Why is the Earth Round and the Milky Way Flat? | Space Time | PBS Digital Studios
Why is the Earth round and the Milky Way flat

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Let PBS know what type of digital series you'd like to see by taking this survey: https://www.surveymonkey.com/r/pbsds2016 Why does our universe make spheres and disks? Get your own Space Time t-shirt at http://bit.ly/1QlzoBi Tweet at us! @pbsspacetime Facebook: facebook.com/pbsspacetime Email us! pbsspacetime [at] gmail [dot] com Comment on Reddit: http://www.reddit.com/r/pbsspacetime Our universe is not a very diverse place when it comes to shapes. Large celestial bodies become spheres, galaxies become discs, and there is little room for variation. Why is this? Well it turns out physics has some pretty strict rules when it comes to creating new planetary bodies. On this week's Space Time, we explore equillibrium and symmetry, the two defining factors that shape our universe. _____________________ COMMENTS: Felix Ironfist https://www.youtube.com/watch?v=JDmKLXVFJzk&lc=z12dwzk4iquld5g0323uivizxm2xxxdk2 Florent POUJOL https://www.youtube.com/watch?v=JDmKLXVFJzk&lc=z13pcn3rgpzxexgym04cfbeokpeaspzidjw Reuben Silva https://www.youtube.com/watch?v=JDmKLXVFJzk&lc=z12bcv4w0muzd3ihm04cchbp0s3kyjpj3p00k Dom Vasta https://www.youtube.com/watch?v=JDmKLXVFJzk&lc=z13ns1kqdw2kf5bzm04ccd4arybjvvvgcow0k ______________________ Written and hosted by Matt O'Dowd Made by Kornhaber Brown (www.kornhaberbrown.com)


Cyramor11 : *watches video* You have gained 20 IQ points! *reads comments* You have lost 30 IQ points!

dylanstosz : "Why is science a verb now? Because I verbed it." 10/10 great pun would wordplay again.

Lynard Ramos : born too late to explore the earth born too early to explore the space born just in time to witness the golden age of waifu lol

Ponlets : 144 people are flat earthers who think everything is disk shaped :P

khatack : "Because I verbed it" xD Simply brilliant ^^

BIll Geo : "Because I verbed it"!!!!!!!!!!!! Epic! Also messed opportunity to put sunglasses and "deal with it" on top!

Daniel Hviid : I already know these things, but hearing Tyrion Lannister explain them is just relaxing.

Rex Galilae : I hate to say this but you guys have made minute physics obsolete. Henry Reich tries to compress videos on mindblowing topics to a few minutes and speaks as though he's about to catch a train. I watched a video on the same topic on his video but ended up understanding nothing. I appreciate your emphasis on clarity rather than time. Keep up the great work!!

Anna Corcoran : Spheres: Shaped like meatballs Disks: Shaped like plates Flying Spaghetti Monster confirmed

Simo Asri : I can't stop watching videos of this channel lol whole day watching literally, since I woke up at 7am it's 7pm now and still watching

Nikolay Yakimov : Um. 8:00, while you say '0.03 m/s²', video actually shows 0.3 m/s².

Bubble Tea : Oh boy, the flat earthers are really gonna hate on this video.

BlazePlayz YT : Nobody: Flat Earthers: Earth is flat and the Milky Way is a sphere.

Tom Dickinson : 9:55: Medium beard 9:57: Short beard.. Damn Matt, you sure change fast!

The Iguana : What if in the distance future the word "minecraft" just means 1x1 meter cubed? And people just forget that it was once some videogame?

Toma Tom : I get how the 2 shapes come together, but the key question is: why do things spin? At 8:57 u say they start out slowly, but why do they spin in the first place?

H I D E O V T : Milky Way is flat because that way it's easier for the turtle to hold it on its back, duh...

David Awakim : that guy has an awesome voice :)

Skepticat : "Why is science a verb now?" "Because I verbed it." * drops mic *

cragnog : Im starting to notice how every once in a while, you'll sound totally American for the length of one word, and go back to your usual accent. Examples... 2:15 ("Here"), 2:46 ("Sphere"), 3:12 ("Sphere" again..), 3:48 ("There" yeah there's a pattern to these), 3:57 ("Pressure" breaks the pattern!!!).... and maybe more

Badly Drawn Turtle : When asking about the limits of science, it's important to remember that science and reason are only tools. They help us answer questions, but they cannot ask the questions for us; this is especially important when asking about the application of science in ethics. A scientific study of ethics is quite possible, but without first telling the tool what you want to know, it's lost. For example, you might have 8 slices of pizza, and five hungry friends; you can use reason to distribute those slices fairly, but you have to define ‘fairly’ outside of the realm of reason. Reason itself doesn't care if one person gets all of the slices, or if they go in the garbage uneaten; you have to tell it what your goal is.

jon burford : Don't let the flat earthers hear you say the earth is a sphere. Their heads with explode do to an overwhelming input of legitimate evidence based information.

Aric Majere : If we were able to instantly transmit matter, via teleportation of some sort, would physics cause an explosion due to the sudden removal of an object from a system of mutual force? You were showing the pressure earth exerts on surrounding earth. If we teleport a significant portion of the surface would the matter pushing back up on it suddenly fill that void? I am already aware hypothetical teleportation would cause gas to collapse into the void with a sonic boom; similar to lightning and thunder. I apologize if this is not worded well. #notascientist

Kelvin Guifarro : Are the possibilities to viewing a square planet, Real?? And Will there be "LIfe" in Such A Mega-ton Phenomena?

BorlandC452 : That was really interesting, but what causes the axis to form in the first place?

Red Berry : Epic ending hahahahahaha xD

BB B : When your beard breaks the causality principle

Jake's Dad : I was about say, hey this is a channel for smart people, there won't be any idiots saying first.... I guess I'm wrong...

Shreyas Misra : But. ..but..the earth I'd flat!! its held up on the back of four elephants standing on a turtle!

Michael : You guys seem to love your general relativity (hey no judging Eisenstein is really cool) but i was wondering if you could do some videos on quantum theory. Perhaps discussing things like quantum tunneling or the possible formation of a Boltzmann brain.

Wyse Solomon : But I thought the Earth wasn't a perfect sphere

B FN : What if the current model was wrong and it's actually round, tho? By the way, it's just an assumption. But, what if?

Shirley Mason : The planet Earth is indeed flat...as in “flat,” for I have visited some of its edges and I can assure you all that the good citizens who dwell near the edge are extremely nervous and edgy. Children who don’t mind their elders disappear over (or around) the edge. And I shudder to recall a few people who have lost an arm, or a leg, when they stuck that limb over the edge (kind of like one would test the water) only to find there was nothing to pull back. On into the night citizens discuss just what causes arms or legs to vaporize, as it were, into nothing. Some say it’s the radiation, that once off the flat Earth platform, there’s no flat Earth shield. Others swear that the Devil’s domain is over the edge, and that he or she feeds on stray arms and legs. While there (in Edge Village) I was directed to a Utube video describing how a prominent scientist insisted in being dangled by rope over the edge, and was never seen again. It was said that as he sank off, his last words were, “Ohhhhh shiiiiiit” ! Some say, that instead of evaporating, whatever is lost over the edge becomes a permanent fixture attached to the side. After all Earth has volume whether flat or nor, and the gravity of its sides is unyielding. I tried to bring some citizens back with me to a safer, central location, but so many of them were tethered together so no one could slip off, that it proved hard to find loose ones willing to travel. It seems to be quite true that the devil you know is the devil you love. Oh, and by the way, universally...flat Earthers have rather...or quite...or very....flat heads due to gravity attracting equally across, rather than angling toward a central core. Well, that’s how some one put it to me.

Zahven : The earth is definitely not round... ITS FLAT LAJDJSJNZKWKDJCJSOS

Austin T : "Why is 'science' a verb now?" "Because I 'verbed' it." 1. You are a genius. 2. I assed my laugh off. Thank you! I shall now refer to this and make a joke out of it. Kudos!

DarkRenaissance2012 : 1980s = Contests,, skill and creativity 2000s = Random drawings of pure chance

Tyson Adams : So because of pressure it IS turtles all the way down!

Noriel Sylvire : Here's my hypothesis (before watching the video): The earth is a solid object, and gravity pulls it inward from every direction. However the galaxy is a lot more loosely packed and is composed by a lot of more empty space, so it could be thought of as a spinning gas. The centrifugal force isn't powerful enough to deform solid earth so much that it stops looking like a sphere, however it can deform our gas-like galaxy, and indeed does. So that's the end of the hypothesis, now comes speculation. Also, there are galaxies that do look more spherical, and I don't really know cause I'm no astronomer but that could be because they spin slower than our galaxy.

Comfy Man : Matt O'Dowd has what I believe should be the universal voice of knowledge. Degrasse Tyson should be the universal voice of curiosity.

bakkels : "Because I verbed it!" Damn, that got a genuine chuckle out of me.

Jane Stewart : "because I verbed it" Fight the power man! I'll science whatever I damn well please!!!

Carlton Galloway : earth is a flat disc and the milky way is a sphere

Mogalize : Gotcha... Spheres happen when pressure is the dominant effect resisting gravity. Pressure is spherically symmetric. Discs happen when orbital motion dominates the resistance to gravity that’s a circularly symmetrical effect and so you get, well, a circle. Round Earth guys: 1 Flat Earth Guys: 0

Stermy Swinters : 2 things! Milky way is a universe and its very big Earth its small so on the milky way u cant barely see earth cuz its so small

Marcin Lysakowski : Matt, you are a freekin' champion. Thanks for the video!

The deathless face of the unborn mind. : I swear I have a quasi-spiritual experience watching these videos.

Shashwat Tiwari : thankyou for giving this kind of knowledge in Astro physic it's really helpful for me to know about space and time and their coordination

Rudie Punk : Amazing show! You're the best, keep it up!

Samuel J. Rivard : how i understand why my fart are spiralling in a disk form... :p lol nice video btw!!!