MOXPEARL25 t1_ja48rnj wrote
The Big Bang is often described as an explosion, but it's important to note that it's not an explosion that occurred in space; rather, it's an explosion of space itself. This means that the Big Bang did not occur at a particular point in space, but rather, it created space itself.
When we talk about an expanding ring of light from the Big Bang, we are referring to the cosmic microwave background radiation (CMB), which is the leftover radiation from the Big Bang. The CMB is often depicted as a "ring" because it is the furthest we can currently observe in the universe, and it is at the "edge" of the observable universe.
As for what is outside the CMB, the truth is that we don't know for sure. It's possible that the universe is infinite, and there is simply more universe beyond what we can observe. It's also possible that the universe is finite and bounded, in which case there may be some sort of boundary beyond the CMB. However, the nature of this boundary, if it exists, is currently unknown.
It's important to keep in mind that when we talk about the universe, we are talking about everything that exists, including space and time. So if there is something "outside" the universe, it is by definition not part of the universe. Therefore, the question of what is outside the universe may not be a meaningful question at all.
ExtremeQuality1682 OP t1_ja49e5e wrote
You are awesome, I'm not sure I understand entirely, or that anyone does but I understand slightly better. So the big bang did not follow the rules of physics and happened faster than the speed of light then? So there are theoretically dark galaxies that still have not had light reach them yet, and there always will be? Btw thank you in advance, you're awesome.
MOXPEARL25 t1_ja4ax3e wrote
While it is true that some parts of the universe are currently beyond our observable horizon, this does not necessarily mean that there are dark galaxies that we cannot see. Our ability to observe objects in the universe is limited by the speed of light, which is the fastest anything can travel. The farthest objects we can currently see are the ones whose light has had enough time to reach us since the beginning of the universe.
However, it is possible that there are areas of the universe where light has not yet reached us, and we cannot observe them yet. These regions are commonly referred to as the "unobservable universe." However, it is important to note that this is not the same as a "dark galaxy," which refers to a galaxy that emits very little or no visible light. Dark galaxies are still detectable through other means, such as their gravitational effects on surrounding matter.
Overall, our understanding of the universe is continually evolving, and there is still much we do not know.
So in a nutshell: We can only physically SEE so far. But by other means of measure we can detect certain energies further out into the universe. This one’s we can detect but can’t see are the “dark galaxies”. They still exist but are too far for us too see. And outside that is really unknowable.
RubyPorto t1_ja4d4ly wrote
>However, it is possible that there are areas of the universe where light has not yet reached us, and we cannot observe them yet.
Depending on the cosmological model you subscribe to, there are instead areas of the universe whose light will never reach us (assuming expansion continues), and we will never be able to observe. And areas where light from the past was able to reach us, but light emitted now will never be able to reach us.
For objects beyond a certain distance, the expansion rate of the universe is such that the distance between us and the object increases at a rate greater than the speed of light, meaning that photons emitted by that object will not reach us in finite time. (This does not mean anything is moving faster than the speed of light, to be clear.)
ExtremeQuality1682 OP t1_ja4e5a8 wrote
Oh, thank you. That makes it actually make more sense. I'm thinking as there was only 1 big bang. So our light wouldnt reach them, but that doesn't mean there's nothing. Like you said they're light wouldnt reach us either. So there isn't nothing just another universe expanding toward us. Theoretically of course. It was the concept of nothing that had my brain messed up.
RubyPorto t1_ja4gn19 wrote
I think my comment may not have been clear enough. There was only 1 big bang. There isn't another universe expanding towards us. This is all talking about one universe.
Imagine that the universe is represented by the skin of a balloon (just the 2d skin, not the internal volume). Cover the balloon with dots and pick one to call Earth. As you blow the balloon up, all of the dots will get farther from the earth dot, but the change in distance will be smaller for the near dots than the already far dots. Now imagine there's a speed limit for moving between the dots. If the rate at which the distance to the far dots is increasing is faster than that speed limit, you can never get from the far dots to the Earth dot.
apoeticturtle t1_ja6zmlv wrote
Unfortunately, imagining "nothing" beyond the balloon is where everyone gets lost. Most people, with sense, would easily counter-explain that the balloon could not expand without the "room" to be able to expand. I mean, sure the "thing" expanding also made/caused the actual phenomenon of expansion, but we'll let the philosophers continue haggling over that paradox.
RubyPorto t1_ja70srv wrote
Every model has limits. The point of the balloon model here is to explain how a cosmologic event horizon can occur.
I agree with you that it's limited as a way to visualize the general idea of the expansion of the universe, since it requires the same essential leap as not using a model (i.e. that the universe isn't expanding into/through anything).
apoeticturtle t1_ja7n728 wrote
Can you point me to any information on how the idea of this "expanding into nothing" can be conceptualized?
sofar55 t1_ja9fn4t wrote
Going back to the balloon analogy, the dots are moving away from each other. Without the vertical dimension, the "universe" of the balloon surface is getting bigger, but what is it expanding into? The space between dots is expanding, but where is the space coming from?
In this model, the dots dont understand elastic stretching. In the universe, it's believed that empty space is just expanding and pushing everything apart, but we don't know how.
RubyPorto t1_ja9asum wrote
I'm not sure I can. Every physical analogy is going to be expanding into a medium.
It's also not really "expanding into nothing." The coordinate plane of space is itself expanding, full stop. It's not expanding into anything (or nothing).
It's a fact that you just have to decide you're ok with, without a relatable model to compare it with.
apoeticturtle t1_jabgplj wrote
There are many things in my life that I do have to decide if I am OK with, but thankfully not this one. I cannot even imagine "nothing" and having less than nothing (that which lies beyond our Universe's edge) is as mind-boggling as it is speculative. All the energy in our Universe may be just a tiny fraction of all the energy everywhere/when. It seems more likely, to me, that our Universe is a tiny part of something bigger. If not, what a waste of energy and time/space.
UniversalAdaptor t1_ja4gpx5 wrote
The speed of light only applies to matter and energy. Space is free to expand at any speed, it does not have any limit (that we know of). Yes there are galaxies beyond the cosmic horizon that are still coming into view. Although since galaxies are hundreds of thousands of light years across, it therefore would take that much time for one to come into view. We don't know how big the universe is but we do know it is at least several times bigger than the observable universe.
sofar55 t1_ja9g013 wrote
Wait, how do we know it's "several times" bigger than the observable? I haven't seen anything to reference the actual size of the entire universe beyond observable.
turnedonbyadime t1_ja4jqax wrote
You don't understand because this entire concept is wildly far beyond anything humans were ever meant to understand. Maybe the only satisfying answer to this kind of question is coming to peace with the fact that we'll likely never have a satisfying answer.
ExtremeQuality1682 OP t1_ja57cbl wrote
Ha, explain to my brain like it's 5 how to do that one while you're at it. I'm just ribbing you. My brains the one that's a jerk.
phunkydroid t1_ja5f0ro wrote
>So the big bang did not follow the rules of physics and happened faster than the speed of light then?
The expansion of space is not limited by the speed of light. That speed applies to things in space, not to space itself.
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