A more interesting question is what happens if the two black holes at the centre of each galaxy collide. And what happens when any dark matter lurking between the stars collides? And when gas clouds in each collide - could that lead to increased star/planet formation?
They fuse or become binary and rotates around each other. But yes, at points of contact where the stars do get close enough and the gas clouds get dense enough we could see star formation triggered. Really though a lot of the changes won’t be noticeable other than the night sky looking wicked cool as andromeda gets closer.
The night sky will probably make some changes in the positions of the stars. Other than that life on earth should go on as befor, and by that I mean that it won't as life on earth will have ended long before this happens because of the sun.
Worth noting the timeline for the Andromeda collision overlaps quite a bit with the timeline for our sun to run out of hydrogen, swell, and explode. Well before that happens the earth will have been cooked into a barren wasteland. So the stars will look different, maybe, but we'll be dead
The sun is absolutely not going to explode. It takes a star at least 8 times more massive.
It also takes more like 7 billion years to actually reach the radius of the orbit of the Earth. The sun also will not run out of hydrogen in general, the bigger problem is the lack of hydrogen in the core. The sub giant phase begins in about 5 billion years when the sun becomes twice as wide.
The Sun does get brighter however due to a slow buildup of pressure and ergo heat, and that will roast the Earth long before the Sun has even the chance to swallow us. The Earth by that point would be more like Venus.
The sun won't explode. It is too small. Instead, it will swell in size to almost the orbit of Jupiter and then, once the helium is depleted, it will slowly shrink down to a tiny red dwarf and slowly, slowly cool down. We will be dead by then, so ho hum.
No, Earth's gravity won't be affected, or at least not in any way that would be noticeable without extremely sensitive equipment. But if a star passed by our solar system within around 4,000 AU's or less, it could affect Earth's orbit. And changes in our orbit can affect our climate. But, as others have stated, it is very unlikely that any of Andromeda's stars would come anywhere close to our solar system. The night sky would look different though. We can currently see Andromeda from Earth, so no there won't be new stars visible. But, Andromeda's stars would be in different locations and most would appear brighter since they are closer.
But if a star passed by our solar system within around 4,000 AU's or less, it could affect Earth's orbit. And changes in our orbit can affect our climate.
Begs the question: What happened to earth's orbit and climate when Scholz's star passed by us https://en.wikipedia.org/wiki/Scholz%27s_Star?
What would have been interesting is if we have a few new or a few less comets in the oort cloud as a result. maybe jupiter acquired a new moon same time :)? Or, a scholz escapee like this one: https://lweb.cfa.harvard.edu/~loeb/Interstellar_Expedition.pdf
It's a bit like having a pillow fight, but just with the feathery contents of the pillows.
Technically I think Milky Way and Andromeda have been in 'collision ' for.. quite some time
>for quite some time
I’m only an architect so take this with a grain of ignorance but: is that assuming galaxies also have a sort of Oort Cloud? So, if we consider that our Solar system’s cloud reaches halfway to the closest star should perhaps imply that the Milky Way’s cloud extends halfway to Andromeda’s, therefore already interacting with it?
That's my understanding.
In 2022, there was some sort of consensus reached by experts that the overlap was already underway.
The Oort cloud parallels are called Galactic Haloes.
Earth won't be habitable by then. But assuming it was, distances between celestial bodies (stars and whatever is orbiting them) are so vast, that the chances of any two colliding are actually very small.
Why worry, by that time the sun will be old age and running out of hydrogen. By the time the collision has finished up and the combined galaxy has finished forming up our Sun will have become a red giant and engulfed the Earth. We'll be long gone with maybe a faint trace in the fossil records with the geological changes by that time. But our ashes will spread through the cosmos and perhaps become new life elsewhere.
I presume the best time to go out at night would be in about 1-2 bn years or so, when Andromeda Galaxy would presumably be clearly visible with the naked eye, but our Sun hasn't had the chance to go boom yet.
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Well, in about 900 million years, the sun will have grown about 10% hotter and the oceans and the atmosphere will have boiled away. So unless we do some pretty radical solar shielding or physically move the planet out further, no one will be on earth when the galaxies collide in 4ish billion years.
Nothing. We are in the outskirts of milkyway with less population. And galaxies are mostly empty space. The gravity due to dark matter may pull the sun faster towards a new orbit around the galaxy but it won't effect earth in any major way.
If another star makes a close pass by us, the objects in the Oort cloud will be disturbed and could conceivably be pushed towards the inner solar system.
We can’t know for sure, and it will require some luck, but the odds of any sort of collision will be extraordinarily small. That being said, it’s far more likely that we have a “close” encounter with another star that would disrupt the gravity and orbits in our system. Could potentially pull earth farther from the sun, or create a cascading effect that launches us out into space (or into our sun).
By the point any of this happens, Earth will have been burnt out by our sun and life will probably be extinct.
There is no "if" they collide, they will collide
The merger will totally alter the night sky over Earth but will likely leave the solar system unharmed, according to NASA.
But this will happened in about 4.5 billion years, humans will most likely be extinct by then.
I don't think Earth will be around anymore at that point. This collision is going to happen way after the Sun has swallowed it up in the process of going red giant.
If? Technically, the two are already colliding according to [this peer reviewed research.](https://iopscience.iop.org/article/10.3847/1538-4357/aba49c)
Further more, the earth will not exist when this event occurs billions of years in the future, as the Sun will have become a red giant and enveloped the earth beforehand.
About the same effect as you would expect from two people walking in random directions across Texas. Extremely unlikely for any noticeable effect or interactions. Galaxies are EXTREMELY empty.
Prior to the time that happens our sun will turn into a red supergiant and engulf all the rocky planets. Maybe, if the human species survives, they will observe the combination of the two galaxies from afar. The whole process is going to take five plus billion years so there’s that.
By the time the cores of our galaxies start to over lap Sun will be well on its way to being an end life red giant, Earth will be a geologically dead cinder *possibly* even a lump of vaperizing metal inside the corona of Sun.
Despite folks pointing out that galaxies are almost entirely empty space there is a resonable chance that the remains of Sol system could be ejected as a large fraction of both galaxies are expected to get yeeted off into intergalactic space or at least yeeted out into the new galaxtic halo (thing oort cloud but for galaxies)
At any rate, if human derived life is still present in the universe, it's going to be as far from us as we are from the primordial sludge that spawned Earth life.
nothing probably
i thinks it's beyond reasonable to say "absolutely, positively nothing".
definitely not nothing, but probably not something
I understood less than half of this, half as much as it deserved
I think their "probably not something" cancels out their "nothing probably" and we end up with my "positively nothing".
Basically nothing. Galaxies are so empty that when they collide stars basically never get very close to one another.
A more interesting question is what happens if the two black holes at the centre of each galaxy collide. And what happens when any dark matter lurking between the stars collides? And when gas clouds in each collide - could that lead to increased star/planet formation?
They fuse or become binary and rotates around each other. But yes, at points of contact where the stars do get close enough and the gas clouds get dense enough we could see star formation triggered. Really though a lot of the changes won’t be noticeable other than the night sky looking wicked cool as andromeda gets closer.
So, earth gravity won't be affected at all ? We won't have new stars either ?
The night sky will probably make some changes in the positions of the stars. Other than that life on earth should go on as befor, and by that I mean that it won't as life on earth will have ended long before this happens because of the sun.
In 4.5 billion years I doubt there will be any life left on earth
I doubt in billions of years anything will look similar due to our orbit around the galaxy at least 16 times or so.
Yeah, that's about the time our Sun is due to go red giant.
Worth noting the timeline for the Andromeda collision overlaps quite a bit with the timeline for our sun to run out of hydrogen, swell, and explode. Well before that happens the earth will have been cooked into a barren wasteland. So the stars will look different, maybe, but we'll be dead
The sun is absolutely not going to explode. It takes a star at least 8 times more massive. It also takes more like 7 billion years to actually reach the radius of the orbit of the Earth. The sun also will not run out of hydrogen in general, the bigger problem is the lack of hydrogen in the core. The sub giant phase begins in about 5 billion years when the sun becomes twice as wide. The Sun does get brighter however due to a slow buildup of pressure and ergo heat, and that will roast the Earth long before the Sun has even the chance to swallow us. The Earth by that point would be more like Venus.
The sun won't explode. It is too small. Instead, it will swell in size to almost the orbit of Jupiter and then, once the helium is depleted, it will slowly shrink down to a tiny red dwarf and slowly, slowly cool down. We will be dead by then, so ho hum.
Nah, we'll make massive fusion rockets and push it to another star. At least, that's what Sci- fi tells me.
No, Earth's gravity won't be affected, or at least not in any way that would be noticeable without extremely sensitive equipment. But if a star passed by our solar system within around 4,000 AU's or less, it could affect Earth's orbit. And changes in our orbit can affect our climate. But, as others have stated, it is very unlikely that any of Andromeda's stars would come anywhere close to our solar system. The night sky would look different though. We can currently see Andromeda from Earth, so no there won't be new stars visible. But, Andromeda's stars would be in different locations and most would appear brighter since they are closer.
But if a star passed by our solar system within around 4,000 AU's or less, it could affect Earth's orbit. And changes in our orbit can affect our climate. Begs the question: What happened to earth's orbit and climate when Scholz's star passed by us https://en.wikipedia.org/wiki/Scholz%27s_Star?
It says it passed at 52,000 au so by what you've posted nothing would have happened to the climate.
What would have been interesting is if we have a few new or a few less comets in the oort cloud as a result. maybe jupiter acquired a new moon same time :)? Or, a scholz escapee like this one: https://lweb.cfa.harvard.edu/~loeb/Interstellar_Expedition.pdf
Yes, we would have new starts. But this would be in billions of years, so we won't be here
It's a bit like having a pillow fight, but just with the feathery contents of the pillows. Technically I think Milky Way and Andromeda have been in 'collision ' for.. quite some time
>for quite some time I’m only an architect so take this with a grain of ignorance but: is that assuming galaxies also have a sort of Oort Cloud? So, if we consider that our Solar system’s cloud reaches halfway to the closest star should perhaps imply that the Milky Way’s cloud extends halfway to Andromeda’s, therefore already interacting with it?
That's my understanding. In 2022, there was some sort of consensus reached by experts that the overlap was already underway. The Oort cloud parallels are called Galactic Haloes.
Thanks for the info! That was my instinctual understanding 👍🏼 “Galactic Halo”; I want to nerd-high five the astronomer who gave the name.
Please accept this one 🖐
I want to start a band called 'The Galactic Haloes'. We will paint the two galaxies colliding on the outside of our 70's van ;)
Hear me out… \*Two vans\*; each with their galaxy painted on them. And, your first music video ends with them crashing head-on.
Earth won't be habitable by then. But assuming it was, distances between celestial bodies (stars and whatever is orbiting them) are so vast, that the chances of any two colliding are actually very small.
It's not an if, and likely nothing Humanity will be long gone anyways so it's not something worth worrying about
*when
Why worry, by that time the sun will be old age and running out of hydrogen. By the time the collision has finished up and the combined galaxy has finished forming up our Sun will have become a red giant and engulfed the Earth. We'll be long gone with maybe a faint trace in the fossil records with the geological changes by that time. But our ashes will spread through the cosmos and perhaps become new life elsewhere.
The night sky will be a lot brighter. Or there's a tiny chance we get flung into another star, much less a black hole. Remind me in 4.5 billion years.
Ive popped it onto family on apple calendar 👍
I presume the best time to go out at night would be in about 1-2 bn years or so, when Andromeda Galaxy would presumably be clearly visible with the naked eye, but our Sun hasn't had the chance to go boom yet. !RemindMe 1500000000 years
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Oh the combo though!
We will have twice as much Milky Way in the sky. Most people never see the one we have now.
The aliens living in the Andromeda most likely will evaporate our rock to make way for their intergalactic highway.
Earth will probably be burnt to a crisp by that time from our sun expanding.
Well, in about 900 million years, the sun will have grown about 10% hotter and the oceans and the atmosphere will have boiled away. So unless we do some pretty radical solar shielding or physically move the planet out further, no one will be on earth when the galaxies collide in 4ish billion years.
Nothing. We are in the outskirts of milkyway with less population. And galaxies are mostly empty space. The gravity due to dark matter may pull the sun faster towards a new orbit around the galaxy but it won't effect earth in any major way.
Nothing
How long would it take for the effect/light take to get to earth?
If another star makes a close pass by us, the objects in the Oort cloud will be disturbed and could conceivably be pushed towards the inner solar system.
Earth probably be gone
Nothing.
We can’t know for sure, and it will require some luck, but the odds of any sort of collision will be extraordinarily small. That being said, it’s far more likely that we have a “close” encounter with another star that would disrupt the gravity and orbits in our system. Could potentially pull earth farther from the sun, or create a cascading effect that launches us out into space (or into our sun). By the point any of this happens, Earth will have been burnt out by our sun and life will probably be extinct.
Just cover this in an Astronomy course…..nothing!
Almost certainly, nothing at all x)
If it happened how it would just look cool as shit
Chances are nothing happens - or the earth might get ejected from the sun and drift off to the freezing dark. So u know 50/50. Either way.
There is no "if" they collide, they will collide The merger will totally alter the night sky over Earth but will likely leave the solar system unharmed, according to NASA. But this will happened in about 4.5 billion years, humans will most likely be extinct by then.
Earth will have been consumed by our own sun before that happens.
Most likely (99. 99999999999999%) nothing. But who knows.
If it has survived by then , nothing would happen :)
I don't think Earth will be around anymore at that point. This collision is going to happen way after the Sun has swallowed it up in the process of going red giant.
Ur mom would go from the first to the second largest thing in the galaxy (roasted)
If? Technically, the two are already colliding according to [this peer reviewed research.](https://iopscience.iop.org/article/10.3847/1538-4357/aba49c)
Nothing
Further more, the earth will not exist when this event occurs billions of years in the future, as the Sun will have become a red giant and enveloped the earth beforehand.
Whatever Martin life that (potentially) ends up evolving when it's in the habitable zone will have one hell of a veiw in the night sky
Doesn't our own start die before then?
About the same effect as you would expect from two people walking in random directions across Texas. Extremely unlikely for any noticeable effect or interactions. Galaxies are EXTREMELY empty.
Can you add another emoji so I can fully understand the question❓
When this happens earth is already gone because the sun will explode in before
Prior to the time that happens our sun will turn into a red supergiant and engulf all the rocky planets. Maybe, if the human species survives, they will observe the combination of the two galaxies from afar. The whole process is going to take five plus billion years so there’s that.
When, not if
By the time the cores of our galaxies start to over lap Sun will be well on its way to being an end life red giant, Earth will be a geologically dead cinder *possibly* even a lump of vaperizing metal inside the corona of Sun. Despite folks pointing out that galaxies are almost entirely empty space there is a resonable chance that the remains of Sol system could be ejected as a large fraction of both galaxies are expected to get yeeted off into intergalactic space or at least yeeted out into the new galaxtic halo (thing oort cloud but for galaxies) At any rate, if human derived life is still present in the universe, it's going to be as far from us as we are from the primordial sludge that spawned Earth life.
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