Uh oh lol
Uh oh lol
62 comments
-
-
Milky Way is going to collide with Andromeda… over the course of millions of years, and due to the distance between stars and other objects the two galaxies are just going to merge with each other and very few things will actually make physical contact.
-
Well, if they collide (and merge), they'll also fling a lot of stars into the void, but we aren't too sure anymore that's actually gonna happen. NASA explains why (YT, 2:30min).
-
Thank you very much for posting the video length. I wasn't gonna watch a 10 minute video but 2 was short enough.
-
Nobody liked those stars anyway…
-
Ah, you mean the void were nearly in the center of?
-
-
-
So blue is moving toward you?
I was always a bit confused with the explanations in high school. But I also got a D in physics so maybe I'm just dumb.
-
Blue shift, it's moving towards you, the photons are being "compressed" to a higher, bluer frequency. Redshift, the light is being "stretched" to a lower, redder frequency. Both only noticeable at significant fractions of the spped of light, relativistic speed.
Something ominous about the post is that a cosmic object that is moving towards you at a steady rate is consided "blueshifted" in the past tense, it's velocity is steady. If a galaxy is "Blueshifting" in the present tense, then that galzy is somehow accelerating at you, which is impossible unless it's under direct control by an entity, presumably a kardeshev level 3 civilization.
-
Yes which would be very odd for a far away object
-
No, it's just depressed and that makes us feel sad and worried for it.
-
I'm blue shifting-daba-dee-di
-
-
It's the doppler effect, but with light instead of sound, and for the same reason.
Thing emits sound/light waves at a constant rate: sound/light waves hit you at a constant rate.
Thing continues to emit the same sound/light at the same rate, but starts to move toward you: sound/light waves hit you at a faster rate, causing the sound/light to turn higher-pitched/bluer.
Thing continues to emit the same sound/light at the same rate, but starts to move away from you: sound/light waves hit you at a slower rate, causing the sound/light to turn lower-pitched/redder.
-
-
Oh no! We might not survive the collision to hundred fifty thousand years from now!
-
If it's billions of light years away it might be just a little longer than that.
-
*must be
-
might take a little bit o' while. you got plenty of time to start that pot roast in the slow cooker.
check on it around 100,000 and give it a stir.
-
-
-
If it's blue shifting from that distance, then it's likely some advanced technology is moving it in our direction.
There's not many other explanations for that.
-
Could it potentially be an object orbiting around the cosmic center that just so happens to have an orbital path that crosses us?
I have to admit that astronomy is what caused me to change majors, but that's because I stopped going to class when the lesson was, "This is a terrestrial planet, it's rocky," and my first exam was like, "If it's 5:45pm in Tanzina on October 15th, how many degrees is the moon above the horizon?"
-
Let's suppose that for some reason it's completely normal, and it's just simply speeding toward us.
OP says it's billions of light years away. Doesn't that mean that we still have a few billion years?
-
Since they didn't note extreme blue shift, probably several billions of years
-
-
-
Might be a dumb question, but if it's blue-shifting surely we wouldn't know it's far away in the first place? I thought the amount of redshift is broadly how we determine cosmic distances?
-
Armchair expert here
From my understanding blue and red shifting is mostly related to movement. Like when a firetruck run past you with sirens on, you can hear change in pitch when compared it moving towards you vs away from you.
It's a similar effect with galaxies, red shifting means that after the light was emitted the space between us has increased and the light kind of stretched out to longer wave.Now anyone with more knowledge on the subject, please correct me.
-
You're missing the point that the universe is expanding uniformly. That means two points acceleration away from each other is dependent on their distance apart. The further they are from each other the faster they accelerate from each other.
So GP is right. We measure red shift and infer distance.
-
Yes, but everything red shifts "naturally" as well as the light travels because of the expansion of the universe. So something traveling towards us will still red shift, just slightly less so. To determine distance you have to use something called the cosmic distance ladder. It consists of known properties of stellar objects that we can measure to determine the distance of objects.
-
-
Yeah, I'm pretty sure red shift is our best method for getting distances on billions of light year distant objects, no idea of it's the only one at that range
-
-
ELI5?
-
If something is red shifting, it's accelerating away from you. If something is blue shifting, it's accelerating towards you. An entire galaxy accelerating towards you is somewhat concerning.
-
Redshift comes from relative velocity (and other effects), not acceleration. Andromeda's light is blueshifted as it's moving towards us, but it's not accelerating.
-
On top of that, we've found that basically everything is redshifting as the universe expands. So to see a blueshifting galaxy would mean something potentially unnatural.
-
Right, but I don't get why this thread is full of people talking about collisions. Even if it was moving at the speed of light (it's not) it's still billions of years away.
It would just prove our theory of universe inflation to be incorrect.
-
-
You know how the sound of things moving from you changes? Towards you the pitch is higher, away from you it is lower. The same happens with light. We know how some things should look like, so if they are more toward red or blue, we know their speed relative to us. Blue = towards us = "we will collide" (you also do not collide with every car with a siren where you hear that effect).
-
Great explanation, thanks!
-
-
-
-
I'm blueshidding
-
Blue
wafbrownies?
-
-
You see an hughe comet in the sky......but which stand still and it gets bigger and bigger.
-
Humans in 200 years be like: ha ha warp drive go brr.
62 comments
Eh, the odds of actually colliding with anything is low enough. Plus the night sky would probably be even more breathtaking. I'm in
I think there's maybe more risk with the solar system being thrown off balance with other gravitational forces pulling things out of orbit. Even if earth just gets pulled away from the sun a little we are screwed. Or even the moon pulled away from earth somewhat.
I get what you're saying, but had to laugh at the use of "a little" here. The goldilocks zone in the solar system is roughly the between the orbits of Venus and Mars, and we're almost right in the middle of it, so "a little" is like 150 million km.
I would imagine that the first issue we would experience would be that the moon would be pulled out of Earth's orbit first and then we lose the ocean tides and the stable tilt of the earth. It would probably get worse from there.
Could the other galaxy please pull us just the correct distance away from the sun to cancel the effect of global warming?
Given the vastness of space, this is a lot less likely than you might think, and the process itself would likely take millenia anyway.
It's even safer. The odds that it's coming directly at us to "collide" is low. Moving towards us doesn't mean it's moving directly at us. If you're driving down the road, all cars going in the other direction get doppler shifted. They're coming towards you, they pass beside you (hopefully), and then they're moving away from you.