Discussion in 'Astronomy, Exobiology, & Cosmology' started by wegs, Jul 16, 2022.
I’ve wondered this, too. You should ask that in the UAP thread.
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This is what I used for finding M31.
In my comments here I was thinking about M13.
If anyone wants a good (free) program for knowing what the sky looks like real-time check out Stellarium.
This was years ago, I looked and looked with my scope, but could never claim M1. It was just a cheap 60mm refractor. I can not find my notebook. I think I claimed about 70 or 80 M objects.
With Andromeda, I've read if you could visualize the entire thing with the naked eye, it would be six times the size of the moon, so we're only able to see the center portion.
This may seem like a random (potentially naive) question, but is there any ''center point'' in space?
Why? If the universe is thought to be infinitely expanding, is that the reason?
The universe is not an expansion into space; it is an expansion of space.
There is no boundary - no edge.
There is no place in the universe where you're close to an "edge", so all points are equitable.
It's not an easy concept to grasp in three dimensions, but it's easy to grasp in two.
Imagine being a 2-dimensional creature who lives on the surface of an expanding sphere. Your world is the surface, not the interior. Your world is expanding: every point is getting farther from every other point, but there is no "centre" - no special point from which all others are expanding.
Our universe is the 3D equivalent.
The Big Bang didn't start from some center point and then expand out from that. As Dave says, all points in space are expanding. The BB wasn't an explosion. It was a small "dot" that is now a large and continually expanding "dot". If it is infinite (don't know for sure) then it was always infinite. It's just bigger now.
This isn't a perfect analogy but where is the center of the surface of the Earth? There isn't one. Blow a balloon up and where is the center of the surface? There isn't one. All points are expanding equally.
Regarding infinity, no one knows. I tend to think it's not infinite but it also becomes a matter of definitions as well.
However all that we know for sure is what we see in the visible Universe. It appears to be flat but there is a lot more to the Universe than the visible Universe. It could be so big that the flatness is just an appearance but not reality. The Earth isn't flat but the road outside your house appears to be flat. It's only on a much larger scale that we see that it is curved.
The Universe is either flat or it is so much larger than the visible Universe that it only appears to be flat. If it is flat then logic dictates that it is infinite (I think).
I do understand that it's an expansion of space, but perhaps I was thinking that there is/was a single point...somewhere. At first, I had thought the location of the Big Bang could serve as this ''starting point'', but the Big Bang caused the entire universe to come into existence all at once.
Do you believe that the universe is infinite, or that it's finite (yet unfathomably larger) than we'll ever be able to see?
Looks like we were thinking along the same lines, Seattle...typing at the same time. Please Register or Log in to view the hidden image! Thanks to all who are taking the time to patiently answer my questions.
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At first, I had thought the location of the Big Bang could serve as this ''starting point'', but the Big Bang caused the entire universe to come into existence all at once.[/QUOTE]
A central point would imply an outer edge. That would imply a planet around a star somewhere whose sky is half full of stars and half ... what? empty?
Personally ? I have a hard time with infinity.
If I were to put money on it, I suspect that if we flew in one direction long enough, we would arrive back in familiar space. Just like what happens if you walk around the Earth.
Frankly, it's the raison d'etre for hanging out on such forums.
I have a problem with infinity as well particularly the concept which would derive from that about every possible combination existing out there somewhere such as exact versions of you and Earth and every possible permutation. I just don't buy that.
I think it doesn't really matter as a practical matter since the visible Universe is more than we'll ever cover. Infinity just strikes me as a mathematical concept only.
That's how my dad explained it to me when I was about 8 years old. (Mid 1960s). Still resonates with me.
It would imply that the universe started from one, single point...then it would have a center.
The more I've been reading about the possibility of a finite universe, the more that makes sense. But our observable universe seems infinite, so I guess we'll never really know.
Yeah. I read an article in SciAm that was able to calculate just how far unique space would go before it would have to start repeating "me" or "we".
It's admittedly a huge number, but it's not infinity.
To a butterfly the Universe is infinite I'm surePlease Register or Log in to view the hidden image!
I think some of these questions become meaningless depending on how you define them. I think of the Universe as encompassing everything. If you start talking about multiverses then you are changing the definition of Universe in my book.
You can talk about "something from nothing" but in quantum mechanics there are quantum fluctuations even where there is "nothing" or rather there never is "nothing" so again, it all depends on the definitions.
Therefore I think it's not worth worrying about in a sense.Please Register or Log in to view the hidden image! Just follow the knowledge as we develop it.
When we're talking about the scale of space, we might as well consider butterflies and human beings to be approximately the same size.
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