The Long Arc to Scientific Understanding — Live from the Museum of Natural History

he discovered Pluto but did not live long enough to see Pluto demoted that's why I said maybe it was a good thing that he moved [Music] on so to infinity and beyond is an exploration of hum humans standing here flat-footed on Earth looking up and wondering what is that up there can I ever get there will I ever get there is it impossible what what are the fits and starts that we go through in order to achieve dreams that at any one moment feel like they are impossible feel like they're at infinity and then you achieve it you say hey I'm on a new Vista and I can see far beyond anything I saw before and to me there are now new Infinities other unattainable goals that sit before us so I want to I want to impress upon you the challenges we face as scientists when we make discoveries you read about the successful discoveries you don't read about the failures cuz nobody reports about The failures but the failures are kind of important too and you need to know there's some questions for example that have no answers you say what what do you mean by that I got one for you ready okay do you know this question has no answer did you know that ever thought about this how tall are you 5 she's 5'4 not five4 and a half flat flat 54 just exactly 54 okay let's yeah or no yeah let's let's let's see so here you go okay there's your pigtails um are you exactly 54 well let's go find out on the measuring tape so there we go and wait a minute wait a minute these lines have widths wait a what what how do you know you're exactly anything if if you are you on the the right hand side of this or the the the upper side the lower are you exactly in the middle do you even know this no you don't because your measuring stick only goes to at best a 16th of an inch and nobody gives their height to 16 of an inch you would worry about the person who tells you that consider also that you're about a half inch taller when you wake up in the morning than when you go to sleep in some cases a full inch taller NASA knows this oh by the way you you're taller because gravity isn't shrinking you assuming you sleep horizontally I'm hoping that's not a big assumption here so gravity shrinks you and NASA knows this do you know that the space suits they design for the astronauts on the Launchpad are typically two or three inches shorter than the space suits they use when they Space Walk Because by the time they Space Walk they've been in zero g for days and days and days the the discs expand out they get taller they can't they can't fit in the space suit that they once were so this this this goes on how long is the coastline of the United Kingdom and you say say well that's a weird thing why is that even a question I'll tell you how interesting that question is there's an entire wiki page with that title okay it's not just some one answer again these are questions with no answers well how would you measure the coastline of the United Kingdom or at least the main island Great Britain I guess it would be so let's take a look all right that's not a very accurate way to do it with the 12 match sticks but it gets to a first pass you take all these sticks and then you lay them out and measure the length that's a first pass at the coastline but the actual Coastline will be what longer or shorter than that longer of course how much longer well let's do a better job let's use smaller match sticks okay we use small that's a better job we get in the nooks and the crannies okay mostly the crannies I don't know the difference between a Nook and a cranny but that was fun to say uh anyhow but it's look at it's missing some pieces over here this will get a better answer than that one but it's still going to be wrong is it going to be too long or Too Short once again too short well where does this stop how short do you have to make your match sticks to do this but why don't we use a string then not line segments let's use a string we can do that and those little little bitty bits that stick out but wait a minute let's let's zoom in okay wait did your string include go around these rocks did are these rocks even part of the coastline do you even know how to think about answering that and it doesn't stop there are you making your measurements during high tide or low tide the question how long is the coastline of the United Kingdom has no answer you can look it up and it'll give you an answer but it's you just have to agree that that's the answer it's not the answer because there isn't an answer no there isn't the answer there's only an answer so don't go to One Source and you get one number and another source gets another number and you want to call one Source wrong and the other source right no measurements always have uncertainties at all times and in science is all about measurement uh I don't publicly reference the uncertainties in the measurement as errors but that is what we call it in science publicly I call them uncertainties which is makes way more sense to the Public's ear then these are errors they think you're messed up in your measurement no you didn't mess up in your measurement you're 54 with a plus or minus on there that you don't care about okay let's keep going what is the shape of Earth's orbit you guys are coming I'm you know I do astrophysics you have probably some Cosmic fluency so you tell me what's the shape of Earth's orbit ellipse you everybody knows it's an ellipse it's a everybody knows that okay so let me show you we can quantify how elliptical something is it's it's called ellipticity the zero is a perfect circle this is a low ellipticity shape in the upper right uh 0.03 it's still kind of circular looking finally we're getting something that looks like a you know red blooded ellipse okay so which of these is Earth Earth orbit would you say the top left top top left and well it's not a circle we know that top right top bottom left bottom right okay okay because you were told it was an ellipse you were told this okay uh the eccentricity of planet Earth is the upper right diagram the upper right diagram if I said Earth's orbit is a circle you'll say no it's not it's an ellipse but you couldn't pick out the ellipse that it was all right that's just CU you didn't know that's fine but let's keep going do you know well do you okay that is not how elliptical the Earth's orbit is that is false yet this is displayed in a book feeding your the the errors of your ways but so it's so even though we're nearly a perfect circle it's still not even that shape why because that is Earth on the left and that's the Moon the Moon doesn't orbit Earth Earth and the moon orbit a common center of gravity so Earth is kind of jiggling like this while the moon is going around like that so if Earth is doing this while it's on an elliptical path it's doing Loop to Loops that's not a perfect ellipse that's a loop-to-loop ellipse not only that the entire solar system is moving through the Galaxy through the G the sun is dragging all planets and comets with it what does that look like we have a loop to Loop and it's helical through space none of these is an ellipse so to say it is an ellipse just no just we will approximate it as an ellipse and be happy with that but again these are the challenges not only as a scientist how do we characterize that but also as an educator am I going to teach all of that in one Fell Swoop or do I start out saying Earth's orbit is a circle then you get an idea we go around the Sun it was slightly off from a circle they're Loop to Loops there's a helix you you build on that that's fine but when people say I have the right answer that's why while I'm entertained by shows such as Jeopardy the idea that here's the answer I can't there was one question one one year fact kareim Abdul Jabar was the contestant and he got the wrong answer but for the right reasons but they couldn't give it to him because his answer was wrong but he was Thinking Beyond the question the question was which European country has the largest land area okay which country is it Europe are we is Russia part of Europe when did that happen did Russia take over Europe while I wasn't looking it's a part of Europe so uh he mentioned Sweden and he said how can you be Sweden what he really meant to say was Denmark but Denmark wasn't the answer they were looking for they were looking for like was it Spain or Germany or something but one of I forgot one of those it's Denmark why because Denmark owns Greenland yes he knew this but he got the wrong country he was thinking it was you know he was Scandinavian but again running around say I have the right answer and your answer is wrong no I I don't play that okay also I just did this I tweeted this once because I had nothing to do that day um I calculated the ellipticity of the Oval Office in the White House okay if you want to know yes I did this and posted it so its exent is 6 so it's very elongated and by the way which means you can focus sounds in one part and hear it in the other part yeah so if the president is at at the desk then the couch area here president can Eaves drop without them knowing but why would they be in the Oval Office telling secrets that they don't want the president to hear so that's a stupid example but it would happen that way if it did let's do more what is the diameter of the earth you can look this up but wait a minute are they including the mountains okay are the mountains there the diameter are they going to the to the Mariana's Trench where's the Mariana is it up there somewhere yeah the marana's trench that's the deepest part of Earth's crust as any geologist knows and that's if you want to test your submersibles you do it there if it's going to implode that's where it's going to happen especially okay so by the way going into space is way safer than going to the bottom of the ocean all right do you know the pressure difference between your capsule and empty space one atmosphere the pressure difference between sea level and the bottom of Mariana's Trench squash you like a pancake so where are you going to measure the diameter okay how are you going to do this by the way okay if you measure us from pole to pole it's 7,900 miles you measure it across the equator it's 26 miles bigger so Earth is oblate by a little bit this obl or prolate oblate is hamburger prolate is hot dog okay and if vegans can one day give me replacement foods for that I'm happy to include that but they work really well right now okay and we're slightly wider below the equator than at the Equator so we are a pear-shaped oblate spheroid and look at I have it accurate to Miles there what's what's that about here's something Earth is practically a perfect sphere you say no it's not there's a mountain sitting in front of me what do you mean we're a perfect sphere well how big is the mountain compared to Earth how big is that do you know the distance from the bottom of the Marian trench to the summit of Mount Everest do you know what that distance is okay any idea 12 miles thank you love you all 12 miles and for reference the length of of Manhattan is 13 miles so this if you have any used CU ball on a in a pool table it will have dings and nicks in it far greater than any surface features on Earth's uh on the planet Earth and so Earth is smoother than any used tub ball just keep that in mind what else how about what is the diameter of the sun ought to be able to measure that look that up you should be able to measure that okay but wait a minute it's a well it's a ball of gas that's right how do you measure the edge of the gas okay I okay here let's look at a different wavelength of light what's the edge of that yeah you go and measure that okay you come back and tell me it depends on what wavelength of light you're using will give you a different answer as a scientist we confront this we don't know going in that we'll have different answers but we got to be ready for it and not walking around say I have the answer that's not how this works you say I have an idea I have a way to make a measurement and I will report the measurement and compare it with other people's measurements they might ask the question differently so now tell you a little bit more about data let's start out here uh Galileo this is a uh this is a plaque uh of a painting of Galileo that was gifted to the haen planetarium in 1964 on the 400th anniversary of his birth it's a painting by Suman Justice sustman and here it is uh that is hanging in the per library of the Hayden planetarium that is Galileo about 10 minutes before he died looking very sad uh what did Galileo do oh well in 1610 he looked up and published his observations of the night sky including Jupiter's moons H that's interesting the title of his book was Star Messenger I borrowed the title of that book from my book from a year ago in Latin siderius nunus and he drew he looked up and he saw oh by the way he saw these see these star things drawn there he saw them move back and forth across Jupiter and but they looked like stars he couldn't see a disc there were just Points of Light so to him they called them star and he called them medician Stars why the medich was his was his you name it after the rich people who pay your way okay that's how that work that's always been that way okay the medes all right which medich oh so wait let me zoom in with folks in the back row so you get a sense of this yeah so he's drawing this and tracking them with his telescope so here's what he's doing all right he is this is a this is on a loop but these are the four brightest moons of Jupiter and they orbit Jupiter oh my gosh Earth is not the center of motion stuff can go around Jupiter too yes he named him after Cosmo II medich Kimo and that's not how long he was Grand Duke of tesy that's how long he lived by the way um through the early 1800s uh half of all people born were dead before they turned 35 yet all those people ate organic food their air was clear their water ran pure their game was free [Music] range still couldn't get past 35 on that one Science Matters okay this painting is by the same guy guy who did Galileo hanging in our offices uh so he died at 31 of tuberculosis which today hardly anyone possibly no one dies of all right those four moons are called the Galilean Moon we we don't call them the medician moons we named it after Galileo which I I'm glad we did so now oh by the way we've discovered some more moons of Jupiter uh this is a zoom out and you get to see uh so IO Europa ganam and Kalisto should come in next where are you Kalisto there you go those are the four moons discovered by Galileo the inner ones he couldn't see with his telescope nor could he see the rest of these as they show up those are 63 moons of Jupiter known a few years ago but since then we've discovered more moons of Jupiter so here's the point when Isaac Newton came up with his theory of gravity it worked for the Earth and the moon and earth going around the Sun it worked for the planets it even worked for Jupiter and its moons so you got to figure out this is a this might be a universal law of gravitation planets and our moon Jupiter and its whatever those Starry things are the medician things and for us going around the Sun we're testing the limits of these new ideas this is a bus of ISAC Newton I have in my office he's not always staring at me like that I usually have him in the back but Isaac Newton my man again I'm trying to get sympathy from you for what we go through as scientists and how careful we have to be so William hersel who's somehow always looking to his left I don't understand why uh he accidentally discovers planet Uranus that's orbiting Beyond Saturn first time anyone had ever discovered a planet Mercury Venus Mars Jupiter and Saturn are bright enough for the naked eye and the Ancients knew about it the caveman knew about it so no one is credited with their Discovery Uranus was discovered by William hersel except he didn't call it Uranus at first he named it after the king so for a while I have textbooks from a period right in the late 1700s and they enumerate the planets from the Sun Mercury Venus Earth Mars Jupiter Saturn and George and by the way that's the same George of the American Revolution George is it the George II maybe what which George was that thir third thank you good historian just calling that out that's the same George so I have we have Maps Planet George and no we're not calling it Planet George uh so here's Uranus okay so now watch what happens we look at the path of Uranus around the sun and it is not following Newton's Laws it's deviating it is not behaving according to the universal law of gravitation maybe we found the limit of Newton's Laws maybe they applied only out to Saturn and Uranus is beyond the limit people were considering this maybe we need a new theory of gravity to get us Beyond this all right some other people said Newton is a newton is badass B basically they whatever the equivalent of that word from 20 years ago that's the word they used okay this is John couch Adams farhead and this is Urbane leier these are two brilliant mathematicians this is from the UK obviously from France they said to themselves suppose Newton's law is not in error suppose there's another planet unaccounted for in our equations tugging on it that could explain it and leave Newton's Laws intact this is a very hard problem especially when you don't have a computer because you're not looking at the object and calculating a force of gravity at a distance that's just a simple formula you are asking yourself what would have to be here for have a force of gravity act in the way that gives you the perturbed orbit that's an inverted part of it's an inversion problem in gravitation and it took brilliant mathematicians to do it they each came up with these calculations then they sent it to Germany to Johan GA and on September 23rd 1846 the day after they he received these coordinates he went to the telescope they said look over here he looked over there and he found Neptune found Neptune exactly where it was supposed to be Newton's laws were intact uh I should not be showing you Uranus here this should be Neptune so Pretend This is Neptune okay okay so Neptune we got a new planet on our hands okay planet Neptune discovered by math and physics okay now we start tracking Neptune's orbit it's not following Newton's Laws by the way this these things take hundreds of years to go around the Sun so we're only observing pieces of its orbit there's uncertainties if you have only a tiny piece of the orbit you got to wait enough time to trust your data okay we look at Neptune and it's not following Newton's law well we've been down that road before there's another planet it's got to be and and thus was born the search for Planet X launched by pul LEL here he is looking very New England Tweety persful L he said there's got to be another planet out there they did the inverse calculation they couldn't find any Planet he say it's got to be there they checked the calculations again look here nothing there he says it's got to be there so he decided to search systematically across the sky rather than just in one spot well he would die in 1916 but the project had been started and was continued by the one and only Clyde Tomba he only died he died just before we opened the rose Center for Earth and space and that's a good thing because he discovered Pluto but did not live long enough to see Pluto demoted that's why I said maybe it was a good thing that he moved on Clyde tomow Farm Boy amateur astronomer built his own telescope he discovered Pluto how do you discover a planet you be systematic about it and then you take multiple pictures separate this is separated by a week and and so here's the same Starfield and right there in the center of that dot it moved to over there whereas every other object remain the same Pluto was discovered he was famous for saying when asked how did you find Pluto on the on the photographs and he said oh it was easy there was an arrow pointing towards it that was his big big joke okay so the New York Times reports on this discovery they give it a mass we hadn't measured a Mass for it yet but you know what Mass they gave it they gave it the mass it would need to have if it were disturbing the orbit of Neptune it was just handed a mass it wasn't measured that way and over time we continue to observe Pluto and it's like smaller than we thought and it's tinier it's got less mass than we thought and someone created a plot they said if this continues Pluto will disappear okay what's going on I'll tell you what's going on Planet X died in 1993 a paper published by mil SSH Jr that's the same name of one of the names that came over on the Mayflower Planet X no dynamical evidence from the optical observation here's what he noticed that the orbit for Neptune was obtained from many different observatories and you Cobble together the data from different time periods lay out the arc apply Newton's laws and you were not getting the right answer he said to himself wait a minute at the US Naval Observatory over that 10year period there's a swath of data and he checked like the log books and he found out that they did something like they they cleaned the gearbox they did something to the gearbox they did something in the log book and he said let me remove those data and keep all the rest when he did that Neptune landed right where it was supposed to be according to Newton's Laws so here we have a case of bad data so Newton's Laws fails the first time but then it's Triumph because we get the pl here it fails but not for that it had bad data what are you going to do okay let's keep going the planet Mercury closest to the Sun uh it has one of the most elliptical orbits of them all [Music] and if everything were normal it would just do this highly exaggerated it would just do this on the left but that's not what Mercury's orbit was doing that orbit is processing so for every Loop the the ellipse okay I've never before been in ellipse but this is actually kind of fun all right there's some force of gravity other than the sun that's making that happen we said we've been down that road before there's another planet there close close to the Sun you can't see it cuz it's always in the glare of the sun we even named the planet we called it Planet Vulcan we named it the astronomers were perfectly happy invoking another planet too close so during every solar eclipse where the Sun's light is blocked that we said do we see anything there none of the eclipses revealed a planet Vulcan so this was a conundrum but we weren't worried about it we just kept going then in 1916 Planet Vulcan dies it dies an ugly death because Albert Einstein publishes the theory of general relativity and in this we learn that under high gravity Newton's Laws fail they actually fail and it needed a new understanding of gravity brought to you by Albert Einstein in this research paper published in 1916 so here we are scientists trying to make discoveries and in the first case the failure became an affirmation of Newton's law of gravity in the second case the failure was because of bad data the theory still worked but it was bad data in the third case the failure was an actual failure we don't know this going into the problem we do the best we can yes things fail and the Press hardly ever talks about it so these are the kind of challenges we face and the book is all about that from the very first thoughts we had about about our place in the universe what went right what went wrong and by the way one of the strands as I said the DNA strands is pop culture so here's an example of Pop Culture when we talk about the density of things we talk about the Incredible Hulk okay uh there he is in case you don't know what he looks like so here's a here's a here's an interesting question uh because we talk about the density of air and what does it mean to float in air or sink within a so density is an issue so we talk about density in the Hulk movies are this are the scenery as you read through the book we whenever a topic is touched by a cinematic theme we'll go there so let's take a look so if you if you do the numbers the Hulk is about 10 times the volume of of Dr Banner okay well if you take Dr bammer and puff him up by a factor of 10 his density changes what happens to his density we're puffing him up yeah decreases it's the same mass but in a higher volume so let's see what the density of the Hulk would be okay so let's do this in grams per cubic Cent iron is eight rocks are three water is one by definition actually quk is2 the Hulk is 0.1 you could just kick the Hulk and he would just bounce down the road just see that c it be like a Macy's balloon you know just going moving down the street so so if he retained his density he has to get Mass from somewhere where's he getting the Mass from is he converting it out of the energy of the environment if he is he has to suck the energ because E equals MC squ had to suck the energy out of everything countywide all electricity would go out just for him to get the mass that he acquires just a little little things to think about as you're going through the book but my favorite Hulk is the credible Hulk okay so here he is the credible you won't like me when I'm angry cuz I always back up my rage with facts and documented [Applause] [Music] sources

Channel: StarTalk

Views: 496,433

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

Id: kaF2tq9zE-s

Length: 35min 54sec (2154 seconds)

Published: Thu Feb 29 2024