Why Planets Are Round

Why are planets round? Neil deGrasse Tyson and comedian Chuck Nice explain why the universe keeps creating spheres. What is so special about spheres?
We explore why soap bubbles, cold pigeons, planets, and the sun are all round. Learn about asteroid Ceres’ upgrade to dwarf planet and how Saturn got its rings. We also get into disks: why are some object spheres and other are disks?
Check out our second channel, @StarTalkPlus
Get the NEW StarTalk book, 'To Infinity and Beyond: A Journey of Cosmic Discovery' on Amazon: amzn.to/3PL0NFn
Support us on Patreon: / startalkradio
FOLLOW or SUBSCRIBE to StarTalk:
Twitter: / startalkradio
Facebook: / startalk
Instagram: / startalk
About StarTalk:
Science meets pop culture on StarTalk! Astrophysicist & Hayden Planetarium director Neil deGrasse Tyson, his comic co-hosts, guest celebrities & scientists discuss astronomy, physics, and everything else about life in the universe. Keep Looking Up!
#StarTalk #neildegrassetyson
00:00 - Introduction: The Universe Love Making Round Things
00:48 - Surface Tension in Soap Bubbles
2:34 - Why Birds Get Round
3:43 - Why Planets & Stars Are Spherical
6:25 - Ceres & Spheres in Zero Gravity
8:25 - How Planets Have Rings
10:09 - Galactic Disks

[@StarTalk]

Do you still believe in flat Earth?

[@pablohcm]

Never did 😎 ,,,Love from 🇯🇲

[@immunitycorrupts3641]

maybe an alternate universe but even then that's a stretch. but could there be such a universe? seeings how there could be infinite amounts. various accounts. what if gravity was stronger causing planets to be flat?

[@adolf4030]

Indeed ​@@rileynguyen8880

[@mrhomes204]

Well the earth is mostly covered in water, and that water is not carbonated, so technically it’s flat

[@bjchorny]

I thought it's a round planet on a flat universe

[@shelly_lee]

@2:56 that explains my weight gain in the winter months, i am just puffing up to stay warm

[@johnheath4305]

I stay fat in the summertime because I like air-conditioning

[@skellig5867]

😊

[@lemongavine]

You’re in perfect shape….round

[@AC-lt5ro]

🤣🤣🤣🤣

[@marisabella2650]

😂😂😂

[@melaninqueen6199]

“I can’t afford Cold Duck, I’m drinking Cold Pigeon”😂😂😂

[@LupeCoded]

That had me crying. 😂😂😂😂

[@michaelccopelandsr7120]

Still better than "Cold Turkey."

[@Chalepastel]

bbrrrrr

[@lemongavine]

😂😂😂

[@Kube_Dog]

You can tell a lot about someone's intelligence by what they find funny.

[@mikeplantagenet2983]

If the Earth was flat, cats would have pushed everything off it by now.

[@baymax8276]

woah😂😂 or should i say mewooaahhhh😹😹

[@joeburton9947]

3:25 Chuck made a perfect pigeon noise🐦‍⬛

[@markpashia7067]

Yup, so I ain't buying his comment that he never saw a pigeon.

[@apocbible]

New camera? Picture is sharp 👌

[@Mestizajee_]

That star talk money lol

[@Matt.Thompson.1976]

4K baby! Heck yeah!

[@Ryne4S]

When you’re so early that there are no angry flat earther’s unpopular comments around

[@a5cent]

Damn. They are the most entertaining part 😢

[@conradgittins4476]

Well, it's flat in places.

[@baconatorrodriguez4651]

Faaaake. Enjoy being sheep, rounders - them, probably

[@backstabingpike]

😂😂😂🦄

[@TheSilverShadow17]

When you're so early that you witnessed the formation of the Moon after Theia crashed into Earth.

[@pjcarrera2251]

The sun has badass gravity is a sentence I've never heard before lol

[@grisslebear]

That's how it can hold on to it's gas.

[@alswedgin9274]

imagine if it didn't..

[@alswedgin9274]

@@grisslebear and thaat gas creates gravity.

[@Kube_Dog]

@@alswedgin9274 Neil TheGas Tyson.

[@emersonberania3997]

Imagine Uranus if it didn't hold it gas😂😆

[@afrainaideentertainment]

God bless u Dr Tyson n chucks for the COMEDY, IT MAKES LEARNING EXTREMELY EASY N FUN! THANK U SIR! FROM NIGERIA!

[@HandMeDeals]

Does Chuck interrupting him constantly annoy you?

[@afrainaideentertainment]

@@HandMeDeals u dont know how learning works

[@zbynekvesely2613]

i love that after corona years, they are finally both in the same room :)

[@Kube_Dog]

It was inevitable. Tyson's extraordinary mass was bound to suck everything into it's gravity well. Soon Chuck will be absorbed into Tyson like a McDonald's breakfast biscuit.

[@AnonymousFreakYT]

The opposite of cold pigeon is "cat sunning itself" - stretched out as long as possible to maximize surface area-to-volume ratio.

[@forcingclimateinfo7014]

....! In underlying sentences Neil T have spoken about the earth's changes in a smart way for years in my head anyway. Thanks from Sweden!

[@STST]

I am an ex flat earther. I would LOVE the chance to talk with you Neil and Chuck. I've learned a lot since leaving the belief system of flat earth and gaining my trust back into science. From Dunning Kruger to Cognitive dissonance, to personal bias and tribalism. We have a LOT to talk about Startalk. Your own flat earth debunk is one of the most viewed videos on the channel. An actual chat on here with somebody that once believed the earth was flat would probably "break the internet" My email is in the description on my channel. Please get in touch 🙏

[@primonomeultimonome]

Hey @STST! If you get the chance, please tell Neil that the curve of the horizon is demonstrably detectable at much lower altitude than he declared in the past. 😉

[@gulfy09]

Your brain washed up

[@peterdarr383]

I met a FlatLander who pointed to a pond maybe 50 feet across and asked if it was curved or flat !! He was really fired up about Earth being flat.

[@Kobe8DaGreat24]

They don't talk to traders.

[@humbleevidenceaccepter7712]

@@peterdarr383 That pond was imperceptibly curved.

[@IansUToob57]

Flat Earthers are all around the globe. 😂

[@user-ce9dq7op9d]

What a punchline to such a remarkable joke😅

[@PostControlla]

Flat Earthers have StarTalk channel blocked because of comments like this lol

[@MrSamPhoenix]

At the very edge of the disk 💿

[@kcollo24]

dude 😂😂🙌🔥

[@bbuny10]

This comment amuses me ahaha!

[@ouronia1]

Dr. Tyson explains everything and anything so well. Love him.

[@josepht5331]

Today is my Friday… I think I’ll go get myself some ‘Cold Pigeon’ to celebrate the weekend 😂 🍾

[@CptnHowdy2475]

I am so happy someone finally gave the difference between spherical and round. I've been trying to tell people this for a while now and they always give me that WTF look!

[@JimmyOlsson]

Love these two talk! Always highly entertaining and highly educational!

[@ConductorK85]

God bless you, sir. You make understanding science simple. I wish teachers in my day had the intelligence and the integrity to explain things the way you do. I may have chosen a different path in life.

[@Kube_Dog]

Get up off your knees, worshipper.

[@wk4240]

These video sessions are great , great host and commentator.

[@alexlopez2439]

I love you guys! Perfect duo to educate. I wish I had both of ya in school teaching me. I would have loved going into this field!

[@BrickCityWill]

Also snowballs would have been a fun example to pack in there 😂

[@sandraf425]

the pigeon sounds chuck casually made 🐦🤣🤣🤣 gold 🤩 never change chuck

[@mr.t361]

Good one. Great expaining👏👏

[@derrickking7338]

Chuck and Tyson I njoy watching u 2

[@LaynoProd]

“is it big enough (mass & gravity) to be a sphere?”…THAT IS PROFOUND I CAN APPLY THAT WISDOM TO MANY AREAS OF LIFE THANK YOU NEIL 💎🤯🙏🏽 with gratitude, LaynoProd

[@user-js1bz7ev4g]

You are one of three persons i want to meet before they die in my life. Big Respect professor Neil deGrasse Tyson.

[@muggachase407]

For wat ?? Lol

[@whatabouttheearth]

​@@muggachase407 Why you bitter about life?

[@whatabouttheearth]

​@@muggachase407 Why you bitter about life?

[@muggachase407]

Nice try wrong guy

[@leeFbeatz]

What a fantastic episode! Although in regards to van Allen belt built light operabilities….. we need to chat, there is objectively deeper understanding 🙏❤️❤️🙏

[@marckonno]

I love to laugh and learn 😄 Thank you guys for providing such good content for years!

[@MaxHohenstaufen]

If soap bubbles wanna be round, cold pidgeons wanna be round, planets, stars, everything in the universe wanna be round, what's so damn wrong about my belly wanting to be round as well?

[@jennifersilves4195]

Not a thing.

[@Tydar]

Your belly is overcoming gravity. It's not in 0 G.

[@anthonybille4069]

I was eating a Bagel when I read this. I Feel you on that one, brother. 😂

[@mikepletka]

That’s a fair point my man I support you 😅

[@jmcota1964]

Great videos from you two!! I love your educational and entertaining content!!

[@user-vs6sv5yq1p]

I am enjoying my chance to catch each podcast , very educational ✊🏽❤️💯

[@DJ_DAV_iD]

Great new video quality 👌🏻

[@bipolarminddroppings]

The rebuttal to almost every Flerf "argument" is one word: Gravity. Why can't the world be flat? Gravity. Why doesn't the atmosphere fly away? Gravity. Why don't we get flung off into space by the spinning Earth? Gravity. Desertphile did the world a favour with his famous youtube clip!

[@jennifersilves4195]

You obviously don't understand how gravity works. 😉

[@ericgolightly8450]

​@@jennifersilves4195I don't really care if what you said is wrong, what does the winking emoji mean?

[@whatabouttheearth]

The problem is that most flat earthers deny the existence of gravity and space

[@whatabouttheearth]

The problem is that most flat earthers deny the existence of gravity and space

[@metalzonemt-2]

I'm not fat, it's just the forces in the universe conspiring against me.😎

[@whatabouttheearth]

🤔 Lipids are hydrophobic and naturally turn into spheres in water. Cell membranes are lipids. This is how the first cells originated in water. We are made of cells. We are all fat.

[@whatabouttheearth]

🤔 Lipids are hydrophobic and naturally turn into spheres in water. Cell membranes are lipids. This is how the first cells originated in water. We are made of cells. We are all fat.

[@dawnhansen7886]

Educational Entertainment to the MAX ❕️I Love StarTalk ❤

[@tanadarko6991]

I love this stuff. I wondered at this during the solar eclipse I witnessed a few years ago - but the explanation is so much simpler than I imagined it would be!

[@jameslightell13]

I have a question: one that is often taken for granted. If space has finite dimensions and everything in the universe is within this space, what is keeping all objects in space from falling to the bottom of space if any thing? Are celestial bodies free-falling or is there something keeping them suspended / buoyant? Is there a way to even test this given our perspective as observers in the universe? I hope you can answer.

[@TheMR-777]

Not an expert :), but I think that's what is referred to as Dark matter, and Dark energy.

[@Brand_One]

You guys get a new camera? Looks really good.

[@jaymiller2268]

I have been wondering why planets are round for a while now, so this was super exciting to see come out & then watch. Thank you for the always great educational content.

[@JSSTyger]

These guys are so well rounded.

[@maxwell4546]

Have fun. :) I freaking love Chuck.

[@Kube_Dog]

Please... he's the absolute worst on multiple levels.

[@therewillbecatswithgwenhwyfar]

Team Pluto!❤😂

[@Kube_Dog]

Tyson has recently exceeded the mass and circumference of Pluto. We should petition him to be named the new ninth planet.

[@PaulSinnema]

I like the physics. I’m just a dude listening in and loving what you teach me. Thanks Neil (and Chuck).

[@jointheleanrat]

The SLO Mo Guys and cold pigeon... Great piece! ❤

[@DunwellAntwi]

I love the way Star Trek gets most of the facts straight. 🖖🖖🖖

[@gulfy09]

Fake world you live in

[@ScoobyYTP]

Forces pulling in all directions to create spherical object. Nice and self-explanatory, a five year old can understand it. A comprehensive example would be a bubble in a bath. It is spherical because of the balance of forces acting on the thin film of liquid surrounding the gas inside.

[@KoRntech]

You've clearly not had the pleasure of reading Flat Earth Friends and such comments, if you value your sanity don't but if you dare glance just be prepared to figure out where we went wrong in society. 😐

[@AfrikanGod1]

Always fantastic Dr Neil!! Thank you for the Knowledge

[@Wis_Dom]

Thanks Neil and Chuck. That was great, informative and funny!

[@peterlyall6789]

This Star Talk episode was very good in a roundabout way.

[@frogz]

it's easy to make a cubic soap bubble, you just need 9 others to pull it into shape, or a wire frame

[@michaelhennaut3141]

Need 6 bubbles. A cube has 6 sides not 9. And it's not a true cube because of round sides.

[@jasonyoung7705]

@@michaelhennaut3141 A square (well cube) bubble was made on the program QI. it took a wire frame, which had bubbles pressing on other bubbles, to flatten the sides (well thats how it looked)

[@markl3893]

kzbin.info5PTL5N5c4jc?si=8wDdK9i3DxK7EQuK

[@fldon2306]

Seen photos of a square bubble!

[@alswedgin9274]

multiple bubbles competing to create the illusion of 1 bubble that has the shape you want...

[@wolfeddie]

Man, i enjoyed this episode! 👏👏👏

[@Yahweh4ever]

Wow these videos are so interesting!

[@mindblown42069]

Why are galaxies disc shaped? Should they not be more round also?

[@sketcher2459]

Difference in scale and angular momentum

[@kangarune]

That's orbit. Most orbits are on a plain. There are galaxies that aren't so organized though

[@espenstoro]

Lots of them are elliptical or round.

[@monkerud2108]

something cool about liquid in orbit, is that as you make them larger, the less the surface tension is able to hold it together in a sphere, and the larger you make it, the more powerful in relation to surface tension the tidal forces become, and so you should eventually be able to see the tidal force on a large enough blob. see is a bit of an exaggeration :P

[@alswedgin9274]

like an ac next to a soap bubble.

[@peterdarr383]

The ISS is only about 13 feet across at most. Not big enough to see an elongation of a water bubble ?? And that would be like ALL the water up there !!

[@rezzokii8080]

❤Learning something new everyday 😊 and more knowledge to know 😅

[@Romamb]

Fabulous education.

[@ZeroIQ2]

it's actually shocking how many flerfs (flat Earthers) there are

[@actyon20]

Loved it, the background, the jokes, you Neil and Lil Chuck . God bless!

[@MaskedBishop]

We will always love you, Pluto! ❤

[@sbloome77]

Love the educational content ❤

[@JohnB1163]

If you have watched the astronauts on the ISS playing with water you should have noticed that in the zero gravity that water floating in the air takes on a spherical shape which by the way is actually it's natural shape

[@ziegweid]

Surface area/volume efficiency 😂

[@JohnB1163]

@@ziegweid Exactly, and what will it do in a gravity field? In a gravity field it will take the shape of the container that holds it or if not contained it will go to the lowest possible point it can get to

[@gulfy09]

How can anyone drink or eat anything

[@JohnB1163]

@@gulfy09 They have specialty containers and specific foods for the astronauts so that they can still get proper nutrition and stay hydrated in the zero gravity of space while also keeping them and the ISS safe

[@yourguard4]

@@gulfy09 gravity is not required for drinking/eating. You can swallow even when standing on your head.

[@Marvelomarv]

Fruits being in spherical shape.......meanwhile, the banana is just a rebel 😂😂😂

[@Asia-yy1kh]

I've learned so much

[@kirandeepchakraborty7921]

Nothing short of brilliant ✨

[@uwu-ed7nn]

Question , if you had a lazer in space , would ot shine all the way until it hit something ? Or would it fade out?

[@ericgolightly8450]

If the photons in the laser are all parallel, it would shine until it hit something.

[@ayezz2811]

You know I really can not genuinely fathom the fact that there are people out there who truly believe it’s flat These replies are out of hand man yall need school 😭😭

[@gulfy09]

Keep believing NASA

[@primonomeultimonome]

@@gulfy09 Get an education.

[@qkqk6954]

Have you seen the globe proof on the series genius by stephen hawking?

[@gulfy09]

@@qkqk6954 tv crap nope... they feed your mind with stupidity

[@gulfy09]

@@primonomeultimonome wake up space is just nonsense

[@EarlyB_sa]

Love from the mother land South Africa❤ i really enjoy watching this channel real fun way to learn and laugh😂

[@deolihp]

This is really interesting

[@michaelccopelandsr7120]

Disclaimer and Trigger warning: This video contains copious amounts of truth and common sense. These values have been found to break what ever flat-earthers use to think with.

[@GregMerritt-ws8tq]

I've literally survived hypothermia by getting as round as possible.

[@jeremycraft8452]

That’s my overall strategy for avoiding hypothermia altogether.

[@GregMerritt-ws8tq]

@@jeremycraft8452 I imagine there's a possibility that's ingrained on us on an instinctual level even.

[@stevend.bumgarner6134]

When the conquistadors first traveled around the tip of Argentina, they met natives who were much larger than them who lived in the frozen lands of Patagonia, wore little clothes and kept themselves warm by crouching into a tight ball.

[@sapelesteve]

I must say Neil & Chuck that that was a really round about way of explaining roundness! 👍👍🤔🤔

[@AngelinaCruz357]

Your videos 📹 are truly inspirational ❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤

[@kevinfletcher1999]

I’ve seen a square bubble. Stephen Fry made one on QI.

[@michaelallen2358]

Chuck and NDT 4 president and vice President.

[@rayg.2549]

Let's get that campaign started!!!! 🥹🇺🇸

[@alexanderpaul352]

Too young

[@i.o957]

He would be the worst president in the history of the us. Too full of himself

[@entropytheory8875]

@@i.o957I like NDT but totally agree lol

[@PlutosMoon22]

Glad to hear Pluto's Moon mentioned ☺️

[@HughJass-jv2lt]

Star Trek *UNDISCOVERED COUNTRY* 😎😎

[@brentlee1043]

Question: Does that make the Earths Moon a dwarf Planet also.

[@sketcher2459]

Three reasons the earths moon isn't a dwarf planet. 1. It orbits our planet. 2. Much smaller than dwarf planets. 3. Not in hydrostatic equilibrium (enough mass for its self-gravity to pull it into a roughly spherical shape)

[@DrMeikoHayakawa]

Earth's moon cannot be a dwarf planet cuz moon is under the Earth's gravitational influence. There are 3 criterion for any object to be considered a planet: 1)The object must orbit the Sun. 2)The object must be spherical in shape due to its own gravity. 3)The object must have cleared its orbit of other debris. For Pluto which is a dwarf planet it orbits sun, and has enough gravity to be spherical, but lacks the gravity required to clear and accumulate all the debris into itself. -Moon orbits earth.

[@NickLavic]

​@@sketcher24591. True 2. Our moon is actually unusually large. It is larger than Ceres and Pluto combined. 3. The moon is spherical.

[@davidt3956]

Yes. It's one reason astrologers such as Tyson rejected the committee's definition of a planet.

[@AdH104]

The Moon is much smaller than dwarf planets? How can you say that when you look at the following examples? Diameter relative to the Moon; Pluto 68% Eris 67% Haumea =45% Makemake 41% Gonggong 35% Charon 35% Quaoar 32% Ceres 27% Orcus 26% Sedna 26% Salacia 24% The Moon doesn’t orbit the Sun independently, the same goes for any of the Moons in the Solar System, anything is officially a Moon when it orbits a planet. Pluto is a dwarf planet but if it was within Earths gravitational field it would no longer be a dwarf planet, it would be a Moon

[@jtgullickson6117]

Chuck Nice, you are a rockstar🔥 love you man!! Keep making Startalk your jam!!

[@gralant22]

Great episode! Please let me ask, does a spining black hole flatten out as well as any other objeft?

[@gralant22]

Oh nevermind, at the end i got my answer😅

[@mikeuk666]

The disc around it does

[@lukasmusinskas1951]

Love this channel

[@lovelywaz]

All the Flat Earthers got triggered by the title and that thumbnail pic.... 🤣🤣🤣🤣

[@ukdnbmarsh]

some flat minded folks just dont understand the gravity of the situation

[@centaur7607]

😂

[@DaraGaming42]

Neil Just had to get them Round to this typE of thinking , this is science on a global scale

[@deloreangreen358]

Funny and educational 😂 love it

[@Nefville]

I'll never unsee Saturn as being partially flattened now, a spheroid. I knew it was but I never noticed it in images of Saturn. Very cool.

[@The_Nonchalant_Shallot]

Flat Earth Society would like to know your location.

[@ray1956]

😂😂😂😂😂

[@londonmmc]

Near the edge of the

[@tysonleyba430]

maybe in 4D or 5D were actually flat haha

[@johnVidBozo]

Neil is great by himself but Chuck takes it to another level. I think it's time for a shot of cold pigeon!

[@KoppanyE]

I have seen a cube shaped soap bubble. OK, it was surrounded by several bubbles, but still it looked cool. 😊

[@derrickking7338]

1st comet….GET IT….??😅

[@rosecityusa6120]

I do actually. 🥱

[@DXARMY4LIFE]

Atta boy

[@biglebonski]

Can you guys please do an episode on the potential need to revise our current understanding of the universe based on recent observations? It seems only a matter of time before we have to conclude the universe is much older than we now think. Thank you!

[@antialluvion5118]

Relativity question. If I were to go the speed of light, time stops for me relative to people who are going slower than me. But what would happen if I were to oscillate in basically the same position in space but oscillate at the speed of light? Would time stop for me in this situation also? I'm not really thinking about an object like myself but I was thinking about all the subatomic particles. From quarks to electrons, All of these things are energy that I imagine is never sitting in a state of stillness. And it is always moving then I would assume it would move at the speed of light regardless of whether it was traveling across great distances or in a stable position in space by oscillating or something like that. So I was just thinking that if this was true then the very things that form all matter are essentially not moving in time and we are all constructed of this material which would almost suggest that in some regards we aren't moving in time... Or it could be the case that the energies that make us aren't moving in time but collectively as more macro objects the macro object can move through time even though it's constituent parts don't move through time because they oscalate at the speed of light? Absolutely nobody is going to answer this. And I can't find anything on Google about this. I'm sure it's ridiculous but would love to satisfy the curiosity if somebody with expertise in this area could provide some insight

[@BGTats144]

LMAO my twin brother is a flat earther and says Neil deGrasse Tyson is a globe earth priest WTF...he literally thinks globe earth is a religion..

[@johnheath4305]

I really like y’all in the same room

[@riteshchaubey8660]

Love from India❤😊

[@AK_14564]

Chuck looks like his been through something tough, i hope you are alright man, we love ya Great video as always

[@robelmichael2962]

Nice one

[@aggielonghorn]

Competing forces are amazing to ponder. Immovable object vs irresistible force is probably not a thing. One force would prevail.

[@tayyabnaseer1]

Kindly add subtitles as well

[@depaykaris486]

love you guys