Quasars and galactive collisions
Galactic Collisions Collision of the Milky Way Galaxy with Andromeda (forming "Milkomeda")
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- In the last video on quasars I think I sparked some interest when I think I threw out the idea of the...
- Milky Way Galaxy actually colloding with the Andromeda Galaxy.
- Which people think will happen in three to five billion years.
- I threw out in the context of maybe, maybe the super massive black holes at the core.
- The galactic cores of each of those galaxys will start getting a little bit more material when that...
- collision happens.
- And maybe quasars will happen.
- I don't know.
- But given the interest in that what I wanted to do here is kind of an unconventional thing for the Khan...
- Academy.
- And actually show a video.
- And before I play the video I have to give credit where credit is due.
- This is a super computer simulation made at the National Center for super computing applications at NASA.
- And it's by B. Robinson of Cal Tech and L. Hernquist of Harvord University.
- And what I want you to remember is this is super sped up in time.
- Just to give an idea the amount of time it takes for a star about as far away as the sun to make one...
- orbit around the galactic core is two-hundred and fifty million years.
- And you're going to see that this is happening multiple times over the course of this video.
- So this video is actually spanning billions of years.
- But when you actually speed up time like that you'll see that it really gives you the sense of the actual
- dynamics of these interactions.
- The other thing that I want to talk about before I actually start the video is to make you realise that
- when we talk about galaxies colliding it doesn't mean that the stars are colliding.
- In fact there are going to be very few stars that actually collide.
- The probability of a star, star collision is very low.
- And that's cause we learned when we learned about interstellar scale that there's mostly free space...
- inbetween stars.
- The closest star to us 4.2 light-years away.
- And that's roughly thirty-million times the diameter of the sun.
- So you have a lot more free space than star space...
- or even solar system space.
- So lets start up this animation
- It's pretty amazing.
- And what you're going to see here, so these are just the...
- obviously, so one rotation is actually 250,000,000 years give or take.
- But now you see these stars right here...
- are starting to get attracted to this core.
- And then they're actually attracted to that core.
- And then some of the stuff in that core was attracted to those stars.
- And they get pulled away.
- That was the first pass of these two galaxies.
- Some stuff is just being thrown off into intergalactic space.
- And you might worry, maybe that'll happen to the Earth.
- And there's some probability that it would happen to the Earth.
- But it really wouldn't affect what happens within those stars solar systems.
- This is happening so slow.
- You wouldn't feel like some type of acceleration or something.
- And then this is the second pass.
- They've passed one pass and this is occurring over hundreds of millions or billions of years.
- And on the second pass they finally are able to merge.
- And all of these interactions are just due to the gravity over interstellar
- Or almost, you could call it, intergalactic distances.
- You can see they merge into what could be called a Milkomeda or maybe the Andromedy Way.
- I don't know, whatever you want to call it.
- But even though they've merged a lot of the stuff has still been thrown off into intergalactic space.
- But this is a pretty amazing animation to me.
- One; it's amazing to think about how this could happen over galactic space scales...
- and time scales.
- But it's also pretty neat how a super-computer can do all the computations...
- to figure out what every particle, which is really a star, or cluster of stars, or group of stars...
- is actually doing to actually give us a sense of the actual dynamics here.
- But this is, this is pretty neat, this is pretty neat.
- Look at that.
- I mean these are, you know, every little dot is whole groups of stars.
Be specific, and indicate a time in the video:
At 5:31, how is the moon large enough to block the sun? Isn't the sun way larger?
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