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Current time:0:00Total duration:3:34

Video transcript

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 three to five billion years and I throw out in the context of maybe maybe the supermassive black holes at the core of 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 this is a super computer simulation made at the National Center for supercomputing applications in NASA and it's by B Robertson of Caltech and L Hearn Quist of Harvard University and what I want you to remember is this 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 250 million years and you're going to see that this is 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 I want to talk about before I actually start the video is to make you realize when we talk about galaxies colliding it doesn't mean that the stars are colliding in fact they're 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 look to earned 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 forever 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 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 starting to get attracted to this core and then they're actually attracted to that core and then they're 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 two years but it really wouldn't affect what happens within those stars solar systems this is what 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 a occurring over hundreds of millions or billions of years and then on the second pass they finally are able to merge and all of these interactions are just through the gravity over interstellar or almost you could call it intergalactic distances you can see they merge into what could be called as a milk Amida or maybe then dramedy way I don't know what whatever you want to call it but even though they've merged a lot of the stuff it's Patil been thrown off into intergalactic space base but this is a pretty amazing animation to me i won it's amazing to think about how this could happen over a 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 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 thousands of stars potentially