Light years?

Seattle said:
M31 is frustrating to me too. That's a matter of light pollution for me. You locate Hercules and it's a "box" but these days in Seattle even Hercules is hard to pick out due to light pollution. Once you find it M31 is on the right vertical side closer to the top than to the bottom.

I used to be able to find it pretty easily but now there is just too much light pollution. To see M31 I would need to use my telescope or my binoculars but it's much harder to pick out these days. When you do see it, like much of astronomy, you see it by not looking at it. :) You use the rods rather than the cones so an indirect gaze is what works. That's annoying of course.

If you have binoculars and you are frustrated with not being able to find/see M31 or Andromeda try the Pleiades and the Orion Nebula. You will see those with binoculars without having to gaze indirectly or wonder whether you are seeing it or not.

Even astronomy is frustrating and is a matter of managing expectations. It becomes more interesting when you combine what (little) you can see with what you have learned from reading. You can look at a star and it's boring unless its a different color or a binary star but if you've read about the life cycle of stars, how they are formed, or something unique about that particular star then it's interesting.

If you haven't done the research and are just looking at that dot of a star it's not too interesting. If you know how many planets are around it, how fast it's spinning, how large it is or how far away combined with locating it, it's a little more interesting.

Jupiter and Saturn are the no-brainer objects for any small telescope. Jupiter more so because of the 4 major moons that change position enough to notice, on a hourly basis. Saturn is impressive just because of how "alien" it looks even though it's very small though an amateur telescope but it is distinctive. Most people feel some sense of awe the first time they see it though a small telescope.
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In my comments here I was thinking about M13.
 
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.
 
Sarkus said:
There are a handful of galaxies that you might be able to observe with the naked eye. If you knew where to look. And what to look for. And don't mistake it for just another blurred light in the sky. :)
Andromeda, our closest spiral galaxy, is one such. The Megellanic Clouds are another.
You wouldn't be able to discern stars within those galaxies, though, so if you know you're looking at a star it is one within the Milky Way.
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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?
 
wegs said:
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?
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No.
 
wegs said:
Why? If the universe is thought to be infinitely expanding, is that the reason?
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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.
 
wegs said:
Why? If the universe is thought to be infinitely expanding, is that the reason?
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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).
 
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DaveC426913 said:
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.
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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. :smile: Thanks to all who are taking the time to patiently answer my questions.
 
wegs said:
I do understand that it's an expansion of space, but perhaps I was thinking that there is/was a single point...somewhere.
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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?


wegs said:
Do you believe that the universe is infinite, or that it's finite (yet unfathomably larger) than we'll ever be able to see?
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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.
 
DaveC426913 said:
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.
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.
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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.
 
DaveC426913 said:
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.
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That's how my dad explained it to me when I was about 8 years old. (Mid 1960s). Still resonates with me.
 
DaveC426913 said:
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?
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It would imply that the universe started from one, single point...then it would have a center.

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.
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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.
 
Seattle said:
...every possible combination existing out there somewhere such as exact versions of you and Earth and every possible permutation.
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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 sure:)

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.:) Just follow the knowledge as we develop it.
 
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