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Feb
6
comment How does light affect the universe?
Since most of what we are looking at, at great distances, are very "young objects" existing in a much smaller/denser universe I would expect us to see a somewhat uniform universe. But that does not mean that if we had been elsewhere, and experienced 13.7 billion years, that what we would see there is the same as what we see here, now. Regarding the space ship journey; your story is true if the region of space your travel to is as dense as our region of space. If not, that region might be older or younger than our region of space.
Feb
6
comment How does light affect the universe?
@pela That gradient in time is what implies that the universe is brighter for objects far away. As light and gravity have propagated for 10 billion years before reaching us, the source of that light was in a much brighter universe. Since simultaneousness is relative, that object is currently in a bright universe, while we are in a dark universe (and vice versa); thus brightness must be a gradient.
Feb
5
comment How does light affect the universe?
@pela Another observer in another place (5 billion light years away) in the universe will probably observe a similar density as we do, in 5 billion years. But at that time we will see a darker universe. It must be a gradient, it can't be homogenous. Also, due to the vastness of the universe, if we look south at a distant star 13 billion ly away, and then look north 13 billion ly away, those two stars are very close to each other. Looking a bit further, the stars actually occupy the same space - and that obviously will appear homogenous.
Feb
5
comment How does light affect the universe?
@pela Thank you for calculating that. I was initially going for a much lower number (10^40), but got a bit brave. Still I am surprised. Curious as to how you calculate that. Regarding homogeneousness, due to relativity - the universe is brighter the further you look, for the object you look at due to that object being in a younger universe. The object you are looking at will appear to have stronger gravitational forces affecting it. The density of empty space due to radiation is a function of distance from the observer.
Feb
5
comment How does light affect the universe?
@kubanczyk I agree, and I was not seeking for you too claim that science proves anything. I simply don't understand how scientist can feel that it's logical to conclude that due to us seeing isotropic background radiation- everybody else must be seeing isotropic background radiation,regardless of where they are. In fact, we know that an object 10 billion light years away from us is, right now as we are looking at it, existing in a brighter/younger universe and it's difficult to know if that is isotropic.Every object must see themself as being in the darkest area of the universe, us included.
Feb
5
comment How does light affect the universe?
@pela It does not imply homogenity. I don't understand why it even suggests homogenity. If you draw 10^100 infinitely long and fairly thin lines throughout the universe, the odds of any one of those lines intersecting with earth is still tiny. You can't conclude that since nobody is pointing a flashlight at you, there are no flashlights. And you can't see the ray coming from a flashlight, unless it's pointing at you.
Feb
4
comment How does light affect the universe?
@kubanczyk “Make things as simple as possible, but not simpler.”. Regardless of that; you can't possibly conclude beyond doubt that photons are evenly distributed throughout space, based solely on the fact that we are receiving them somewhat evenly distributed at this tiny planet. There are many photons that we will never receive here, and you don't know where they are heading or how many they are. There might/probably are trillions of super energetic GRBs shooting through space that we will never see; simply seeing them would cause a sterile earth.
Feb
4
comment How does light affect the universe?
Yes, so it appears isotropic in our region of space. But I don't consider this proof that photons are isotropic in their distribution throughout space. That very distant star you're looking at is, from our perspective, in a universe that is only 47000 years old.
Feb
4
comment How does light affect the universe?
The biggest a-ha in your answer was that photons are redshifted - which I haven't considered. Just curious: regarding isotropic distribution of photons, how can you be sure about that?
Feb
4
accepted How does light affect the universe?
Jan
6
awarded  Yearling
Jun
8
comment What would happen if a wormhole gets swallowed by a black hole?
I don't think you can differentiate between the two ends of a wormhole. Both ends would be the same - i.e. it's non-orientable. If there is a black hole next to a wormhole, would not the gravitational effects of the other black hole also work through the wormhole itself?
Jun
8
comment What would happen if a wormhole gets swallowed by a black hole?
@HDE226868 Didn't Einstein predict wormholes? If you're being nitpicking - we don't even know that black holes exist. For all you know, we're all being emulated inside a computer.
Jun
8
comment What if the black hole in the center of the galaxy grew faster?
Some people have speculated that black holes are worm-holes. Could not a black hole grow from both "ends"?
Jun
8
comment What if the black hole in the center of the galaxy grew faster?
@RobJeffries This is also not a forum for being arrogant. The question is not imaginary and the visual effects that this would cause is what's interresting.
Jun
5
comment What if the black hole in the center of the galaxy grew faster?
@RobJeffries It may be difficult to imagine this with a black hole. I suggest another object; the "Strangeularity" in the center of the milky way. It increases in mass continously, due to the "Weirdness Effect". Being in vincinity of something like this; would we see a gradual change in the redshift of for example M31?
Jan
6
awarded  Yearling
Sep
1
comment World line coordinate finiteness
Finally; I fully adopt the notion that time and space is exactly the same. This implies that also physical distance is four dimensional, allowing us to observe particles as not being at the same "spot" i.e. have a physical shape - while another observer may see it as a singularity.
Sep
1
comment What is the probability that there is life on other planets?
Drakes equation should take relativity into account... It'll significantly reduce the chances for life existing elsewhere; as seen by us.
Sep
1
comment World line coordinate finiteness
@HDE226868 It seems obvious that at crossing the event horizon an object is "spaghettified" recursively until you're left with the tiniest of particles, or perhaps some energy/particle hybrid. Eventually that particle will reach the center of the singularity, and the spaghetification will be working internally on the particle more than externally. This will look like universal shrinking, which I believe is indistinguishable from an accelerating universal expansion - leading to a big freeze. In any direction, you're looking at the center of the black hole we originally entered - leading to CBR.