Neil deGrasse Tyson Explains Why Science Is Hard

[Music] yes i'm back i know you got something else i know you got to have something good you got a few minutes i got a minute or two okay i want to spend just a few minutes talking about why science is hard okay so you spend your whole life trying to get people to get into science this morning you wake up and you go you know what forget all that let's just tell them the truth let's tell them science is hard and drive them where they belong well i don't i don't think you're going to surprise anybody with science is hard but hard in a way that maybe you hadn't fully appreciated okay now that okay once again you've been treated you've intrigued me all right now you've intrigued me in the physical sciences especially physics astrophysics this sort of thing you need a tandem background in math and many people don't like math so for them science might be hard simply because it has math right so but i'm gonna i'm gonna go someplace completely different oh okay oh okay now i'm now i'm really i'll tell you why it's hard because guess what the thing you just said was enough for me okay you had me at math okay all right so here's why okay and this is going to be storytelling excellent storytelling all right so back in the 1700s late 1700s there was an astronomer named william herschel uh he was wealthy you know had access to great telescopes and he liked looking up herschel personally all right um he discovered an object that moved against the background stars okay cool and people have discovered such objects before they were all comets okay all right if something's moving and it's a comet so he kept studying it and he and if you read his research papers it was odd comet that this is it's not showing any fuzz that's a peculiar comment i wonder when it will start showing fuzz and he goes on and on and on about this account of an unusual comet he discovered the planet uranus oh wow and you know why he was in denial because no one had discovered a planet before right right it was an act without precedent all right all the known planets mercury venus mars jupiter and saturn these are the planets in the sky of the earth all of them were known since the ancients and they're bright enough cavemen would have seen it so no one had to that was they were not from the act any act of discovery because they're all brighter than the naked eye limit in the nighttime sky so uranus was the first planet to be discovered and it required a telescope and he was in denial of it because it had no precedent so first the scientist is challenged by discovering something for which there is no precedent hmm what do you call it how do you think about it what do you he didn't say oh i discovered a new plan he said i discovered a weird comet right so he discovers it he realizes it's a new planet this is big news international news and what do you do oh he's a brit uh by this is late 1700's so there's king george this is the same king george of the declaration of independence to whom it was written right okay yes and so he named it after the king ah so for and i have textbooks from this period of time after that planet was named but before it got renamed for a while there the enumeration of planets was mercury venus earth mars jupiter saturn and george stop it serious come on you want to keep the king happy the man you know you can't bl don't blame right listen you can't piss off the king i saw him i saw hamilton i saw hamilton i know you don't want to mess with king george all right let's have this it's the same king right okay so that lasted a few decades until clearer heads prevailed it's in a waiter it's a planet and how are the previous ones named well they have roman name roman gods right uranus is kind of both greek and roman so there it is so it got named damn that is unfortunate okay do you want it you wanted a planet george i swear to god it would be so great we are launching a probe to planet george or it would be fun it would approach to freddy you know just your name no because maybe that would have started a precedent where you just start naming stuff like you know what i mean and comets get named after people like you were like haley haley's comments exactly okay all right so now here we go i'm not done yet go ahead so you track the orbit of uranus and you find out it's not following newton's laws of gravity and newton's laws have been known for 100 years by then okay and so people said hmm maybe we found the outer limits of where newton's gravity applies ah because it worked between earth and the moon earth and the sun the moons of jupiter everything that was orbiting somebody else that we observed that newton's laws were bang on but let's go farther out in the solar system here we are at the farthest most planet uranus and it's deviating from where newton's law is predicted so you say all right do we need a new law of gravity no newton's been working pretty well lately a new one to extend newton's laws because it doesn't apply that far out maybe it only works in our own solar system you don't know this in advance okay people have to figure this out so they say all right um maybe newton's laws do apply at uranus but there's another planet out there that we haven't discovered yet that's tugging on it and we didn't put that in the equation so so maybe uranus newton's laws are correct and uranus is being touched by yet another planet so here we have a situation where all right if there's another planet how are we going to figure out where it is right this is an extremely difficult math problem it's one thing to have an object invoke newton's law of gravity and say here's the strength of gravity at this distance from you okay it's different to say here i am responding to a force of gravity out there and i don't know how strong it is and i don't know where it is so it's a mathematical inversion problem of that gravity of the gravitational setup and so two brilliant mathematicians took their to took their genius to this and one of them is is french right and another guy named uh john couch adams okay and i think he was a brit and so brilliant mathematicians they did this inversion problem and le verrier got there first and he said hmm if newton's laws apply and there's something tugging on it it should be a an object over here in this part of the sky okay so he he he got the message to the berlin observatory and there's a guy named johann gal who the night he the day he received that note that night he looked where he was supposed to and found the planet neptune holy crap it was just a triumph of newton's laws of gravity a triumph of mathematics a triumph of international communication and cooperation and there it was planet that's amazing totally amazing and it's a beautiful story too it's beautiful all right so now we have planet neptune and all right we're good pat ourselves on the shoulder then you say all right so something's happening with neptune something's happening neptune and also parts of uranus were not collectively were not following newton's laws precisely so well we've been down that road before right come on we even know what's going on time for another trial time for another planet okay exactly so let's perform the math it's a planet x okay famous planet x so let's do the inversion problem and look over there nope no planet okay maybe i didn't do that right let's look over there nope no planet so we're right now up into the late 1800s early 1900s and percival of the new england lowells around who was uh not to be not to be confused with the north carolina rules the personal uh uh he built a telescope put it on a mountaintop in arizona where there hardly any cloud so he knew what he was doing and he um he said i'm gonna find planet x okay except he died before that happened but by fortunately he hired someone who took on this task and that was clyde tombaugh a young amateur astronomer who was hired to say all right forget this inversion math problem looking in spots in the sky let's just look at the whole damn sky okay let's do let's just be systematic about that so clyde tombaugh systematically photograph the entire sky in the plane of the solar system okay where you find all the other planets he just just systematically photographed and did it twice so you do it twice so that you compare the two and if something moved it it shifts from one picture to the next right because i got something okay that's so cool they still do that today they don't do that today they do yeah computers but we still do that today right and with the human eye brain combination is very good at noting noticing something different all right between the pictures i have a whole book of those puzzles excellent excellent so much fun excellent so so you still haven't grown up right yeah you know you know what's the chuck put down the where's waldo books put it down away from the book [Laughter] so go ahead so he does this and so they find a lot of things in this survey they found asteroids they found what okay and then then 1930 there's the announcement we have found planet x and it got to be called pluto clyde tombow in 1930 discovered pluto wow all right so now the new york times headline said planet x found we expect it to be the size of the earth because that's how much mass it would need to jiggle on on neptune on uranus and neptune okay all right so then over the years however people kept trying to measure the size of pluto and no it's not as big as you thought no it's not as massive as you thought no it's even smaller than that no it's even smaller than that in fact over the decades the estimated size of pluto kept getting smaller and smaller and smaller someone created a chart to see if we keep this up pluto will disappear in the year 20 right because estimates kept getting smaller and smaller for the size of pluto it became completely clear that pluto did not have the chops to be responsible for the perturbations on uranus and neptune [Music] wait a minute let's let's let's not forget that part of history where neil degrasse tyson comes along and then pluto is just dissed and demoted and implicating me i was an accessory first of all and this explainer video ain't got nothing to do with that okay so don't be dragging that in and making people angry on the comment thread chuck i thought you were my friend [Laughter] without having to be historically complete okay okay go ahead planet x was not really there that pluto was was not solving the planet x problem right okay plus we had looked where the mathematician said it should be and it wasn't and pluto was found somewhere else but the excitement of having found planet x carried the day okay it still didn't solve the uranus neptune problem it took till 1993. oh my god okay and what do we have by then we have excellent mass measurements for uranus and neptune from the from the voyager flybys we have excellent mass measures of of other objects pluto's mask as better known and so we know more about the mass tugging that's going on in the outer solar system and a guy named miles standish jr working for the jet propulsion lab said let me try to resolve this once and for all so he looks at the orbits of uranus and neptune it looks at how much they're being perturbed and said well we looked there we didn't find anything well let me go back to the data and here's what he found that between 1895 and 1905 the u.s naval observatory that's in right outside of dc might be in dc the us naval observatory had a set of data on the orbits of uranus and neptune that were kind of different from other data that was out there and then he wondered well did they clean the gearbox over that time does something different happen there or did it get gunked up so he said let me just excise that 10 years of data from that observatory from this analysis when he did that all other orbital data from all other historical telescopes fell right into place and boom planet x evaporated overnight oh my god so he killed planet x he killed planet x by discovering faulty data right so all the other data lined up because that data was twerking the other data right twerking not twerking twerking it torquing the other data if you're trying to fit it and something's tugging on it and you think something's tugging on it when in fact it was just simply bad data and then milestones had the right wherewithal he's a scientist right to say let me see what happens if i remove it and he does it all planets line up newton's laws are intact there is no planet x all is well in mudville that is amazing so the first time it's if herschel thinks it's a comic second time it's the triumph of newton's laws right third time it's faulty data right okay and you don't know any of this advance you just sort of you're wandering in the dark because you're at the limits of human understanding of the universe but wait my story is not over uh oh what happens in the late 1800s we're looking at mercury's orbit and mercury now okay and we find out that you know it's an ellipse and the ellipse is not staying stationary in space it's actually the ellipse itself is rotating so in other words there's mercury going around the sun and there's a closest point to the sun you wait till the next orbit that closest point has actually rotated a little bit okay the closest point rotated again so the ellipse is actually dancing around the sun in a way that cannot be accounted for by newton's laws can't explain it well we've been down that road before right it's a it's a planet okay where's my standards when you need them okay no no but then that would be the errors right so we had good enough data we know there were no errors in these measurements oh that's right okay okay so what could be causing this it's got to be a planet come on we're we we're experienced at this well how come we haven't discovered it yet it should be right in front of our nose well because it's it's orbiting really near the sun and it's so near the sun it's blotted out by the sunlight but it's tugging on mercury preventing mercury from following newton's law so we astronomers were perfectly happy with this we even had a name for that planet it's called vulcan okay so planet vulcan was in the books we hadn't discovered it yet but we knew it had to be there just the same way your neptune was in the dark skies of uranus okay and there we were then we said well if it's there and the sun is too bright let's look during an eclipse right okay so every eclipse that came up everyone comb the sky around the clips no vulcan no vocal they said well maybe was behind the sun for every one of your eclipses i don't think so i don't know okay so you know what happens 1916 happens albert einstein invents discovers the general theory of relativity which is an extension of newton's laws of gravity for very high sources of gravity such as if you're near the sun and what he discovered is that this procession of mercury falls right out of his equations yes newton got it wrong in the presence of high gravity his laws fail and it required the new and improved understanding of gravity brought to us by by uh that's right the moral to the story is math is hard sciences science is hard in one case it's it's the laws are correct and you make a prediction in another case the law is still correct but there was bad data in another case the law is wrong and you need a whole other theory of physics to explain it i'm just trying to get you to understand and appreciate appreciate it no i love it because and here's i know we're over time but i just got to say this the beauty of this story is science is a journey it is not a destination yes and at all times at all times it's a journey and you got to be open to any possibility you got to be open to the possibility that your comment might be a planet that no one has ever discovered before you got to be open to the possibility that somebody's data sucks you gotta be open to the possibility that the power of your math and laws of physics are genuine and can actually extend your understanding of the universe and you gotta be open to the fact that you might have already reached the limits of the applicability of your theories and laws and you need a whole new one such as what einstein put on the table and chuck that's why science is hard sweet we gotta cut it quits there ah okay all right this has been the science is hard explainer chuck always good to have you always a pleasure to be here as always you

Channel: StarTalk

Views: 320,649

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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, Chuck Nice, science is hard, Uranus, Neptune, Pluto, scientific study, comet, planet, William Herschel, George, Plabet Vulcan, Planet X

Id: w8PoG3mvqk8

Length: 19min 56sec (1196 seconds)

Published: Tue Sep 29 2020