Neil deGrasse Tyson Explains Colliding Galaxies in an Expanding Universe

If we live in an expanding universe, how can galaxies collide with each other? Watch Neil deGrasse Tyson answer this fan's Cosmic Query, in addition to addressing comic co-host Eugene Mirman's concerns about our Milky Way galaxy's impending collision with the Andromeda Galaxy in about 6-8 billion years.

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[StarTalk]

*Today's Lunch with a "Side Order of Science":*

[StarTalk]

New video: If we live in an expanding universe, how can galaxies collide with each other? Watch astrophysicist Neil deGrasse Tyson ease Eugene Mirman’s concerns about our Milky Way galaxy’s impending collision with the Andromeda Galaxy… in about 6-8 billion years: Neil deGrasse Tyson Explains Colliding Galaxies in an Expanding Universe

[pejunefa]

When he said 2020 @1:02 ... you should be more worried about the corona virus.

[teekamsuthar]

0:58 He should definitely be worried about 2020.. as now I can see it . 😂😂😂

[Encrylius]

I love how this has zero dislikes! Science people are the greatest!!

[vitruvyan]

Hi, StarTalk family. I'm a time traveller from year 2020 😁 I chose December 23, 2010 to witness your first uploaded video...now I'm returning to my own present time "linearly" AHAHA and as of now I'm in this timeline. Nice to see you.

[vegandew]

@1:00 definitely worry about 2020, trust me. Avoid if possible.

[karelfinn]

Nice Polyphonic Spree reference. It even made sense in context.

[ParaglidingManiac]

What's wrong with the sound!? Can't hear Neil without the other one screaming in my ears.

[danielabebe]

Not in terms of known units, because then, the unit of comparison would also be expanding, but in terms of units outside our realm. To us, it would appear as if they're their getting closer, but in actuality, they are maintaining the same space apart.

[MrTwhispers]

Kanderesraide NASA is working on a warp drive and want it done by 2100...

[cowboyyaj]

If the universe is expanding from the point of the Big Bang like a firewood explosion in the air, would the point of origin be hollow like a balloon where the fire spread outward leaving the middle empty? How come everywhere we look, the distance between galaxy are pretty much the same and there's no hollow spaces in the middle?

[GamesBond.]

And how exactly do you calculate the attraction between these 2 galaxies ? You cant just add up all these stars from a galaxy and pretend that they act like one gianormous star with the mass of 4 billion stars. Because their mass is scattered across thousands of light years and it is not concentrated in a point where you can measure it's mass as a whole. And if you cant measure it's mass as a whole, you can't measure it's gravitational attraction as a whole either. So you cant apply the formula of G for 2 entire galaxies.

That fomula only works for 2 individual objects or masses at a time. Not for billions of objects or masses at a time. Just because you add all the masses from one galaxy that doesnt make it a single mass. They are still a billion masses set apart by huge distances that you artificially combined into one. But a galaxy is not like that at all.

[Pathos]

lol... all of this speculation. Planet hopping? We haven't put a new telescope up in almost 20 years and haven't been back to the moon in how long? Yet we are to believe we'll be planet hopping?

[TheCodeGuy]

0:56 "...2020..." Did they know?

[danielabebe]

Could it possible for celestial bodies to maintain equal distances from each other as the universe is expanding? What I'm asking is that, could these bodies move at the perfect counter speed to the expanding rate of the universe so as to remain along each other for eternity? Is that possible, or is it to hard to maintain?

[holiday]

If thats the case, then neighboring stars like Proxima Centauri, Barnard will come nearer our Sun in millions or thousands of years from now?

[neanderthor]

Stars are far apart, so we may not hit another solar system... I get that. However, isn't there still the threat of being pulled into Andromeda's supermassive blackhole?