u/Psychological_Web151

This article states that our observable universe would have been 1.5m in the earliest stages of expansion that we can quantify.

First, I am going point out then ignore the fact that his intro refers to the entire Universe but only talks about the observable universe. That is irksome and causes confusion when not caught.

But, based on this, if Andromeda and the Milky Way are gravitationally bound and gravity is stronger than space expansion and we were once closer together, what caused them to separate to begin with? Was it because the force behind the initial rapid expansion was great enough to push us out and great enough to prevent gravity from keeping us together and it wasn’t until that force weakened that gravity could then pull us together?

If that is the case, and our expansion rate is a bell curve, what is causing the bottom of the bell? Is it that the force behind the expansion is growing or is it because the more space there is, the more space can expand (similar to population growth)?

Now that I properly understand the theory of the expansion of the universe, I have more questions…

An article from NASA on 6/16 (Why the Universe is Expanding Faster), the article states that dark energy is “an unsettling force that speeds up the separation of all galaxies.” And “this acceleration proves that dark energy overcomes the inward pull of gravity.”

Doesn’t this contradict why Andromeda is getting closer to us? Or is there no dark energy between us and Andromeda?

Yes I have seen that this has been asked many times and explained, but the explanations don’t make sense still so…

My first problem is that there are contradictions. Some explain that the universe is expanding, some say it’s infinite. Which is it? I will gladly except that the observable universe is expanding due to how we observe light, the timeline of the CMB, etc. and the universe itself is infinite. I’ll also except that the universe is infinite in the sense that it will expand forever and that the constant (or accelerated) growth is what defines it as infinite in the same way that one can count forever.

I read that space is expanding everywhere in every direction, which is why there is no center point. This makes sense for the observable universe but not the entire universe which was once much smaller. The Earth vs Earth’s crust or ballon theories assume that everything is on the edge of the universe, not somewhere between the center and edge or closer to the center. If the Earth expands to 3x its diameter, Australia becomes 3x further away, Canada does not (I’m in the US). I could use paralax to determine the center of the world based on that just as Hubble’s law should allow me to use paralax to find the center of the universe. In my mind, the only way we can’t find the center of the universe is if ythe observable universe is all on the same side of the universe and is only a small portion of the universe, which would mean the CMB doesn’t have much to do with the age or size of the universe, only the observable universe or that we are in the center of the universe.

EDIT: Thank you all for your responses. There were two things I didn’t understand and now do. First is that the universe is not expanding from one location but is expanding from every location. Many of the analogies did not explain this part. I have created a graphic (in a below reply) that should help understand that if there is a center, we will never find it. The second confusing part is that so many articles I’ve read leave out the “observable” part when discussing the size of the universe.

EDIT 2: The third thing I didn’t understand is that I always pictured the universe to be a growing ball, with everything being inside the ball. Using the balloon analogy, with the universe being the skin, changes things.

Yes I have seen that this has been asked many times and explained, but the explanations don’t make sense still so… ELI3…

My first problem is that there are contradictions. Some explain that the universe is expanding, some say it’s infinite. Which is it? I will gladly except that the observable universe is expanding due to how we observe light, the timeline of the CMB, etc. and the universe itself is infinite. I’ll also except that the universe is infinite in the sense that it will expand forever and that the constant (or accelerated) growth is what defines it as infinite in the same way that one can count forever.

I read that space is expanding everywhere in every direction, which is why there is no center point. This makes sense for the observable universe but not the entire universe which was once much smaller. The Earth vs Earth’s crust or ballon theories assume that everything is on the edge of the universe, not somewhere between the center and edge or closer to the center. EDIT: If the Earth expands to 3x its diameter, Australia becomes 3x further away, Canada is also 3x further away but it is not the same difference in distance. END EDIT. I could use paralax to determine the center of the world based on that just as Hubble’s law should allow me to use paralax to find the center of the universe. In my mind, the only way we can’t find the center of the universe is if ythe observable universe is all on the same side of the universe and is only a small portion of the universe, which would mean the CMB doesn’t have much to do with the age or size of the universe, only the observable universe or that we are in the center of the universe.

Edited to properly convey distances between countries.

EDIT: Thank you all for your responses. There were two things I didn’t understand and now do. First is that the universe is not expanding from one location but is expanding from every location. Many of the analogies did not explain this part. I have created a graphic (in a below reply) that should help understand that if there is a center, we will never find it. The second confusing part is that so many articles I’ve read leave out the “observable” part when discussing the size of the universe.

EDIT 2: The third thing I didn’t understand is that I always pictured the universe to be a growing ball, with everything being inside the ball. Using the balloon analogy, with the universe being the skin, changes things.