so the  expansion of the universe is driven by  

the momentum leftover from the Big Bang, as  well as the, the accelerating force of the   dark energy. And over time, the dark energy is  going to be the thing that's completely dominant,   and is just pushing everything in the universe  away from everything else, faster and faster   and faster. Live vibe lasers fringer. Can  you discuss the size difference between the   observable universe and the unobservable universe  that has crossed the cosmological horizon,   I've heard the unobservable is 10 to the power  of 22, x in size. So the observable universe  

is the universe that you could observe,  and you have an observable universe   and I have an observable universe. They're  different. My observable universe, you know,   if if I'm standing to the left of you, then my  observable universe is like one light meter away   farther in one direction. So I'm seeing a little  more in my direction, and you're seeing a little   more of the observable universe. So so when we  imagine this, the sphere around us have, you know,  

46 billion light years in all directions, that  is the observable universe, it's just that that   everything in that region has been able to give  off light that has traveled all the way to your   eyeballs for you to be To detect and of course,  as we look out into the universe, we see things.   As we're seeing them farther and farther away,  we're seeing them earlier and earlier in time.   And of course, the analogy that with that,  though, is like to use is imagine you're,   you're standing in a room, and really  close to you've got a bunch of old people,   and then middle aged people a little farther  away, and then really far away, it's just   babies. And then there's nothing, because that  is what that's what it would look like to look   backwards in time as you're looking farther  away. And so you're always seeing this, this   really weird thing of the universe, you're seeing  backwards in time, as you're seeing further away.   And, of course, we don't know how big the  actual universe is, the observable universe   is just a tiny little segment of it. Now,  one possibility is the the entire universe  

is infinite goes on forever. And so the,  the observable universe that we can see is,   I don't know, one, one divided by infinity,  of the actual universe that is out there,   infinity divided by one anyway, the other  possibilities of the universe is finite. And   so it could be, as you say, you know, it is at  least much, much, much, much bigger, like 1000s,   millions, billions of times bigger. And the  way astronomers figure this out is essentially,  

they're able to calculate the curvature of the  universe. So they're able to essentially measure   these gigantic triangles in space, they look  at the cosmic microwave background radiation,   and they measure gigantic triangles crossed huge  chunks of the universe. And then when they look   at these, these triangles are trying to measure  some kind of spatial curvature that's going on.   They are almost tell you, what is the entire size  of the universe itself. If If yours just went on,  

when would it wrap? And right now, from what  they can tell the universe, the real universe   is so big, they can't measure the wrap, which is  why then they think, well, the universe is either   finite, but so big that we can't measure it, or  it's infinite, and the jury's still out better   and better measurements over time, we'll either  figure out how big the universe actually is,   or push that minimum size to bigger  and bigger amounts until eventually,   everyone's just going to say, okay, fine, it's  infinite. So we don't really know. I like just,   I can do a whole episode where we just don't know  the answer to anything perfect. Jeff Wilkie asks,   Do more people watch your videos on YouTube,  or listen to the same podcasts, I get about   about 150,000 downloads a week on my podcast.  And that's all of the episodes that we do. But  

typically, you know, we're releasing about eight  episodes a month, 350,000 downloads a month.   So it works out to about 10 12,000 listens  for each new podcast, and then a few more   for all of the old episodes that people are  discovering. So So I would say that we. And   then on YouTube, I get about, say about 10 to  15,000 people watching the videos. So the numbers  

are kind of the same, actually, we get a lot less  people watching the YouTube channel these days,   mostly because I'm producing a lot less content  for the YouTube channel, a lot less of the   original scripted episodes, and a lot more of  the quality, sort of the questions and answers   and the interviews. And that is a preference for  me. And so I think I'll spend some time explaining   that. Because I know a lot of people were  wondering, like, how can we don't make those guide   to space videos so much anymore. And the reason  is, because I don't think I'm very good at it.   The more you learn, the more you realize that  you don't really know anything. And what I've   found is interviewing experts in various fields,  be it astronomers, astronauts, physicists, etc.  

I find that it's very useful  to go right to the source   to be able to just talk to the people and say,  hey, what, you know, how does this work? How does   that work? How does this work and to be able to  sort of piece together a picture and it makes for   content that is a lot more accurate, as opposed  to me attempting to translate it from what I   sort of think I understand trying to  synthesize information. And so I found   when I sort of look back at the older  guide to space stuff, I find that   that although they were entertaining, and although  I think people thought I did a pretty good job.   To me, it felt like I need to get more information  directly from the source. And so I think   that's sort of where my mind is at. And and  I'm sort of bringing you along Along with  

me. So I've found a lot of the the interviews,  long form interviews that I've been doing to be   really fascinating, really interesting stuff about  pushing the cutting edge of space exploration and,   and astronomy and people working on robotics  and engineering and things like that. So,   so I think that's where we're  going to go a lot more. So I think  

that's my opinion right now. But anyway,  that's, that's why I'm trying to some   people have been asking me why I'm doing  the guide space. And it's okay, just,   I'm not into it. I'm really into interviewing  people. So that's how I feel. So physics, police   asks, Will dogs have fun running in lunar  gravity? First, I want to thank physics   police for being the actual physics police on this  channel, and with me, we've had a very vigorous   interaction over the years,  but I always appreciate your,   your feedback and your attempts to raise  my quality and capabilities. So thank you.   Well, dogs have fun running in lunar gravity.  And we talked about this a bit in the past that,   that Mars gravity it at like 40% 35% is, is  probably good enough for humans to be able   to walk around and, and not have a hard time. But  when you get down to the lunar gravity, like 15%,  

we've seen that the astronauts had a really hard  time, being able to walk around on the moon,   they were falling over all the time, they weren't  hurting themselves, but there's a potential to   hurt themselves. So actually think that in the  beginning, when you go to the moon on your lunar   holiday, you're gonna have to completely relearn  how to walk on the moon is going to take a while   because there is some gravity, but not a lot of  gravity. And it has all kinds of repercussions,   like the amount of friction that you have,  when your foot is touching the ground,   you have less friction, and so you'll fall a  lot more easily. Something that would have been   no problem walking around in socks, you're gonna  have a hard time walking around, you're gonna need   special kind of shoes. And so if you think of  like a dog, like of course, the dog will have  

fun doing anything. But, um, but I think in the  beginning, they're gonna have a really hard time.   Have you ever gotten a cat and you live in a  place with a carpet, your cat should burn round,   your dog is just burning around the house really  fast, they're having a great time. And then you   move to a place with hardwood floors, and  that the cat or dog just doesn't know what   to do right there. They, they they slip out as  they go around corners, they completely lose it.   And it's gonna be like that. It's gonna be  really hard. I'll bet you there won't be such  

a thing as smooth floors on the moon, there will  always be everything will be a non slip surface,   no matter what it is that you're walking on. But  of course, like because you're going to have one   sixth gravity won't hurt the same. So anyway, it's  gonna be it's gonna be funny. I like it. 25 in   30 s. Why aren't we looking further past Pluto,  or taking its time law? I'm assuming what you  

mean is why aren't we looking past Pluto in the  solar system? And of course, we are. Astronomers   have discovered all kinds of things in the outer  solar system beyond the orbit of Pluto. In fact,   it was the discovery of Eris, which is a dwarf  planet, it's roughly the size of Pluto that has   its own moon, just no meah that caused the whole  Pluto crisis in the first place. Astronomers   Mike Pluto killer Brown was looking in the  Kuiper Belt for other Kuiper Belt Objects.   And he found an object that was roughly  the same size as Pluto, we've now learned   that that Eris is a little smaller, but it's  much farther away from the Sun than Pluto is,   but it's roughly the same size. And so then the  problem is you found an object that's the same  

size as Pluto, does it get to be a planet  to don't have a 12th planet? And in fact,   what about all the other ones, homea and Maki,  Maki, and series and all these other ones that   are roughly the same size too. Don't they  get to be planets. And so back in like 2003   1000 5005, the International Astronomical Union  came and had the big vote where they're like,   what are we going to do about this? And they  decided that Pluto was no longer a planet because   we are finding all these objects. And since then,  astronomers found many more. There's the most   farthest one on I forget what it's called.  It's got a really hilarious name like, ah,  

far, far out. Yeah, I think it's called, there's  one called far out, and one called far far out.   And of course, astronomers have discovered Sedna,  which is an object that at its farthest point,   I think goes like 600 astronomical units away  farther away than Pluto. And we're right around   the corner from the next great observatory  that's going to be coming online. The viewer   Rubin observatory previously known as the Large  Synoptic Survey Teller, Let's go. And this one   is going to be the machine that finds a  zillion Kuiper Belt Objects and could be   the telescope that finds Planet Nine, which  is going to be the theorized much larger,   like Neptune sized planet that's in the outer  solar system way beyond the orbit of Pluto. So  

the limit of what we can find really just depends  on the power of the current telescopes. And then   following on with the Vera Rubin is going to  be the Extremely Large Telescope. This is a   39 meter telescope, it's going to be capable  of I feel like I talk about this every week,   but it's gonna be capable of viewing Earth sized  worlds directly orbiting other sun like stars.  

And it will definitely be capable of taking a good  look at any planets, any other objects that your   Rubin finds in the outer solar system. So as the  telescopes get better, our ability to look farther   and farther out into the solar system gets better  as well. arjona asks, what interesting forms of   motion would be good for exploring the moon's  latitudes? That is a great question, because   we've mentioned in previous videos that, that the  latitudes on the surface of the moon are, are one   of the best places for us to get like, if you want  to go to the moon, you want to get protection from   space, the lava tubes are great, once you're in  the lava tube, you're completely protected by the   radiation, you've got better temperature control,  you've got potentially a place you can set up   you've got micrometeorite protection, they're  really good places to go. And they give you a view   of the history of the surface of the moon, you've  got all of these samples, all this material,   you've even got, like lunar dust that it you  know, if it's got like some kind of, of skylight   on the top of it, then dust has been falling  into this hole for a long time and stratifying   in layers that you can quite easily sort of look  through and see the history, not only of the moon,   of the of the even of the earth, of the solar  system of the universe is thought to be written in   lunar dust. So these lava tubes are great, but the  challenge is that they're dark. And so you can't   take solar panels up to the surface of the moon,  they are also potentially very rough. If you ever  

walked in a lava tube, they are, you know, they're  not easy for wheeled vehicle to roll around,   they're probably boulder filled, they probably got  all kinds of material and debris. So some really   interesting ideas have been proposed. There  have been hoppers. So imagine some kind of,   you know, multi legged creature that can sort  of flop around and low gravity with style,   and be able to move itself around in this low  gravity environment. There's been snake bots   proposed, which would be like, like, they look  like snakes that would be able to crawl down into   small crevices and be able to search and explore.  So I actually think it's going to be a pretty big   challenge to, to come up with a rover or a flying  bot, something that is capable of, of being able   to maintain power in the dark, and the cold,  extreme temperature while you're on the moon,   but also be able to search these very bizarre  terrain. But if they can be if it can be figured  

out, then it's one of the best places for for  robotic missions to go. So I'm pretty excited   about the idea, we'll keep you posted. One thing  that's kind of interesting is the Chinese with   their upcoming mission, they've got a mission  that's going to an asteroid called Dong ha,   in 2025 26. And it's going to be sending a whole  bunch of stuff they're going to be sending in an   orbiter, they're going to be sending a lander, and  they're also going to send a bunch of mini probes   are going to be going with it that will try to  explore the surface both from the ground but also   to try to kind of fly around. And so I'm trying  to keep an idea on what they're doing with that   because I can imagine, I mean, it's a very  low gravity environments, you don't need a   lot of propellant. But I can imagine a situation  where you've got a, like a spacecraft that is   using propellant to hop around on the moon in  these craters to be able to explore but but again,   it's fascinating, it's a great environment,  we should definitely explore for the other   possibilities that you just sort of have a  solar panel up at the top of the skylight and   then you reel down your power cable that can  then I don't like think about like the divers   back in the 1800s. Right. Except in this  case, it's electricity not not air anyway,  

it's it's gonna be a big challenge. And there's  a lot of great projects, people working on it.   I'll get some of them and interview them  for you. Eric one asks, whatever happened   to the overwhelmingly large telescope, so I talked  about the Extremely Large Telescope. This is the  

39 meter telescope that's being built by the  European Southern Observatory. It's the follow   on telescope to the Very Large Telescope. I know  I know make jokes about the name, but when they   were designing the Extremely Large Telescope,  they also design This idea of the overwhelmingly   large telescope, and it was going to be a  100 meter telescope. And the gist of it was   that it would essentially be the largest possible  telescope, you could have on Earth, a 100 meter   primary mirror, it would be incredible. And the  problem was, it was going to be too expensive. And  

so the European Southern Observatory decided they  were going to build an extremely large telescope,   which was only going to cost $1.3 billion.  In its most recent price, now, they went   from 1.1 5 billion to 1.3 billion, but not in the  bad way. Like in the way they're where they said,   let's add a bunch more functionality and  capability to the observatory, which is great.   By the way, they have a new website to  see if you want to go and check it out,   do a search for the Extremely Large Telescope.  But yeah, they had originally planned the   overwhelmingly large telescope to go the full 100  meters. But the problem was, they were looking at  

the budget and at like, I think it was gonna  be like two or $3 billion, they decided it was   too expensive, too expensive. And yet, of course,  obviously, here we are hindsight 2020 James Webb,   closing in on $10 billion dollars, is going  to be a 6.5 meter telescope in orbit. But,   you know, I think if you asked a lot  of astronomers Would you rather have   three overwhelmingly large telescopes or James  Webb, they would take three overwhelmingly   large telescopes. So who knows after the  Extremely Large Telescope, maybe we will see   the overwhelming the large telescope come back  online. ground based astronomy is getting very   powerful thanks to adaptive optics. Thanks  to interferometry. There's a lot of great  

technologies that are being built  into these ground based observatories.   And a lot of the technology that's being tested  out in things like say the Very Large Telescope   are going to be applied to the Extremely  Large Telescope. As I mentioned earlier,   it's the ELT that will be capable of seeing those  are sized worlds orbiting sun like stars around,   you know, other other stars. So, and that's  2026. We're just a couple of years away now   from from that next level of technology,  not to mention, the 30 meter telescope and   the Magellan telescopes. There's a lot  of really interesting telescopes coming   shortly, in the next within this decade. All  right, so more questions in a second, but first,   I would like to thank our patrons, thanks to  Barry Greenway, Andrew Alexander, Gregory Donahue,   Andrew Duffy, Anthony Paris, Alan Walker and  the rest of our 865 patrons for their generous   support when our videos early with no ads, join  our community@patreon.com slash Universe Today.  

Girl Sharma wood building a Lygo in space  increase our sensitivity to detect fainter   gravitational waves, there is a Lygo in space,  which is called Lisa, the laser interferometry   space antenna. And Lisa is being built by the  European Space Agency. And they've already   launched one portion of it called the LISA  Pathfinder, and LISA Pathfinder was one of the   satellites, the eventual final, Lisa will be three  satellites that will be flying in a triangle,   and they will be firing laser beams. And they'll  be measuring the distance of those beams very   carefully as they bounce back and forth between  the satellites. And then as a gravitational wave   rolls over the satellites, they will expand  away from each other and then contract again.   And you'll be able to measure these gravitational  waves. And Lisa will be incredibly sensitive,   especially to the kinds of gravitational  waves that that LIGO and other ground based   observatories aren't able to detect. And  one of the big ones that astronomers still  

they have no way to see right now are the  mergers of supermassive black holes. So we   can see the mergers of neutron stars, we see  the mergers of, of black holes, and we can see   the emergence of neutron stars and black holes  and, and maybe white dwarfs and neutron stars.   But we can't see the mergers of supermassive  black holes. I know it seems really weird,   but it's because it happens too slowly. That that  as to supermassive black, when you go to smaller   Black holes are buzzing around each other really  quickly, incredibly massive. And they're really   just sort of yanking spacetime back and forth. And  they create this very obvious signal that passes  

through the LIGO detector. But with supermassive  black holes, they emerge very slowly, because   they're so huge. I mean, they are millions,  sometimes billions of times the mass of the Sun   is their event, you know, they're going around  each other and as their event horizons merge,   they are causing space time to work, but in this  very long way, almost it's the difference between   say like ocean waves and waves in a in a lake or  a pond. And the And so Lisa will theoretically be   capable of detecting those much longer, slower  gravitational waves from merging supermassive   black holes. And that'll answer really fundamental  questions about what happens to supermassive   black holes when galaxies collide with each other,  because that's still a bit of an unknown question.  

One possibility, obviously, is that the  supermassive black holes merge together. But   there's another possibility is that, that they can  just bounce that, that even when you've only have   two supermassive black holes that are careening  towards each other, one can bounce off the other,   and I forget the exact sort of way, you  know, has to have a certain kind of kick,   and has to have a you know, the way that  they have to be rotating a certain speed etc.   And so we still kind of just don't know what's  actually happening. And especially if you've got  

like a three interaction with three supermassive  black holes, I mean, there could be huge,   supermassive black hole just just wandering the  Universe, and we don't know where they are. So   Lisa, and that's like, not due for launch, like  in the 2030s. Unfortunately, it's gonna be the   one that falls on for that. And then the plan is  to make Lisa better. So instead of having sages,   three observatories, you could have 12 in a like  a great big, I don't know what you call it. 12   sided die 20 sided die anyway. And so that is  called the Big Bang observer. And if you've got  

this sort of larger collection of satellites  working together, you could end up with one   that could detect the background gravitational  waves of the entire universe, that you could see   the gravitational waves that were generated  by the Big Bang as it was first happening.   And that would be amazing. And that's one of  that's like really one of the great dreams of   gravitational wave astronomy, because with  visible light astronomy, we can only see up   to the cosmic microwave background radiation, we  can't see beyond that. And that's like 300,000   years after the formation of the universe. But  gravitational waves can see through that and see   right to the beginning of the universe. So 2030s  Lisa, space based, and there's been a bunch of   other ideas, the coolest idea for a space based  gravitational wave observatory would have one   observatory at the Earth l four point another  at the Earth l five point and then another one,   on the other side of the sun at the L two point,  and that would form a gigantic triangle. And they  

worked out that, that if as long as you  were able to kind of move the spacecraft   a little bit in their orbit, if you gave them sort  of orbits within the L, four and l five point,   you could create this giant three sided triangle,  that was the Earth's orbit of the sun, that would,   that would always remain the exact  same distance, you just have to sort of   fine tune the way the spacecraft were moving,  which was kind of an amazing idea. So that   would be mind bending, I can't wait. Elvish asks,  What do you think is the biggest possible filter   stopping civilizations from advancing, of course,  I have gone on record many times as saying that   the I think we're alone in the universe. And the  reason I think we're lonely universe is because  

the idea of the great filter is too horrifying to  contemplate. So the idea of a great filter is that   you've got these various moments in history that  life forms are unable to be able to pass through.   So one example of a filter might be the jump to go  from single cellular life to multicellular life,   right? So if single celled life is very common in  the universe, but multicellular life is very rare,   because you've got this filter. And that's  a filter that we have passed, right? We have  

multicellular life. So we have passed that filter.  But there could be other filters in our future.   An example of a filter on our future might be  that we create artificial intelligence, and the   artificial intelligence wipes us out, or  we all decide to live in a simulation,   because it's better to live in virtual reality,  or ecological destruction or an asteroid impact or   something that we can't envision. And when I think  about the great filters that lie in front of us,   if, if life is common, and if civilizations  have all run up against this great filter,   and failed, then then what that means is that  the great filter is impossible to predict   that, that it that it happens inevitably.  And that you can't predict it in advance,  

and you can't prevent it and you can't prepare  for it. Because nobody has ever done it. And   that's a really scary idea that that there is  some event waiting for us in our future. That is   that is existential that will prevent  humanity from becoming a spacefaring   civilization. And we are what 100 years away  from that, right? 200 years 1000 at the most   from being able to send spacecraft to other worlds  and you know, you Even something as simple as self   replicating robot probes to other worlds, we  could be worse, it's going to happen very soon.   And yet there's this event that that happens to  every civilization. And they wipe themselves out.  

So which is it? The answer is that we can't know.  We can't know what the great filter is. Because if   we did know, then we could prevent it. And because  no civilization has been able to get past it,   we won't either. And so when you ask what your  question, what is the biggest possible filter?   What if the great filter is out there, then we  can, it is impossible for us to discover what it's   going to be until after it's already happened  to us. Yeah, which is horrifying, right? So   we're alone in the universe. Were the first that's  lalala. I'm not listening. That's why that's part  

of the reason why I have my my position is because  because great fealty idea the great filter is sort   of really nasty. Quim asks, If space time is the  same, why don't we generally only refer to it   being long ago and not far away. This is the kind  of thing that catches new space communicators,   which is that for stuff that's fairly close, like  the sun, right, the sun is 150 million kilometers   away, or it's one astronomical unit away, or it  is eight and a bit light minutes away from us. So  

taste light, buddy minutes. But the distance that  the sun is and the time it takes for the light   to get to us are equivalent to each other. And so  it makes sense to be able to describe those, then   same thing goes for anywhere that you could look  at here in the Milky Way. You know, if I look at   say Beetlejuice and it is 650 light years away,  then it is a distance that it takes light to   travel 650 years. But when I look at places that  are starting to expand away from us, especially to   go all the way out to the edge of the observable  universe, then the time the light has taken to   get to us is different from the distance that  the object was when the light was emitted.  

And is different from the distance that the object  would be now if you could see it in real time. So   the classic example of this is the it's called  the CO moving distance, but essentially the size   of the observable universe. If you look at the  cosmic microwave background radiation, which is   13 point 7 billion years ago, the light that was  released from the universe in at every point in   the universe has taken 13 point 7 billion years  to make the journey from wherever was released   to our eyes. And yet, if you were to measure the  distance, if you actually grab a yardstick and  

measure the distance to that light, where  that the That place is, you would measure   46 and a half billion light years to get there.  So how can light have been traveling for 13 and   a half billion years? And but it's 46 and a  half billion light years away in distance?   The answer is that the universe itself has been  expanding. And these things have been moving.   And so where it was when it gave off the light,  it's different from where it is today. And so the   sort of the, the the rookie mistake that space  communicators make is they say that something   is far away. And that's how far back in time it  is. And those two are the same and they're not.   And so astronomers, they talk in terms of a thing  called redshift, and redshift as a sort of a way   of measuring how far the wavelengths of light have  been stretched out by distant objects as they're   moving farther and faster away from us. And the  maximum redshift, the cosmic microwave background,  

I think is they measure the called Zed  z. Zed is like Zed equals 1000, I think,   is the cosmic microwave background. But then even  really close, you know, much closer than that.   They'll measure a number like Zed equals one. And  that's still really far. And so they will measure   objects in the Universe by how much that that that  light has been shifted into the red end of the   spectrum. And that's their yardstick. And they  don't care really about how far away they are,   or how long way the light has taken or any of  that. They care about how far the light has been   shifted. Because that helps them figure out at  what point of the universe they're seeing this  

object closer to the beginning. The Universe  close to our current day. That's a look at so   it's it's a tricky thing to try to explain this  and you have to be really careful about how you   say things when you're talking about distance and  time in the universe. supercharged is any feature   interview with Isaac Arthur planned? I guess. I  mean, we've talked a bunch we've done like three   I think interviews on my channel a couple of years  on his channel, we've done some collaborations.  

So yeah, if you want me to talk to Isaac  Arthur again, I'm I'm down with that.   But you should definitely check out Isaac  Arthur's channel. This is going to be a pitch for   Isaac Arthur's channel if you are into futurism,  terraforming. Sending ships to other star systems,   interacting with aliens, uploading yourself to the  matrix. You should check out space and futurism   with Isaac Arthur, he's, he's cornered the market  on neurosurgery masks. How many souls is ingenuity  

expected to tag along with perseverance with  its solar battery and heating? It drains?   How many pixels does that rotorcraft camera  have? So ingenuity is the tiny helicopter   that is bolted on to the perseverance rover, which  is like the coolest thing that's been attached   to a spacecraft, right? That you're going to  have this nuclear powered twin of curiosity,   which is already a Marvel with perseverance.  But it's going to have all of these tools on   board to be able to search for life on Mars.  And then at the same time, it's going to   have this tiny little helicopter that it's  going to be that sort of cuddled up under,   under its wheels, it's going to take the  thing out, deploy it on the ground drive away,   and then this helicopter is going to fly on Mars,  it's got solar panels on it. So it's going to  

launch off the surface of Mars, it's going to  fly around, it's going to try to take a bunch of   pictures, land for however long its battery will  last, and then it's going to recharge with this   solar panel on board, then once get enough  charge, it's going to try to do another flight.   How long will it last? Well, if you ever  flown a drone, like it's gonna crash on   the first flight? Come on, right? It's gonna  be doing this completely remotely automated.   There's no way they're gonna get two flights  out of it. Um, but no, seriously, I don't know,  

I don't know, this is this is we're in completely  new territory with a helicopter on Mars.   It's a mind bending accomplishment. And I think  that, you know, one of the one of the problems   that we've had, I think I might have mentioned  this last week, or somewhere else Anyway, um, is   that there's a lot of really great ideas. If you  go back and look at old NASA technical documents,  

they've been thinking about airplanes,  helicopters, single stage rockets. Things   like the starship have been thought of by NASA,  they've been thinking about artificial gravity.   They've been thinking about different kinds of  propulsion systems for decades, for like 50 years,   if you go back looking through old NASA proposals,  it's incredible what ideas have been thought of.   But the problem is that when you introduce an idea  with some level of technological risk, you have a   chance of destroying your spacecraft of ending  the mission. And so it's always this balance.  

If you want to get science done, you want to be  on a very dependable platform, you want the old,   reliable 486 as opposed to a modern, I don't know.  threadripper. Right. As your as your computer,   even though you get a lot more work done with  a thread Ripper, and 16 megapixel camera,   they go with something that's smaller and safer  and dependable. And the same thing goes with   alternative propulsion systems and things like  that. There was this launch that happened earlier  

today, yesterday, SpaceX launched 143 cube SATs.  And there was all kinds of ideas on it. There was   into military stuff, some educational stuff, some  research NASA stuff, tons and tons of little. And   we've been reporting on all kinds of ideas. And  I love this age. I think one of the the biggest   booms that we're gonna see in the  next coming decade is we're gonna see   cool ideas that have been waiting for the  prices, the launch prices to come down,   we'll finally get tested. In space, that  has never been happened before. I mean, it  

it took like 2030 years from when ion engines  were first developed and proven to work   to when they were actually able to fly in  space on Deep Space one takes a long time.   So the fact there's a helicopter on Mars is  incredible and whatever it does, like if it   flies once in crashes, it will be incredible and  and kudos to the team for thinking of the idea.   Getting it built. Getting Get on Mars. I can't  wait to see what happens and we're only like   three weeks away from perseverance arriving at  Mars so our Jonah asks How long would starship   be in service before NASA started incorporating it  into mission plans? It's a good question. I think   starship has a bunch of issues not like like  problems with it but but the way it's been   designed and developed that are going to be  not very compatible with NASA for a very long   time. NASA you know, with the loss of two space  shuttles NASA is very against any kind of launch  

vehicle that doesn't have a an abort system,  both Pad Abort System a in flight abort system.   They learned the hard way that you need to have  some way to have to have be able to have the   astronauts on board and and the space shuttle  didn't have it would have saved the challenger   crew wouldn't have saved the Columbia crew  although maybe if they had realized what was   going on. As the shuttle was flying up they could  have they could have aborted so the problem with   the with the starship is it doesn't have an  abort system. It just, you know, on the pad,   I guess if there's a problem with the super heavy  then then the starship itself could blast with its   rockets and get away from the super heavy before  it detonates. Once you're in flight again, if   there's a problem with the super heavy, then you  can get away from it. But once you are in flight,   you're the starship is the rocket. So and  then of course, the way they land is sort  

of terrifying as well. So I think that we're  gonna have to see dependability for a long time,   where these things are taking off and  landing and takeoff and landing. And then,   like they do NASA will put on scientific payloads.  And then they'll put on payloads cargo flights to  

the International Space Station and things like  that. And then maybe later, humans, but I'll bet   we're gonna see flights with humans to Mars from  SpaceX before we see NASA putting astronauts   onboard starship, that would be my guess. Chow de  Carvalho. How dangerous is the Kessler syndrome,   the Kessler syndrome is not as dangerous it's  been led people have sort of led us to believe   the idea of the Kessler syndrome is that you  end up with this. You know, as more and more  

satellites are launched, they're colliding with  each other, they're tearing each other apart, and   you're sort of filling space with shrapnel. And  that sounds terrifying, and that any spacecraft   that tries to launch is gonna have to go  through this. So turning buzzsaw of space metal,   and we'll just get added to the shield that  is blocking spaceflight. But the reality is,   it's more like friction, that more and more stuff  that launches, there's more debris up there,   you're gonna have to aim more carefully to  get through it. So it's not catastrophic,   but it's just going to be like another cost of  going to space. Alright, that wraps up the show,  

I think for this week. So if you want to get 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 with pictures,  brief highlights about the story and links so you   can find out more go to Universe today.com slash  newsletters to sign up. It's totally free. And did   you know that all my videos are also available  in a handy audio podcast format so you can have   the latest episodes, as well as special bonus  material like interviews with me? show up on   your audio device, go to Universe today.com slash  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,   everyone, for watching here on Twitch. And to  everyone who asked a question if you want to ask  

a question for an upcoming show. You can post it  in the YouTube comments or in Patreon or you can   join me live on my YouTube channel every Monday at  5pm pacific time thanks to all the moderators and   especially thanks as always, Chad Weber and Nancy  Graziano and we'll see you all next week.

2021-02-04

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