For Christian religions that believe the Rapture is a real thing, what, if anything, is said about the rest of the universe and the other entities that occupy it? Does the whole thing go away? Are the others leaving on another schedule?
What’s up (so to speak)?
Happy Birthday, oh purple-haired one.
Nothing, as far as I’ve ever seen.
The idea of the Rapture and the End Times predates modern astronomy, and the idea that the stars have planets of their own.
I also suspect that most such conservative/fundamentslist Christians believe that humanity is unique in the universe, as well as that the universe is only thousands of years old. The question of “but what about beings on other planets?” is meaningless or absurd to them.
Presumably the Devil will still want his slice of the pie.
Hey, Devil, when come back, bring pie! 
The most I can give you is the belief in a “new heaven(s) and a new Earth,” which would imply to me that everything else gets replaced, too. I don’t think they conceived of any life outside of earthly life, and then the Hellenistic Jewish mythological heavenly creature (like angels, demons, other gods). And, of course, the latter are no longer believed in by modern Christians.
Any ideas about aliens and whether they get their own savior or whatever would have come much later. The only ones I can think of offhand come from Mormons (which I don’t know enough to opine on) and C.S. Lewis and his insistence that myths could be true and that Aslan really was Jesus, not an allegory. So, in other words, other worlds seemed to get their own Jesus.
I don’t know if either believe in a Rapture, though.
The impression or implication I got, when I was still in the church, was that the universe basically vanishes and instead all that’s left is Heaven and a New Earth/Jerusalem.
If you’re asking whether it happens everywhere in the universe at the same time, what does “at the same time” mean, in the light of (Einsteinian) relativity?
There are two ways you can look at it.
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The Rapture is the beginning of the End Times. All those who are saved will be taken up to Heaven, and the world when then begin the time of the Tribulation, during which all evil will be destroyed. After that comes the restoration of the Church on Earth and the triumph of good for all time.
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The Rapture is the beginning of the End Times, and it is the first domino which ends with the destruction of the universe. The rest of eternity will be on another plane of existence.
Since those who are saved end up in Heaven either way, it’s a distinction without a difference.
In some form, I guess, but from what I understand the specific version of the idea that exists in modern evangelical Christianity is pretty recent – I think nineteenth-century, which would put it well into “modern astronomy” territory. I would be really surprised to hear, e.g. a Catholic or an Episcopalian talking about “the Rapture.”
I’m not here to debate-That is a whole 'nother forum. I just want clarification about what those religions mentioned in the OP believe about the subject…if anything.
I heard somewhere that Martin Luther thought that the pope was the antichrist. OTOH, as far as I can tell, el donald is the perfect candidate.
Pretty sure there are about as many answers to the OP as there are denominations believing in a Rapture. 
Pretty sure that’s why I didn’t ask this in Factual Questions.
Do either of those two ways deal with extraterrestrials?
Taking JD Vance as an example of those religions, as he can adopt them all and probably will when he thinks it benefits him personally and / or politically, he has stated the following:
The Pope should be careful with his interpretation of the doctrine. MAGA’s interpretation is better. Not bad for a Catholic who should respect the so called infallibility of the Pope in theological matters. The bishops are not amused, the Pope remains diplomatically silent. Cite.
Concerning other worlds and hypothetical aliens that may live there, they are not aliens, but demons. If the Rapture comes, they will be on the side of evil. They must be defeated. Their anihilation is a good thing. Cite. Only humans are worthy of redemption, and by no means all (see → skin colour).
By which I mean to argue that whatever those irrational believers do or say, whatever their “denomination”, is oportunistic, absurd, and wrong (factually, morally and ethically). Thinking about them and their beliefs is a recipe for being unhappy.
Or you could write a PhD on anthropological pathology.
Moderating:
This thread isn’t about the reformation, and was not intended to be yet another thread about Donald Trump. It’s not about what triggers the Rapture, either. It’s about what happens to the rest of the universe.
Thanks.
The idea is that those who are “righteous” in God’s eyes will be taken off the earth by God and enter paradise without dying an earthly death and will thus be spared the agony of the apocolypse. This is based on Genesis 5:24 which states that God did this with Enoch. According to biblical text, this will be very few in number compared to the general population.
Not a Christian but of course we don’t know that there is any life outside Earth. Certainly the enormous number of galaxies and star systems seems like it suggests life, even intelligent life, ought to exist in multiple other places. But right now, it’s possible that we are it.
Also not a Christian, but most Christian theology I’ve read is focused on the earth and on humans. A lot is it was conceived when “the stars are dots of light in the sky” was the common understanding. (a friend has an old dictionary that states that.)
Admittedly, modern rapture theology is (i think) more recent. But my guess is that the people who develop and promulgate these theories don’t care much or think much about anything other than “humans on the earth”.
For instance, i read the first in the Left Behind series, which takes place on the earth after the best people have all been raptured away, and it’s entirely set on earth. I guess, implicitly, its answer is “nothing changes off the earth”.