Collision of the Milky Way Galaxy with Andromeda (forming "Milkomeda"). Created by Sal Khan.
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- Are there any pictures of galaxies that are halfway through colliding? i mean with 200-300 billion galaxies there have got to be some.(54 votes)
- Yes. A good example is the Antennae Galaxies (NGC4038/NGC4039).
For a picture: http://en.wikipedia.org/wiki/File:Antennae_galaxies_xl.jpg(71 votes)
- If we do collide with Andromeda, and lets say our sun did hit another star what would happen? Also what if a farther away star say Beetlejuice collided with another star? 3rd question. Would we on Earth not really feel anything from such a huge collision? Not even an increase in some radiation or something?(8 votes)
- If our sun hit another star when the galaxy clashes with the Andromeda, then we're dead. You might think this is a stupid answer, but this is basically the simplest answer. If a star clashes with the sun, there would have been something like a mega nuclear explosion because of major nuclear fusion interruption. If that didn't kill us, the cold would have. And if a star like Betelgeuse (not Beetlejuice) hit another star, there would have been an incredibly large explosion, that even we would have been affected, the speed of the Earth would have been increased, which is major (at least by a day).(20 votes)
- But wouldn't the black holes burn out like other stars over that time?(5 votes)
- Black holes take time scales much longer than that to burn out. The video spans maybe 2,000,000,000 years. The average stellar black hole will take 10^66 years or 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 years to decay. A supermassive black hole (like the ones at the centers of the galaxies) will take 10^92 years to decay.(26 votes)
- Are there any other known galaxies that are predicted to collide in the future?(5 votes)
- Yes. Our own galaxy, the Milky Way, is actually predicted to collide with the Andromeda Galaxy in a few billion years.(0 votes)
- what I dont understand is why is the black hole dosent suck things up because i thought black holes always did that and dose anybody agree with me that the video was beautiful(7 votes)
- if you're inside the black holes event horizon, then you get sucked up. if you're outside the event horizon, then you're safe.(3 votes)
- The BIG question is: is our universe inside a black hole??(3 votes)
- I saw a video about that question but likely the answer is no. Truthfully, nobody knows what's inside a black hole.(3 votes)
- at2:45is the best but can the black holes collide though? and what would happen if even more galaxies collide with ours?(3 votes)
- When black holes "collide" they merge into a single black hole. In a galactic merger there are not many actual collisions of stars since there is a very large space between stars. After galaxies merge you are left with an elliptical galaxy.(3 votes)
- Will the overall mass of the galaxy formed after the collision of the Milky Way and Andromeda be more or less than the present mass of the Milky Way ?(3 votes)
- After the Milky Way and Andromeda become Milkomeda, I'm pretty sure they'll have more mass than the Milky Way before it collided with Andromeda.(3 votes)
- Is there anything bigger and brighter than a quasar?(3 votes)
- No, quasars are the most powerful event in our universe. While a supernova can outshine an entire galaxy for weeks, a quasar can 10,000 galaxies for millions of years!(2 votes)
- Does anyone know the mass of Andromeda's supermassive black hole? In order for quasars to happen, the supermassive black hole has to be in between 10^7 and 10^8 solar masses, so If it is less than 6 million solar masses, then Milkomeda (Andromeda Way) would not be bright enough a quasar.(2 votes)
- You are right that size doesn't matter, however mass does, the brightest quasars come from galactic nuclei that have in between 10^7 and 10^8 solar masses. I think that since the overall mass of the Andromeda Galaxy (including Dark Matter) is less than the Milky Way's, Andromeda's nuclei won't have enough mass to reach the Quasar sweet spot.(4 votes)
In the last video on quasars, I think I sparked some interest when I threw out the idea of the Milky Way galaxy actually colliding with the Andromeda galaxy, which people think will happen in 3 to 5 billion years. And I threw out in the context of maybe, maybe the super massive black holes at the core, the galactic cores of each of those galaxies 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 supercomputer simulation made at the National Center for Supercomputing Applications in NASA, and it's by B. Robertson of Caltech and L. Hernquist of Harvard University. And what I want you to remember, 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 250 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 a sense of the actual dynamics of these interactions. The other thing I want to talk about before I actually start the video is to make you realize 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 because we learned, when we learned about interstellar scale, that there's mostly free space in between stars. The closest star to us is 4.2 light years away. And that's roughly 30 million times the diameter of the sun. So you have a lot more free space than star space, or even solar system space. So let's start up this animation. It's pretty amazing. And what you're gonna see here, so these are just the-- obviously-- so one rotation is actually 250 million 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. So they passed one pass. And once again, we're doing this-- 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 through the gravity over interstellar-- almost you could call it intergalactic distances. You can see they merge into what could be called as 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 supercomputer can do all of the computations to figure out what every particle, which is really a star, cluster of stars, or group of stars is actually doing to actually give us a sense of the actual dynamics here. But this is pretty neat. This is pretty neat. Look at that. I mean, these are-- every little dot is whole groups of stars, thousands of stars, potentially.