A Cosmic Crisis - Cosmic Queries

[Music] this is star talk cosmic queries edition i'm your host neil degrass tyson your personal astrophysicist and my guest co-host today is a friend of star talk the one and only paul mercurio paul hey neil how are you welcome back to star talk nice to be back great to see you again man let me just remind people who you are like you started out was it an investment banker or something yeah and that wasn't funny enough for you so you became a comedian well i started what the hell happened there and how much of a disappointment were you now to your to your family then and now i i can't even say that i was a lawyer i was saying i'm sorry i got it i mean no no bo you got it right i was i was doing m a law and i was like okay well mergers and acquisitions see you're still in it you're saying no sorry exactly exactly exactly i was gordon gekko with big lips and uh and then i decided well i want to really sort of you know be a little bit more scummy so i'm going to be an investment banker and then i i hadn't saw your um investment bankers wasn't scummy enough for you exactly exactly it's like why am i defending these guys when i could be one of them be making four times the money and uh so i'm like let me go jump ship and i was still doing uh immersion acquisitions but on the banking side and the difference is like the bankers sort of come up through the financial modeling to decide the value of the company and then they get into a price negotiation and they hand it off to the lawyers and then we negotiated so you're already in how that all that worked anyway that's what it seems like yeah yeah um so if you got put out of a job because an m a deal just tweet me you can uh here's my address if you want to come and burn my house down it might have been you it might have been me and then i thought um how could i disappoint everybody in my life including my wife i know i'll go into comedy and entertainment and start all over again and then that's what i did no i enjoyed your story we had lunch recently and you were telling me that the part of the birth you know the origin story of paul mercurio was selling a couple of handwritten jokes to jay leno for the tonight show that that's just i'd love that i'd love it and now you're you're you did the warm-up for a stephen colbert yeah yeah and then and the late show and the late show i wrote on the daily show worked on the colbert report and i work on that this show and then appear on the on the late show occasionally too okay so if i'm ever watching stephen colbert and his audience looks a little dead it's because you didn't you failed [Laughter] because you're supposed to get them all excited right no it's because i wasn't there and some lame-o called in for me it was a good one yeah uh yeah no it's a it's this weird sort of thing you can't do jokes in it because it doesn't work in that setting you need like an intimate space and with cocktail tables kind of space yeah yeah you know yeah you know and then you know angry waitresses serving around you that kind of thing and then uh just to remind people that his show is in the ed sullivan theater so it's actually a theater not just a little recording space right yeah it's pretty incredible i mean you've been to the show and i don't know if you saw it downstairs but below they have these huge timbers and an elephant painted on the wall and it turns out that they used to have the ringling brothers circus perform in the theater and they would bring the elephants in on the 53rd street entrance and they needed to put these timbers up to support the stage because of the elephants so just to be clear the ringling brothers came to perform at madison square garden not only on the end sullivan show so so this was like pr for the regular show right yeah that silver show to watch a free ring circus right exactly well a couple of the elephants for divas they wouldn't even go on the sullivan show they're like i don't need that and they're just they're just looking at their hooves like what what um do i do elephants have hooves no i don't think so i don't think so they're like i call them big feet i was starting to feel stupid when you corrected me then your answer didn't make me feel so stupid now they have those big feet and uh so yeah i mean so it's a it's a compact thing like in 10 or 15 minutes you gotta it's it's a weird to go into a tv taping for an audience it's strange because a lot of people haven't been before so you don't really know and i think sometimes they think you have to kind of actually be quiet and like polite and yeah yeah yeah because otherwise you interfere with the filming right right yeah they think they're right and the whole vibe is that they create this wave of energy and we kind of surf it so um i mean you know you've been on it they they love you i mean you've been heckled a couple of times we cut that out and at it and i can't believe somebody threw a pie at you from the balcony i thought that was highly inappropriate [Laughter] it was something like you haven't returned my email in three years and then he threw a pie at you i was like wow this guy's got a lot of enemies uh no well i like reintroducing you to our audience so it's great to get something appreciated so did you come loaded with questions from our audience and what's the theme today uh the theme is sort of a grab bag we uh okay we have those every now and then yeah yeah yeah but there does seem to be a little bit of a through line of sort of uh you know in terms of the galaxy and sort of uh okay measurements but let's if i know the answer i'll you know i read through these ahead of time i don't think you're going to know any of this no that's i will just end it here why don't you just have a glass of wine and i'll take over uh mr big feet and um all right so we'll get started then yeah let's do it okay i apologize on this first name it's a little tricky but i'm doing my best here it's uh haday uh wagomans and the question is do we know where hede comes from uh we like knowing their origin we do not know okay i just have the name um by the way and patreon i think yeah yeah all these are patreon right so patreon um they get perks for supporting the show and uh so we love them for that and here and here we have it so yeah so what do you have um if the universe expands at light speed how does it expand at light speed and uh by the way i've listened to all of the episodes of star talk radio you don't have to kiss ass you're going to get your answer here you don't need to well at least he said it at the end of the question right rather than at the beginning right that's that shows a little more class yeah exactly uh so yeah if the universe expands at light speed how does it expand that light speed yeah that's a common um [Music] concern people have when they learn of this and because they know fundamentally that nothing can travel faster than light so how is it that the universe could possibly expand faster than light in fact if you go to the early universe right after the big bang it was expanding way faster than the speed of light so here's here's where the rubber hits the road or the spaceship hits the vacuum or however that way however that'll work so so einstein's in 1905 einstein came out with his quote theory of relativity but that theory of relativity was in a very restrictive case okay and so it came to be known as the special theory of relativity not because it was special like you're special no no it's not that it's because it was a it was a limited invocation of the principles of relativity so it's a special case really is how is what it should have been called really and it would take him another 10 years to generalize the principles of relativity to a much larger more encompassing um concept and that which by the way which by the way proves 10 years he was lazy let's be honest you think what that is i could have done it i could have done it too anyway so it became the so the special theory of relativity broadened to become the general theory of relativity okay so that's that's what's going on there and so it turns out in special in the special theory of relativity it describes what happens when you move through a pre-existing space and time and if you're trying to move through pre-existing space and time there are speed limits the speed of light it's not just a good idea it's just what happens is it possible to exceed but you have to finish the line it's not just a good idea it's the law don't you remember this i'm sorry i missed it i'm sorry i missed it have you been living in new york so long you forgot how to drive and you forgot those rules about the speed limit exactly exactly i totally missed it yes all right it's it's it's not just a good idea it's the law it's the law you missed it you know i'm hanging these low low low-heated fruit so the universe so what's interesting is uh photons packets of energy do move at the speed of light but anything with mass cannot ever achieve the speed of light under the tenets of the special theory of relativity and what happens is the circumstances become oddly interesting right so if you're going to watch me move faster and faster and faster you will see that my time will begin to slow down you'll compare my clock to yours if i'm on a spaceship and you're down here on earth and you watch me fly by my clock will tick slower than your clock and not only that you will see the length of my spaceship shorten in the direction i'm moving and you will see that my mass has increased and i will have no idea any of that is happening so even though you see my spaceship getting shrunk front to back i'm in the spaceship and i looked behind me i looked in front of me and it's a normal spaceship so the point that einstein noted this is part of one tiny piece of his vast brilliance is that while i'm on the spaceship if i try to measure the length of the spaceship my ruler shrinks as well so i'll still measure the same length even though you're gonna say hey neil you know you're really shrunken up i said no i haven't and i take out my shrunken ruler and i say everything is mine is it's a is it is it okay so here's what happens that's a great question it's a great question so what um the reason well i recall the reason like that like someone made this a reason it is just the reality of the universe in which we live and it's that everybody measures the same speed of light no matter how fast you're going right so if you're on the front of a train let's say a train is going 60 miles an hour and then you throw a rock 10 miles an hour in front of you okay you're standing on the train and the rock is leaving you 10 miles an hour okay someone on the ground will see the rock go 10 miles an hour plus the speed of the train okay so those those the trains are only 60 they'll see the rock going 60 like going 10 and so the rock 10 in front of the train is actually going 70 miles an hour it adds for that person okay i was just thinking it would catch up but it does it no no it doesn't no no once you throw it it will fall but if you just throw it out ahead now watch if i send a beam of light in front of me i will measure to have the speed of light you on the ground try to measure that same beam of light even though i beamed it in front of a train and you also get the exact same value for the speed of light this is freaky right the speed that you measure for light is independent of how fast you're moving so einstein said how do i make that happen in the calculations the only way we can all agree that the speed of light is the same no matter who's measuring it is if my length shrinks as i go by you is if my mass increases and my time slows down so that simple observation about the universe that everybody measures the same speed of light forces all the rest of that to be true and that is the special theory of relativity okay so now 10 years goes by because he's just such a lazy bum and then he figures out how to think about this with regard to accelerations so not just how fast you're going but suppose you're accelerating suppose and what so he the full answer to this question would take an hour but i'm going to shorten it and say that the expanding universe is not an object moving within the pre-existing universe and therefore the speed of light plays no role in constraining it so it can expand at any rate of speed arbitrarily fast because nothing is moving faster than light within the medium it is the stretching of the medium itself and that's so and that was it allowed in the general theory of relativity which still contra contrains your speed if you're trying to move within the space itself and so if something can expand with no parameters is it is it possible to measure to measure that in any way what will happen is as the as the univ if so you'll see a part of the universe expanding and let's say it hits the speed of light well the light it tries to send you will lose all energy before it reaches you so it basically disappears and it creates a horizon for you and so yeah yeah so so that's what's interesting so there's more universe out there it's just beyond the horizon and that light will never reach you because the universe is expanding faster than the speed of light can come towards you so so yeah it's gone forever so you'll never even see the thing objects embedded in space moving at the speed of light or greater so the short answer to but uh you know if the universe expands how does it expand that light speed it is very complicated it's not sort of it's this or it's that it just depends on the medium and the circumstances no it depends if it's because the space is expanding not objects moving within the space at the speed of light so that's that's that's the fundamental difference there okay and there's a really brilliant reason how and why einstein came up with this concept of the general theory of relativity the equivalence principle and i i could get into it if we have time but we're going to take a break in like a minute but i just want to say that the short answer here is general theory of relativity allows space to expand at arbitrary speeds and it is not constrained by the speed of light whereas we are because we're embedded in a pre-existing spacetime and we cannot then go faster than life yeah i mean let me be clear you all are i am not constrained i'm a whole other being that is able to morph i'm i'm the bad guy and terminator there you go by the way by the way the terminator two to get you you know yeah okay i hate it when you correct me and you know i'm just i'm not actually correcting i'm just enhancing the truth of what you say wow you must be fun to get in an argument with your wife honey i'm not correcting you i'm enhancing you well enhance outside because you're not sleeping in this bed tonight so um oh so so science fiction authors know all about this limit of the speed of light and they don't want to violate that all right it's like sacrosanct so what they do is they come up with other methods that circumvent the speed of light limit like warp drives and what do they do they're distorting the fabric of space and time and traveling and surfing that or traveling through wormholes and these are all other ways you can get from a to b faster than a beam of light would have but you're not actually moving through space faster than light to accomplish it so like in in star wars which was uh you know we're going to jump to uh was it light speed hyperspace i do hyperspace get your vocabulary hyperspace is that is that plausible in some way like they've worked around yeah so because the future so you give them whatever whatever special engines they need but they were distinguishing the fact that they can't just accelerate faster than the speed of light something has to happen okay in order to engage that and and the streaking of the of the starlight that's kind of what it might look like if you sort of did that so i thought that's one of the three accurate things in the entire star wars series that is one can talk about that has any correspondence to physical reality uh the other is that jar jar binks is a very good actor we got to take a break but when we come back more cosmic queries on star talk with my guest co-host paul mercurio we're back star talk cosmic queries grab bag edition i got my guest co-host paul mercurio paul uh mercurio that feels like the planet mercury right was is that is there an r in your last name there actually is i had to change the spelling for performing purposes uh my my god-given name is m-e-r-c-u-r-i-o or god gave you that name that's interesting well yeah he and i are we're like that and you're on a last name basis with god well apparently i was born and a guy in a robe walked in and said your name is mercurio and then they don't know if it was god or a homeless guy but uh i'm going with god just so i feel important and it works every time yeah all right so so you're born mercury mercury and you took it out why while i was uh in a had a part in a show in los angeles and my manager called me goes there's a problem and i go what am i getting fired from this acting job he goes no but you will be the problem real problem is that there's an actor in the union with the name paul mercurio and i just was like i went nuts i'm like what are the statistical chances of somebody having that same name and it was this australian actor you may not remember but he was in this really good independent movie called strictly ballroom he was a i did see i was i was a ballroom dancer at the time i saw that very interesting oh okay and he was a great dancer and apparently the story there is he was a choreographer on the film and the actor they hired really couldn't pull the dance moves off so they put him in front of the camera and he acted fine and he had a career for a while and he did exit to eden with rosie o'donnell and some other so he got in the union before i did so for a while i was paul michael mercurio my my confirmation name was my middle name michael you saw yourself be so pious and i gave you the last name the confirmation god gives you another name hang on hang on i gotta heal a leper hold on one second um get some water you had lepers in your apartment good i'm not never visiting you it's my door man it's the best we could get with covin everybody else is on unemployment and uh and so i uh i tried three names for a while and the end of the story is that god forbid somebody could introduce you and get paul michael michael mercuria they couldn't say three names and get it right and so i dropped the first r in my name okay and you're curious but i got mercutio i got references to shakespeare i guess my name is sort of my i have attended i'm an aries so i don't know if you believe in astrology what do you think yeah yeah a little bit and uh that i'm sort of a mercurial kind of human being and my wife is easy anyway sorry that was too long an answer all that i all right so what do you have for the next question uh we're out of time thanks for tuning in everybody both are too long explaining exactly the absence of an r in his name exactly in his head neil's going why did i ask this more on this question all right all right david goldberg two parts hi dr tyson we get it you're a doctor back off uh how do astronomers know how old stars are that's the first question you know that's okay well there's another part to that yeah i recently read that they observed a moon forming around the planet near a star that is only six million years old and i was wondering how they can tell yeah okay so that's a that question is way deeper than most people know and imagine so we look out in the universe and how long are we alive at most 100 years and stars live billions of years the universe has been around for 14 billion years we're not sitting around so there's one getting born and there's adolescence and then age and dying we don't have that luxury all we can do is take snapshots okay we take a snapshot over here a snapshot over there and we line it all up and we scratch our heads okay so now by analogy let's do the same for human beings okay so let's say we are some insect that lives for one day and we want to know how do we decide how old humans are that we encounter but we'll only live for one day okay so i i amass all of my fellow insects together so let's take photos of humans throughout the day bring them all back and sit down and scratch our heads if the insect has a head so what will they see they will see this a building with tiny humans in it okay very tiny how big is this insect this is freaking me out no it's okay i'm trying is it going to have to be a mantas it wouldn't have to be an insect just another creature who's curious about humans as life forms the way we are curious about stars okay so that so they'll see they'll see women sort of facing this building with distended bellies okay they'll see in the building they'll see little humans and then they'll and they'll also see women exiting the building holding these little humans okay so that's kind of interesting all right hold on to that for a minute they will see wooden boxes going into the ground okay oh what's that okay oh by the way in the same building that has the women with distended bit uh bellies they will see other humans laying down that are very wrinkled maybe or um okay do they see do they see my super not fixing the leak under my skin yes they will they will catch that and can they kill him for that that's all i really care about okay so you can ask um do this life form are they born in the earth in boxes because you don't get to see the box move these are snapshots right right and do we do like seeds like plants and we take them out of the ground and they start out wrinkly and then they get healthier and healthier and then they begin to shrink and then disappear okay because you don't even know the time vector when you're just looking out in in the universe so you start assembling this and once you bring enough of this data together you can start constructing a timeline of a human being and you might say okay um here's another subtle point you ready some people have this stick in their mouth and there's froth in their mouth okay not many it's maybe one in a thousand okay how what fraction of a day are you brushing your teeth right it's like a couple of minutes out of 24 hours so most people will not be doing this some will be so is it only this kind of person is only ever brushing their teeth and no one else does or does everyone brush their teeth it's like watching people running for exercise these people are sort of they're they're moving faster than most people are moving in terms of walking what does this mean where what does it mean exactly or what you won't see them moving you'll just catch them with longer strides in a long stride with wearing fewer clothes like you know wet from sweat whatever that yeah right right so all of this has to go into a box that you sit there and scratch your head and it's like a puzzle really and you say well this maybe this comes before that oh we we got this now the distended bellies and this this place and the women and and do i even know that they're women well statistically they have longer hair and so does because does everyone get a distended belly so you have to think all of this through for me the one of the more intriguing ones is trying to figure out whether one kind of person is the only one who's ever what you find in the bathroom or does everyone go to the bathroom you just didn't catch it because it doesn't take very long okay okay because you'll just miss it all right but you will be able to if all this data that you're collecting a very quick determination can be that there's only two types of these beings a naked man looks one way a naked woman looks another way well to you but if you are a praying mantis do you even see the difference i mean when you see a pramence when you see no when you see a pigeon are you saying oh yeah that's a female pigeon that's a male pigeon or you look really different no they can tell each other apart well when i look when i look at pigeons i try to look at them as more substantive beings i'm not shallow like you like hey that's pitch that picture's got a nice body tired beings right so what may be obvious to us would be completely mysterious to another creature you don't run around and judge the gender of goldfish right you have no clue because we don't have eyes for that we don't no no but i'm not saying that they that they would say today it's gender but they'll start to see a pattern that there's two these these beings look one of two ways in terms of this not size not okay but they do but not all of them okay so you know uh elementary school children okay um unless they're completely stripped down they're just they're just smaller humans right and so so the differences grow through middle school and high school of course but then you still have to figure that out that's my only point so fortunately just for this visiting praying mantis or whatever creature it was there are billions of people fortunately for astrophysicists there are billions of stars because if you only do something one in a million times and i have a billion of you out there i will catch somebody in the act doing it every time right all right do you need the large numbers to see the things that are rare okay and then to start putting put finding a pattern to write right data and to create the temporal nuances of what's happening simply from snapshots so we look out in the universe and we say hmm there's a gas cloud over here all right and i see some stars deep within it by the way what are stars made of they're made of gas hmm maybe that's a stellar nursery because over here i see stars and there's no gas so where did they come from wait could it be that these stars dissolve themselves into a cloud that could that that could be it's analogous to do are they born in these boxes and the box doesn't come back out can i reverse or are they born and then yeah correct so but then so here's what you find you ready you keep doing this and then you find out wait a minute this star just blew up oh my gosh what kind of star is that oh and you look very carefully and we have other ways to determine it's a very high mass star only high mass stars blow up and then you can look at the fragments okay but but wait a minute so so it so because you could ask do stars are they born with very high mass and then use up their mass over their lifetime and then just disappear right that's another one right that's the i start out big and i eat up my own flesh and i disappear but no it turns out stars are born at a given mass they use some of it during their life but it's only a very small fraction of it it turns out and the high mass ones blow up with hardly any difference in their mass from when they were born and the low mass ones never blow up and they have a different color and and some stars never wander far from their birth from their nursery and you piece all oh then you find out then you find out there's a whole bunch of stars here that that the the gas is almost entirely dissipated now you can't make more stars so they must all be the same age oh my gosh and now i have a cluster of stars with the same birth date well how about this other cluster over here well the parameters are a little different i see less gas among them but these other things have changed so maybe after a million years after billionaires these things are taking place so this took decades with the most powerful telescopes in the world and one of the leading telescopes was mount palomar in california the hale 200-inch telescope really put teeth in the stellar evolution [Music] understanding of of this universe so it is it was a very hard task it took many brilliant people over many decades not only the theorists to try to figure out what's happening inside the star that would cause it but the observers he was saying i see stars here but not there okay how come i don't see humans in the middle of the desert okay maybe and how can i see more humans where there's water oh maybe you need water for some okay just keep doing it right you keep doing it just it's it's sort of this never-ending it's a never-ending thing and the thing about the universe is the bigger is your sample of stars the greater is the chance you will see something that is so rare it only happens once in a billion or trillion times all right and so every now and then you'll see a headline saying astrophysicists discover a new black hole that doesn't fit anybody's model or understanding or well because it's the millionth black hole we found right so uh you know if i if i search enough people i'll find somebody who has every disease you ever see advertised on television right right no i'm serious everybody's got there's something this isn't one in a hundred thousand and one in a million or what is it tay sachs is it sickle cell is it uh it's my aunt christine she's got every pain under the sun my back my head then she'd be a gold mine for the investigating aliens okay she's got all the data that's a perfect place to send her actually let's put her on a ship all right we're going to wrap up on this we got to take a break oh yeah take a break okay damn i'm taking so long to answer no maybe a lightning round for this for the third and uh third period absolutely uh and we're gonna be back right after this quick break we're back star talk i got my guest co-host paul mercurio paul how did people find you on the internet uh at paul mercurio no that was a long-hanging fruit you could they find me repulsive paul i'm handed paul i don't want i don't want to be the teller of your the jokes that are just dangling i don't i forgot that you're so evil and uh uh thank you i have bad breath i have that's how i find it yeah they find me repulsive that's actually a perfect way of describing me um call me curio on on twitter is that oh you don't care don't you you just dude i want my people my people wanted to know how to find it yes at paul mccurio o one r m-e-c-u-r-i-o-1-r we talked about this earlier i had to drop the versus r and paul mecurio.com you know that's one word paul mccure paul mecurio and instagram or tiktok instagram twitter facebook i'm thinking about starting tick tock but i don't know if it's tick tock is like a commitment you got to like be ready to get in yeah yeah and i'm not you gotta dance and i don't know that's nobody wants to see that yeah so you dance you're correct nobody wants it i didn't know you were a ballroom dancer is there anything you haven't done like this is amazing there's two things yeah but no i was a on a competitive international latin ballroom dance team wow yeah yeah yeah there's a team so there were eight of us eight couples and it was the full choreography it was it was a yeah good friend of ours does it and she loves it and she's in great shape from it too it's amazing yeah that movie came out right at that time and uh so it was we it was a you know field trip for the dance group so what do you have you gotta jump back did i finish the second half of that question because we found a moon orbiting a planet orbiting a star so what we find is the stars that are being born in these gas clouds we also see disks of material and then we say to ourselves could these disks of material be the proto material that will then make planets in orbit around the star and so sure enough this is what we observe so yeah and so you can observe planets forming around stars and then the planets themselves some of them have discs and out of that disk they would have their own moon so it's pretty cool can i ask a quick follow-up on something you said in the last segment no unless you're a patreon member you can all right here we go um okay toby sonenberg hi neil could you please explain what the crisis in cosmology is what are the what are the some possible ways the crisis can be resolved what do you think is the most likely resolution oh this person is doing some homework there okay well so old-timers it's hard to call it a crisis it is a crisis but for old-timers it's really hard all right i'm an old-timer i i come from an era an epoch okay where we didn't know the age or the size of the universe because they're related to within a factor of two okay a factor of two is the universe 10 billion years old or is it 20 billion years old and if you put all the data together people sort of picked and chose and sifted and there was the 10 billion year camp and the 20 billion year camp and they were warring factions for many years but there are two methodologies too that's right so the methods are different the the chosen objects cosmic different so so this is how you get this divide and it's on the frontier and eventually with better telescopes better data which is how this is always solved all right that's the good thing about being a scientist you can get into a fight and in the end you both agree it's an un uh it's a it's an unwritten contract that you and i have that either you're right and i'm wrong i'm right and you're wrong or we're both wrong and they'll reach a point we say we need better data let's go have a beer okay so that's how that works right there's no there's no dual there's no who shouts the loudest that's not how we that's not how we roll so but there's a but there's an analysis that looks at sort of historic data and then there's one that takes it looks at sort of current state of things and those or there's another one that says here's instructions for the next wave of observations i need you to look at it this way because that'll help me resolve this uncertainty so with this factor of two warring factions with new data especially with the hubble telescope and the uh observations of the cosmic microwave background with two satellites three satellites that were engaged in this one successively more precise than the next you we so it turned out the uncertainty was no longer a factor of two it narrowed and of course the the actual answer ended up somewhere in between all right so we're now at about 14 billion years no one is saying 10 or 20 anymore all right so you'd expect that if the two warring factions the right answer is probably somewhere in between as it turned out to be all right so we so we're all happy 14 billion year old universe and then people start looking more carefully at it they use this method and that method and our observations are so precise people are saying and i forgot the two the exact two numbers is it 14.0 and 14.6 there are two different ages well it says the crux of the disagreement is that 67.4 plus or minus 0.5 that's the value of the hubble constant which then gives you the age of the universe so so give me those two numbers that's my 67 and the other thing is 7.4 uh plus or minus 0.5 and 73.2 plus or minus 1.3 so these two numbers kilometers per second per megapixel right so those two numbers are the fabled hubble constant and you use the hubble constant to get the age of the universe i was content giving this answer in the context of the age of the universe but now you threw in the hubble constant in units of kilometers per second per megaparsec because clearly you don't want to do your job thoroughly and i'm covering your behind i gotta carry you go ahead go ahead mr i know i know the universe go ahead so the the hubble constant version of the age of the universe is is the hubble constant um 50 or is it 100 okay that gets you these two different ages of the universe all right uh if the hubble constant is 50 then the age of the universe is 20 billion years if the hubble constant is 100 then the age of the universe is 10 billion years so but point is if you want to speak in hubble if you want to be hubble constant fluent that's fine those two numbers which used to have a huge uncertainty no no longer has a huge uncertainty but now they each have their own camps because the uncertainty in each number excludes the other number okay so we measure those two numbers so precisely that the 73 doesn't allow the 67 in its error bars in the on range of uncertainty you know the uncertainty when you read uh election polls leading by sixty percent plus or minus three percent okay that's an uncertainty where the data can't distinguish so if you put the uncertainties around those two numbers the uncertainties don't overlap so that's a crisis in cosmology well what is what camps are you in and and i'm just saying to call that a crisis what a luxury of precision measurement right you would prefer the crisis because you you as a as a scientist like the challenge of trying to figure things out and come to resolution and this is a challenge still for you and when you have a crisis uh it energizes people that's correct we call it a crisis because the two had those two numbers had uncertainties that overlapped then it's just a matter of time you get some better data it might be that these two methods because it uses different methods too can you just hit on that for a second i mean maybe everybody listening knows but like and which method do you subscribe to because i don't i don't i i i don't i have no such investment in my emotional energy i step back and i embrace it all it is wow this guy just got really esoteric and can i have some of what you're smoking in the break because that was a pretty awesome answer man no it'd be something like you want to measure the the length of uh i don't know uh the length of some object and one person pulls out their pocket ruler and they do it another person pulls out a laser and another person pulls out like an inch worm okay and then they get three different results right but every time they repeat it they get approximately the same results and the results don't agree with each other right so you have to say to yourself one of these results is wrong or maybe the inchworm is relativistically affected i don't know you have to you know i mean it could force another understanding of the world third measurement i mean i i mean they both i mean they both seem valid i mean one is when the universe began and then using theories to predict today exactly they're completely valid and that's why we're scratching our heads or they they are irreconcilable and there's new physics that we need to put on the table that tells us why that's we all love new physics because it open it's like you you broke through a door and on the other side of the door is this beam of knowledge and wisdom that could shed light on other stuff that had you that still keeps as you scratch in your head and and let me give an obscure example of this we have what are called gps satellites you heard them and they orbit they're in a place in earth's gravity field where their clocks tick faster than our clocks okay all according to relativity if einstein's relativity had not yet been discovered and we launched these satellites for the sole purpose of establishing a coordinate grid on earth where timing is essential we would see that it would constantly be sending us time that's too fast and we'd say engineers what did you design you must have made a mistake go back to the circuit board go fix it check your drawings we would first assume that there was some mechanical problem with it and the engineers say no here's the here's the twin of it on earth and it's cats and no so well what's going on we can't we can't figure it out and so that would be a dilemma and then einstein would come along and say we have the general theory of relativity that's explained trivially bada bing a whole new field of physics opens up so most crises in science lead i hate the word crises because that yeah it implies human yeah exactly um dilemma how about dilemma how about that most dilemmas lead to uh physics you break breakthroughs that's there you go so that's the whole story there yeah well i knew that i just didn't want to say anything um lightning round yeah we're gonna do lightning round okay we got some really great questions that we want to get to taking too long to answer these no you're not it's always interesting i fall asleep in the middle but then i wake up um all right peter peter jacobs while i'm facing the chalkboard that's when you catch up on your nose yeah you're reading i'm on your feet shooting spit balls at your back of your neck um peter jacobs uh we're gonna do he's got two questions let's do the first one if two black holes collide uh can we tell their relative uh relations with uh ligo and how do they affect the final rotation of the resultant black hole excellent so this is lightning round so ligo the laser interferometer gravitational wave observatory is exquisitely tuned to look at the ripples through the fabric of space and time pred predicted by einstein in his general theory of relativity that when you have a disturbance a gravitational disturbance in the space-time continuum it sends a ripple moving at the speed of light and two colliding black black holes will do that before they built ligo they set up models of what all manner of black hole collisions would look like equal mass very different mass uh slightly different mass what was the basis for the models is this is i'm not making a joke is this analogous to sort of this praying mantis taking a snapshot of of us on earth and putting it because we're not going to have a million examples here so you want to set up a catalog that because you know general relativity it works we know black holes we think we know what will happen when they collide and so we say okay here is the gravitational wave signature that we just measured let's hold that up to our catalog and which one does it come closest to there it is a 30 solar mass black hole and a 4 and a 15 solar mass black hole there you have it now depending on how far away they were when they started their spiral they have what's called angular momentum and this is the momentum of rotation and that some of that angular momentum is carried away uh but uh i i don't know if it's most but much of it remains within the system and you have a rotating black hole so black holes rotate too just like everybody else okay we're going to get to the next one thomas you no no he had a second question you said he did oh okay i was just trying to get to everybody so i figured let's do it okay uh why bother sending a probe to another star when it will most likely find one we sent later um isn't that statistically unlikely though i think he meant the opposite of that i think he might what he might be saying is if you send a probe to another and i don't want to invent a question that he's not thinking but here's a version of that that i he might mean you send a probe to another star it'll take 50 years or even even you know okay but in those 50 years we invent a way to tunnel or wormhole to the star and so you so you get there faster than that would have ever arrived because when we sent it we didn't have that technology yet but it developed so there it is just passing it by saying hello right right right so people have argued why don't we wait until the technology is better uh and then do it right to send the probe to right but correct but it's not like we're doing it wrong is that i mean that sort of presupposes that we're getting information that's inaccurate or no no no it's just it says why bother right if if you're gonna say if you're in california and you say we discovered gold put the notice on the back of a tortoise okay and send it back east you can say no let's wait until the railroad is built or we'll have to wait until right now let's make it a little past the turtle in st louis you know we'll get it will be better so i think that might be what he means but okay okay keep going thomas hugh uh hello team has anyone tried to uh calculate the cost and natural resources of planet earth if spacex would follow through with the plans to colonize mars so that that implies that the colonization of mars requires taking natural resources from earth to put it there but if you're going to colonize the way to do it is do you do everything in situ okay you want it this is the buzzword in situ resource utilization isru google it okay and nasa has full running pages and when you get to a destination dig in the soils get the carbon dioxide split it get the water split the water molecule you get oxygen you can breathe it the hydrogen you get a rocket fuel all of this is what martian the movie two hours thank you hello do we need anything else to be matt damon the most brilliant second most brilliant next to neil degrasse tyson man in the world anyway go ahead so ideally that's what you would do otherwise no i don't whatever they have to take to have lunch for a year that's not going to throw earth off its axis a lot of subway sandwiches that kind of thing um real quick we have to wrap up i mean what are some of the advantages of colonizing uh mars well if an asteroid takes out earth then humans don't go completely extinct but that's a very negative attitude no i don't i don't i i'm a contrarian there i don't see i i don't even agree that that's why you should do it so we have more eggs in more than one basket if you have the technology to go to mars terraform it colonize it with a billion people it seems to me you have the technology to deflect that asteroid that's headed for earth okay oh we're destroying earth with global warming and the billionaires are all escaping and they're going to form another planet and then they're going to terraform that planet because elon is into terraforming it seems to me if we have the power to terraform and you redirect the folk into earth then we have the power to turn earth back into earth yeah okay so yeah don't worry we're cool here all right one last question let's slip it out want to slip one more in okay this is um alexander wiznet if gravity is due to mass and acceleration could we get an object with enough gravity to pull something at the speed of light if you fall into a black hole basically you come near the speed of light as you become the end and what happens is as you come near the speed of light uh things we it's it's harder to distinguish you as a blob of mass from you of what would then become a blob of energy so the mass energy equation very much favors the the conversion of matter into energy and so um so yes is the answer and that happens in black holes all the time and if you want to if you don't believe me try it call me up tell me hey neil i'm falling through a black oh just like you said just like you said i think you're breaking up a little oh my god i'm breaking up can you hear me now wait let me go to another this was not a good idea and then neil makes some notes and moves on with no emotionality about it uh we are done dude thanks thanks for coming in for this this is so fun and it's good to see you hadn't seen in a couple of years nice to know you're still out there and yes and holding down the cold bear for it absolutely are you going to be back on sue we got to get you let's colbert i got it i i got to write another book to get back on i got to earn it you know all right that's what that is let me put a word in for you you know this up and coming scientists you might have heard him uh yeah he's got a thing or two uh thanks for this is always great it's awesome you know what i said i was on his show march 2020. like march 9th all right it was like the last week that he you're the reason covered shut everything down and he says what do you think of this covert thing and i all i said was it is an experiment in whether humans will heed the advice of science and medical professionals right and that's what i said okay that's all i said and we're continuing this is an experiment that's a show or not a day show for another day but yeah that's a really great answer and you hit it on the head what it is this is uh we out thanks paul this has been star talk cosmic queries edition and i've been your host neil degrasse tyson as always bidding you to keep looking up [Music]

Channel: StarTalk

Views: 333,107

Keywords: startalk, star talk, startalk radio, neil degrasse tyson, neil tyson, science, space, astrophysics, astronomy, podcast, space podcast, science podcast, astronomy podcast, niel degrasse tyson, physics, Paul Mecurio, comedy

Id: E9Beyht-gzA

Length: 53min 27sec (3207 seconds)

Published: Thu Aug 12 2021