Why does the Universe have so many galaxies?

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Size of the universe

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I know this question doesn’t really make sense but the absurd enormity of the universe always made my head hurt. A single galaxy alone has more then enough stars to satisfy the curiousity of any sentient being. Why 2 trillion? It’s just insane. Why did nature have to create so many? The spaces between these things are so vast; and the very laws of physics makes it impossible for anything that lives in it to travel between them. I don’t know if their is a God but I do like the idea that the universe is a living thing. It’s literally everything their is. Maybe it created itself. Who knows? I just don’t know why it has to be so big.
 

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  • #2
anorlunda
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Like all motion is relative, big is in the eye of the beholder.

We can't tell how big the universe really is, but many believe that it is actually infinite.

Do not confuse big with infinite. Nothing of finite size can ever grow to infinity, nor can anything infinite ever shrink to finite size.
 
  • #3
Vanadium 50
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One might as well ask why are there over 250,000 species of beetles.
 
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One might as well ask why are there over 250,000 species of beetles.
It’s not the same. 250,000 is big number but it’s not an imaginary number. Someone could catalogue all those beetles in a life time. 2 trillion galaxies composed of a 100 billion to a trillion stars gives us 600 sextillion stars objects 10000x bigger than our planet. Our brains aren’t sophisticated enough to rationalize that number. 250,000 is big enough to hurt.

I just can’t believe the Big Bang had that much energy to create all that stuff. It doesn’t makes sense.
 
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  • #5
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The universe is not obliged to "make sense" to human beings. Btw. your question seems to be more related to philosophy than to physics.
 
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  • #6
PeroK
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It’s not the same. 250,000 is big number but it’s not an imaginary number. Someone could catalogue all those beetles in a life time. 2 trillion galaxies composed of a 100 billion to a trillion stars gives us 600 sextillion stars objects 10000x bigger than our planet. Our brains aren’t sophisticated enough to rationalize that number. 250,000 is big enough to hurt.

I just can’t believe the Big Bang had that much energy to create all that stuff. It doesn’t makes sense.
Things only make sense or don't make sense if you have some known basis for your logic. There is no basis on which to estimate the size of the universe. All we can do is observe what there is.

If you hypothesize a theory for the origin of the universe and that hypothesis precludes the observed number of galaxies, then that theory cannot be right. If the universe makes no sense based on some a priori assumptions, then from the evidence those assumptions must be wrong.
 
  • #7
Buckethead
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Summary:: Size of the universe

I know this question doesn’t really make sense but the absurd enormity of the universe always made my head hurt. A single galaxy alone has more then enough stars to satisfy the curiousity of any sentient being.
Satisfying the curiosity of us sentient beings is not likely the intent of the universe. So it follows that there may be another reason if there is a reason at all.

Why 2 trillion? It’s just insane. Why did nature have to create so many? The spaces between these things are so vast; and the very laws of physics makes it impossible for anything that lives in it to travel between them. I don’t know if their is a God but I do like the idea that the universe is a living thing. It’s literally everything their is. Maybe it created itself. Who knows? I just don’t know why it has to be so big.
If one assumes (as I often do) that there is a reason for everything and that everything is interconnected as one giant network, then one would also have to assume that the size of the universe is what it is for a reason. Given that parameter, one idea that comes to mind for me is that if the universe were smaller, structures such as galaxies might not be able to hold up. The orbits of stars about our our galaxy might be different than what we are familiar with due to Mach's Principle, or perhaps GR would be affected. I am not qualified to say. But my intent here is to show a large universe may be necessary for anything to exist.

This may or may not be a philosophical question, but I think down the road it may become clear why it is so large. We may only need more data.
 
  • #8
phinds
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I just can’t believe the Big Bang had that much energy to create all that stuff. It doesn’t makes sense.
Oh, it's MUCH worse than you seem to realize. The "Observable Universe" is what you have referenced. The actual entire universe may be, as Anorlunda pointed out, infinite. In any case, if it's not infinite we are pretty confident that it is at least MANY orders of magnitude larger than the observable universe, so the numbers you are concerned about are at most a rounding error in the overall scheme of things.
 
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  • #9
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When asking a question like "Why does the Universe have so many galaxies?" I think it might be worth asking your self why do you think there is a "why" there to answer at all? Asking "why" implies some sort of intent, something did something, why did it do it? Its implying causality or reason. Asking how might be better. I don't think there are answers to the "why", and I don't there there will be for a lot of our questions. Best not to ask why. lol.
 
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  • #10
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To quote Aristotle, "The natural way of [studying physics] is to start from the things which are more knowable and clear to us and proceed towards those which are more knowable by nature; for the same things are not knowable relatively to us and knowable without qualification."

So we start from the basis of our senses and construct simple models based on those, but there is no reason to assume that is all there is or that the universe is simple for us to understand. The universe does not exist for us - for the vast majority of its existence and in the vast majority of its expanse, humans simply did not exist and that made no difference to the universe as a whole. All that is necessary is that we are capable of comprehending the part of the universe in which we live to such an extent as helps us survive (or else we would not have evolved). Anything beyond that is incidental.

As to why there are so many galaxies, a better question would be "why should there not be?". If the universe is such as to allow one of a type of thing to come into being, it would be reasonable to expect there to be more of that type. Wherever in the universe the causes that led to the formation of our galaxy are present, a galaxy like our own could be expected to form, and the only limitation on this would be if there was insufficient matter to create more than one galaxy. But we have no a priori reason to posit a limitation on the matter in the universe (in fact, if we were to guess at the size of the universe, it would be more reasonable to suggest the universe were infinite rather than of any particular size) and, by observation, we can establish a lower bound on the quantity of matter - that being the amount in the observable universe, which is clearly more than one galaxy's worth. So we know that there must be more than one galaxy and it is entirely possible that there are an infinite number. All of that makes it harder for us to comprehend the scale of the universe, but in no way makes the universe less sensical overall, since when the initial conditions are a particular way and acted upon by the same fundamental principles, the same result will be produced. Thus the goal in science is, through observation and experimentation, to come to an understanding of this process such that we can apply it to particular cases, but not to actually know everything there is to know about every particular thing in the universe. And it is in that way that the universe is comprehensible, whether there is one galaxy or many, as the number of particulars is for the most part irrelevant.
 
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  • #11
sophiecentaur
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Best not to ask why. lol.
I totally agree but people tend not to do what's "best". We grow up with the experience of 'someone' or 'something' being the agency for all of our early experiences. It's only natural for people and societies to come to assume that there an agency of some sort that's responsible for everything. That, to my mind, is the basic explanation for all religions and it's a very sophisticated notion that there doesn't actually need to be any one, any thing or any rule that governs everything. (It can leave you feeling totally out in the cold, which can be unsettling.)
This way of thought demands much more of my attention, I'm sure, than the vague view of the hoards of semi-religious people who basically just go along with what they've been told and sort of believe in whatever religious teaching they have been given - depending on where they live. I'd go for Bhuddism but for the fact that, down at the bottom level, they still have a column of turtles, going down for ever with some ultimate being down at the bottom.
Strange that we use Mathematics, which is a great model for most things (within its limits), and we tend actually to believe in the results it produces for us - as if Maths, itself were an ultimate truth / agency.
 
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phinds
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Strange that we use Mathematics, which is a great model for most things (within its limits), and we tend actually to believe in the results it produces for us - as if Maths, itself were an ultimate truth / agency.
Yes, lots of people forget that the map is not the territory.
 
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Yes, lots of people forget that the map is not the territory.
You mean the chart is not the manifold. :biggrin:
 
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  • #14
Klystron
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Summary:: Size of the universe

I know this question doesn’t really make sense but the absurd enormity of the universe always made my head hurt. A single galaxy alone has more then enough stars to satisfy the curiousity of any sentient being. Why 2 trillion? It’s just insane. Why did nature have to create so many? The spaces between these things are so vast; and the very laws of physics makes it impossible for anything that lives in it to travel between them. I don’t know if their is a God but I do like the idea that the universe is a living thing. It’s literally everything their is. Maybe it created itself. Who knows? I just don’t know why it has to be so big.
As Russian authors like to say, "It [the size of the Universe; distance between stellar systems] is inconvenient."

Humans, large-brained mammals that we are, look for patterns in our sensory inputs, for order, for causes that may not exist. The immense distances between cosmological objects compared to human scales requires mathematics -- not religion -- to comprehend. Creation myths remain pervasive and culturally significant but lack any basis other than wishful thinking and tradition.

When the Universe seems too large and uncaring of humans, look to the microscopic realm for comfort. If amoebas think, imagine how they envy paramecium ability to swim around their tiny 'universe' in a drop of pond water.
 
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  • #16
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I think this comes back to most humans thinking that somehow the universe was created for us when really we are a inperceptibly miniscule part of something else. My nephew hates thinking about the universe as it makes him feel insignificant......well news flash we are insignificant.

Why do we have to be significant and have a place in the scheme of the universe? Some people find this hard to grasp and strugle with their own lifes meaning of insignificance, I don't understand this viewpoint.
 
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  • #17
ZapperZ
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This thread is not about astronomy. Instead, it should be moved to "Make me feel good about myself" forum.... or "It's all about me" forum.

Zz.
 
  • #18
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2 trillion galaxies composed of a 100 billion to a trillion stars gives us 600 sextillion stars ... Our brains aren’t sophisticated enough to rationalize that number.
By that same logic, there can't possibly be 1022 transistors on the earth.
 
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  • #19
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Like all motion is relative, big is in the eye of the beholder.

We can't tell how big the universe really is, but many believe that it is actually infinite.

Do not confuse big with infinite. Nothing of finite size can ever grow to infinity, nor can anything infinite ever shrink to finite size.
Great finite/infinite quote!
 
  • #20
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Summary:: Size of the universe

I know this question doesn’t really make sense but the absurd enormity of the universe always made my head hurt. A single galaxy alone has more then enough stars to satisfy the curiousity of any sentient being. Why 2 trillion? It’s just insane. Why did nature have to create so many? The spaces between these things are so vast; and the very laws of physics makes it impossible for anything that lives in it to travel between them. I don’t know if their is a God but I do like the idea that the universe is a living thing. It’s literally everything their is. Maybe it created itself. Who knows? I just don’t know why it has to be so big.
Why does it have to be so big? Why not? Lol.
 
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  • #21
berkeman
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Thread closed. Lordy.
 
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