The event we would see if we live long enough, etc. is 100k years in earth’s future but 3.5 billion - 100k years in the past. So assuming 3.5 billion is exact, which isn’t true, it would be light emitted 3.4 billion years ago. So it’s upcoming from our perspective but happened so long ago words can’t describe.
Note that astronomers recently identified a galaxy, “EGS8p7”, which is about 13.2 billion-years-old. That’s only an estimated 600 million years (only!!) after the creation of this universe. This is interesting but hard to understand because I think it was written by someone who had no idea what the scientists were saying:
"The Big Bang is the theory that posits that the universe continuously expands so out of its original dense, hot state, which was characterized by high amounts of free-roaming electrons, protons and photons. After a cooling period, protons and electrons began to mix together to form hydrogen atoms that allowed light to travel through space. This allowed for galaxies, like our own, to begin to form, as gravity could then begin pulling matter together. In most known galaxies, the clouds of hydrogen atoms absorbed radiation emitted from newly-formed galaxies, a process known as reionization, but as the researchers show, for EGS8p7, this was not the case.
“If you look at galaxies in the early universe, there is a lot of neutral hydrogen that is not transparent to this emission,” [Adi] Zitrin said in a statement. “We expect that most of the radiation from this galaxy would be absorbed by the hydrogen in the intervening space. Yet still we see Lyman-alpha from this galaxy.” Lyman-alpha is an emission line of hydrogen through space, which, as stated above, usually indicates the formation of new galaxies or stars as the clouds of hydrogen absorb radiation. It is believed that Lyman-alpha emissions should have ended after the reionization process billions of years ago, but now the detection of Lyman-alpha lines may turn accepted astrophysical theories on their heads.
“The surprising aspect about the present discovery is that we detected this Lyman alpha line in an apparently faint galaxy…corresponding to a time when the universe should be full of absorbing hydrogen clouds,” [Richard] Ellis stated. One possible explanation for this previously unobserved phenomenon is that the absorption of radiation by the hydrogen clouds did not occur in a uniform manner across all galaxies. In addition, it is possible that EGS8p7 is populated by unusually hot stars and that the hydrogen clouds were created, or reionized, much earlier than was previously thought.
The novelty of the finding also has to do with the distance of the EGS8p7 galaxy from our own. Using spectrometer data the team gathered from NASA’s Hubble Space Telescope and the Spitzer Space Telescope, they were able to discover the galaxy’s redshift, or the red light that extends from the galaxy that indicated its distance, similar to the way some sounds cause the Doppler effect. In the case of EGS8p7, its redshift reading is 8.68, while prior to the discovery, the most distant galaxy we were aware of had a redshift of 7.73.
“We are currently calculating more thoroughly the exact chances of finding this galaxy and seeing this emission from it, and to understand whether we need to revise the timeline of the reionization, which is one of the major key questions to answer in our understanding of the evolution of the universe,” Zitrin says.
Me again if you made it this far. Astrophysics is not my strong point but two points leap out: huge redshift and hydrogen emission (which occurs when the atom’s electron drops in its orbital and this drop releases energy we can detect) where there should be none. BTW, I have no idea if this finding will stand up. I’m putting it here to show how far back in time we can see.
If you want weird stuff, look up the strange discussions about what happens when the sun explodes. If it explodes in a non-uniform matter, what would happen to the earth (presuming we’re not in the immediate blast)? That is, what happens to gravity when the sun suddenly loses all that gravitational pull and thus what imaginatively would happen to the planet if it “survives” and suddenly the relationship of earth to sun is blotto. Of course if the sun explodes uniformly then the question is what happens to the earth before the radiation eliminates us from existence (so quickly we would be unaware of it happening, like an infinite number of atomic bombs going off on top of you). This involves questions of how gravity is “transmitted” because if you think of the drawings of general relativity space - with the big deep well for a black hole, etc. - then if gravity at the sun changes then do we experience that without the speed of light lag? Since general relativity is local, the usual thought is we never find out because the change arrives with the radiation and if the sun explodes in a different direction then we’d feel the effects as the change in the gravitational field arrives in about 8 minutes 20 seconds. In Newtonian physics - this is the oddity - the effect is usually deemed instantaneous. But of course life follows Newtonian rules except when it doesn’t.