r/whatif • u/Born_Mine_7361 • 3d ago
Science What if all matter outside the Solar System disappeared?
Imagine that, all of a sudden, every star, planet, and any other form of matter beyond the boundaries of our Solar System simply ceased to exist. Nothing would remain—no light, no residual radiation. What would happen from that moment on? What would be the immediate impact of this total absence?
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u/dodexahedron 3d ago edited 3d ago
We wouldn't know about it for a while.
We wouldn't even know it had happened to our closest stellar neighbor for 4.3 years.
All other effects also would not reach us for that long, because it all travels at C.
And since you can't see nothingness, it's not like we'd be able to see this expanding sphere of darkness in real time, except as it reached each additional object farther and farther away from where we are at a given time. We'd probably figure out something weird like that was happening due to the timing of things disappearing.
But, lacking any reason for it, we wouldn't be able to explain it or even confidently say that it was in fact what was happening (or that, in this case, had already happened).
The biggest effects would be sociological. Things like new religions forming and whatnot.
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u/Plenty_Unit9540 3d ago
Gravity moves at C
Nothing would change.
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u/dodexahedron 3d ago
Exactly the point.
Everything that matters moves at C.
Even for the center of the galaxy to "disappear" wouldn't be noticed for 26000 years, and the main effect would just be that our solar system would start moving in a straight line instead of its current orbit.
I suppose, if that were as sudden as the question lays out, once the effect reached this far, that might be the first thing to have a real and probably dramatic effect, due to inertia, but that's about it.
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u/MuckleRucker3 3d ago
The next generation would have no idea what Don Mclean was singing about in "Vincent"
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u/ShyBiGuy9 3d ago
That depends on what you consider to be the "boundary" of the solar system. The Heliosphere? The outer edges of the Oort Cloud?
The Heliosphere is about 100 AU distant on the leading side; light takes about 8.3 minutes to travel 1 AU, so we'd notice light failing to arrive from outside the Heliosphere about 13.8 hours later.
The Oort Cloud cloud, at the limits of the sun's gravitational influence, is hypothesized to possibly extend out halfway to Alpha Centauri. If that's the case, we wouldn't notice that's anything's wrong for more than two years.
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u/FollowingInside5766 2d ago
That's a pretty wild scenario! I think for starters, we wouldn't notice anything immediately. The light from beyond our solar system takes years to get here, so we'd still see the stars for a while, especially the closer ones, like in Alpha Centauri. But gradually everything would start going dark as the existing light fades, and our night sky would eventually have way fewer stars.
The big stuff would probably take a while to unfold too. No more gravitational pull from anything beyond the solar system would change things a lot. The Milky Way holds us kinda loosely in one of its spiral arms, so who knows? Maybe in the long, long term, the Sun's orbit through the galaxy might get funky. We might drift a bit, I guess, but it probably wouldn't matter much more to daily life here.
And, ok, the rest of the universe is basically where we get all our heavy elements from—like iron, gold, and stuff. If you think about it, everything heavier than hydrogen and helium came from older stars that blew up out there. Not sure how it'd affect future elements out there 'cause we basically already have what we’d need stored up on Earth. But, if we ever needed more heavy elements and couldn't mine or recycle enough, that could be tougher.
Space stuff and researchers looking at cosmic background radiation and other stellar phenomenon would be scratching their heads, though. Pretty much a whole field of study would go dark (pun intended). Science would hit all kinds of walls without the cosmos to study. It's like scientists would have to rethink a ton of theories ‘cause they'd lose all those clues about the universe's start and make-up.
It's kinda mind-blowing to think about how much we've relied on the rest of the universe for resources or just understanding our place. Makes you appreciate all that cosmic stuff, even when it feels like our little corner is all we need, huh?
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u/zrice03 2d ago
Since you include light and radiation, not just the objects emitting them, then we can assume all the light already in transit also vanishes. So instantly the night sky becomes completely black. And no more cosmic rays. But honestly I think that's pretty much it. All life on earth is based around the day/night cycle, or the lunar cycle in some instances. But both of those would still be intact. The solar system as a whole would drift on in a straight line, no longer bound to a galaxy, but space is so empty anyway that would also make little difference. Maybe the lack of cosmic rays reduces the amount of random mutations in lifeforms, but it's not the only (or even very large) source of mutation, so again not much change there.
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u/Larry5376 3d ago
I'm not sure. Probably something catastrophic eventually. Matter can't be destroyed
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u/Savings_Difficulty24 3d ago
I mean if it does, it's just converted into pure energy. Which that would be a major problem actually
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u/HookDragger 3d ago
Death as the remaining universe expands to die even more quickly to the big chill of maximum entropy
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u/mehardwidge 2d ago
Most people seemed to interpret this as a physics question.
It is also an interesting question about humans and culture: how would humanity react if, mystically, all light from outside the Solar System stopped arriving?
We would no doubt try to determine if other signals, like gravitational waves, still arrived, and then that leads to two questions. One where it is just dark, and another where every signal is gone.
Does society just go along basically the same, except it is a little darker at night? Do people decide we are in a simulation, or that aliens have put a barrier around our system? Do doomsday cults become common? Do existing religions incorporate the change into their theology?
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u/Turbulent-Name-8349 2d ago
Including dark matter?
Interestingly, we would still see the cosmic microwave background forever.
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u/SphericalCrawfish 2d ago
The long text makes this question much less interesting. I'm taking the everything as everything everything including gravitational effects.
Nothing happens physically. The sun starts flying in a straight line instead of turning close to 0 degrees every century. There would be a sudden tiny bit of force from the change in acceleration but it would be too small to notice.
Socially. Probably a lot of people jumping off buildings and doomsday cults. But give it 6 months and we would just be sad that there are no stars in the sky.
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u/Quietlovingman 3d ago
It would take thousands to millions of years after the event for us to notice considering how slowly light moves at cosmic scales. If instead a black void were to form immediately outside the edge of our solar system we would notice in about five hours, as the light inside the void would take that long to resolve.
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u/Superman246o1 3d ago
If instead a black void were to form immediately outside the edge of our solar system we would notice in about five hours, as the light inside the void would take that long to resolve.
That depends on how we define our Solar System. The Oort Cloud extends as far as 100,000 AU from the Sun, and if a black void were to form immediately beyond that, we wouldn't know about it for 18 months.
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u/Quietlovingman 3d ago
That's fair, I was defining it as just beyond the average orbit of Pluto.
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u/Superman246o1 3d ago
That's also fair. I, too, fondly remember the days when Pluto was perceived as the outermost object in the Solar System.
*Don't You (Forget About Me) plays*
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u/Snake_Eyes_163 3d ago
Sirius XM becomes just plain XM. Milky Way chocolate bar becomes just plain chocolate bar. Polaris vehicles stop working. The sky gets dark and the Annunaki perish, except for the ones who are here among us…