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Show ALL Forums  > Science/philosophy  > how is the universe expanding?      Home login  
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 stargazer1000
Joined: 1/16/2008
Msg: 3
how is the universe expanding?Page 1 of 6    (1, 2, 3, 4, 5, 6)
medik, the universe is expanding. And it's not just the material in the universe, it's spacetime as well. That's an observed and observable fact.

howevever, that does not mean that there were no preconditions to the Big Bang, nor does it mean there isn't something for this universe to expand into. It's simply something that we don't have enough information to discern. Whatever exists "beyond" our universe is too far from our observational horizon to see and we don't know how preconditions might have imprinted themselves onto the fabric of our current spacetime.
 stargazer1000
Joined: 1/16/2008
Msg: 4
how is the universe expanding?
Posted: 5/1/2009 7:48:56 PM
LightStorm...hunh? Very lovely, but you didn't explain a damn thing. Sorry.
 Verzen
Joined: 12/9/2007
Msg: 5
how is the universe expanding?
Posted: 5/1/2009 8:02:23 PM
It's difficult to explain.
However, black holes and white holes work as a filtering device that recycles everything. OUR universe is expanding, but there are multiple universes. When we get an increase in blackholes, our universe will shrink and eventually die.
 FrogO_Oeyes
Joined: 8/21/2005
Msg: 7
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how is the universe expanding?
Posted: 5/1/2009 9:04:23 PM
Every element, when stimulated, gives off a characteristic light pattern. Thus, when a star burns hydrogen, viewing the light through a prism will reveal bands of different colored light, and characteristic dark bands. Those bands will always be in the same relative positions.

When light from distant galaxies is viewed, it generally appears more red, but has the same banding. We know what color the bands are supposed to be from a stationary light source. If light travels towards us while the source moves away from us, it becomes "red-shifted". The red-shift of distant galaxies shows they are moving away. This is the Doppler effect, like you would hear from any passing object, the most obvious examples being a car horn or the whine of a race car or motorcycle changing pitch as they pass.
 Go Rin No Sho
Joined: 1/9/2009
Msg: 8
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how is the universe expanding?
Posted: 5/1/2009 10:01:09 PM

and non-existence doesn't exist.


So how to black holes (in space, that is), dark stars, and the current Congress exist?
 Vancer
Joined: 10/29/2006
Msg: 9
how is the universe expanding?
Posted: 5/1/2009 10:10:13 PM
Is because empty space has no imagination and is prone to depression.
Interference, although annoying, bides energy more time before becoming chums with the big golden goose egg.
I have no idea why I said that.
 BumFluff122
Joined: 4/4/2009
Msg: 10
how is the universe expanding?
Posted: 5/1/2009 10:41:04 PM

However, black holes and white holes work as a filtering device that recycles everything.
We don't even know if white holes exist or are possibly. Physicists right now believe the universe is headed for a heat death and will never collapse in on itself because the speed the galaxies are drifting away from each other may actually be increasing and the universe is more flat as opposed to curved. That being said there is a new theory, which I completely agree with, that states that different sectiosn of the universe have actually been decelerating at different rates which would make the difference of the red shift between galaxies farther away and those in closer as understandable.
 BumFluff122
Joined: 4/4/2009
Msg: 11
how is the universe expanding?
Posted: 5/1/2009 10:43:05 PM

just because things are floating around in space means that the universe is expanding?
No. The red shift of the galaxies, the Microwave Background Radiation and a few other studies have shown the universe to have had a common origin and expanded outward.
 US_Army_Strobel
Joined: 12/3/2008
Msg: 12
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how is the universe expanding?
Posted: 5/1/2009 10:44:18 PM
Our universe started with a big bang (theoretically). What if our universe is just infinitely small material compacted in an even LARGER universe waiting for its own big bang? When our universe expands to it's limits --- BOOM!!! (Or should I say BANG!!!), another, larger universe is born? Sorry, tired, thinking VERY outside the box.
 BumFluff122
Joined: 4/4/2009
Msg: 14
how is the universe expanding?
Posted: 5/1/2009 10:58:31 PM
if everythign is moving away from us. It is expanding.
 BumFluff122
Joined: 4/4/2009
Msg: 17
how is the universe expanding?
Posted: 5/1/2009 11:16:10 PM
By planet do you mean galaxy? Yeah it's in the local group of galaxies. Our local group fo galaxies is counted as a whole region when talking about the universe expanding. And no it wouldn't mean that we are the center of the universe. Take a non blown balloon and draw 2 dots on it. They are fairly close together. Now blow up the balloon. Even though both points on the balloon are being blown out they are still both moving away from each other.

I don't know how to add pictures to this forum so I'll just post a link to it.
http://www.pas.rochester.edu/~afrank/A105/LectureXVI/FG26_005.JPG
That picture shows what happens when a balloon expands.

Earth is moving around the Sun at about 67,000 miles per hour as well as rotating and our whole solar system is moving around the center of our galaxy as well. Can you feel any of that happen? We aren't just standing still. We are always moving.
 Vancer
Joined: 10/29/2006
Msg: 18
how is the universe expanding?
Posted: 5/1/2009 11:22:43 PM
I think we are all talking about the same thing MikeB1982. We are just getting communication barriers thrown around from what words mean to us.
The universe is expanding. There is an accelerating expansion of space.

Say you had string that represented information. That string could be bundled up very tight, by subjecting it to complicated forms of interference(information redirection) that allow the string to exist in a greater spectrum of states beyond spatial dimensions. You could make it very compact, but when you throw that bundle of string into outer space, it begins to unravel towards an existence that occupies fewer state spectrums, but now more space. It is still the same amount of information, but it is expanding spatially.

I don't know if I'm wording that all right or not.
Its like the double slit experiment. The photon, when not being measured, is no longer capable of using the state spectrums that allow it to exist as a spatially compact particle. It requires a helping hand to do that. :O
 BumFluff122
Joined: 4/4/2009
Msg: 21
how is the universe expanding?
Posted: 5/2/2009 12:12:47 AM
yes. Our galaxy will crash into the Andromeda galaxy in about 3 billion years. But it is part of the local group of galaxies and are being pulled towards each other via their gravitation. Eventually they will form one galaxy.
 Vancer
Joined: 10/29/2006
Msg: 22
how is the universe expanding?
Posted: 5/2/2009 12:15:37 AM
It is both expanding and compressing in ways.
From spatial expansion in the universe, to information compression in your head.
Pick a side and maybe you'll find you are riding the craziest strange loop ever.
I really don't know. But it should be thought of as exciting rather than vexing.
 scorpiomover
Joined: 4/19/2007
Msg: 24
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how is the universe expanding?
Posted: 5/2/2009 3:57:36 AM

there can only be existence! the only other option is non-existence, and non-existence doesn't exist. So what is the universe expanding into? The only thing existence can be broken by is non-existence, and again, non-existence doesn't exist! So the universe cant expand, cause theres only ONE existence and its infinite. So how is the universe expanding?
You are right, in that the universe cannot "expand". It's a term, to reference a theory that the "known universe", the galaxies, stars and planets, are all moving further and further away from each other, as if they exploded from a big bang, expanding ever outwards. Part of that, is based on Einstein's idea, that if you travelled all the way to one end of the known universe, and kept going, that you'd just find yourself on the other end of the known universe. Of course, if you did that, then you'd be expanding the known universe, and so you could never get past the end of the known universe, so that could never actually happen. But it's just an idea, to show how gravity works to Einstein, that space "shapes" itself around masses, and makes it harder and harder to get away from them.
 scorpiomover
Joined: 4/19/2007
Msg: 25
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how is the universe expanding?
Posted: 5/2/2009 8:40:37 AM
RE Msg: 28 by bikemandarren:
Huh? That would mean the universe curves back in on itself...However measuring the background cosmic radiation shows the universe is flat and thus infinate in size...Which is another mind puzzle to think about.
The universe does curve back in on itself. Gravity gets stronger around any large planet, or star, in space. But everything appears as if you are not moving. If you started moving away from the Earth, you'd keep getting pulled back into a circular orbit, so, you'd see the Earth moving away, and then, for no apparent reason, it would appear from over the horizon. The reason is that you would think you're going in a straight line, but in reality, you'd be pulled into an orbit.

CMR (Cosmic Microwave Radiation) is different, because it has an extremely high velocity, and an extremely low mass level, compared to us. So, although we would be pulled back, the amount of force on CMR would be negligible, except in the event horizon of a black hole, which has enough gravity to affect even CMR, and this is exactly what scientists have found.
 emannigol
Joined: 2/8/2009
Msg: 26
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how is the universe expanding?
Posted: 5/2/2009 10:44:47 AM
Universe is expanding; Cosmic microwave background radiation doesn't leave much doubt.

It's proven because the spectral lines are shifted all the way to the microwave length. CMBR is pretty much the remains of the Big Bang, so the universe has been expanding from the beginning.

If universe wouldn't be expanding we should see pretty much same amount of objects getting closer and farther. However, most of the objects are showing redshift.

About the center of the universe... According to the Big Bang theory all the universe has been in an infinitely dense spot. It means that everything has been the center of the universe.

If there isn't an existence beyond the universe, it isn't expanding into anything. However, it doesn't mean it isn't expanding. It just means there aren't any edges or boundaries in the universe.
 abelian
Joined: 1/12/2008
Msg: 27
how is the universe expanding?
Posted: 5/2/2009 9:20:57 PM
Why do you think it has to be exapnading into anything? Nothing requires one manifold to be embedded into another.

You are right, in that the universe cannot "expand". It's a term, to reference a theory that the "known universe", the galaxies, stars and planets, are all moving further and further away from each other, as if they exploded from a big bang, expanding ever outwards.

WRONG. The general theory of relativity doesn't permit a stable, static universe. The cosmological constant can be used to obtain a static solution, but not a stable static solution. If there is insufficient matter to close the universe so that it contracts, it will expand. The evidence all agrees with a universe that is expanding. Not only is it expanding, but the expansion is accelerating.

 JustDukky
Joined: 7/8/2004
Msg: 28
how is the universe expanding?
Posted: 5/2/2009 9:30:31 PM
Our entire universe/multiverse could simply be a singularity and spacetime only a conventionalization that allows us to say things about it. Not that it helps much to think that "all that is" might only be a singularity. Large or small are concepts that are equally meaningless without a comparative reference. Without a yardstick to go by, any discussion of "expansion" is meaningless. All we have to compare what we see of the universe with is what is inside our corner of it so the idea of cosmic expansion is all a matter of how it looks from our perspective, which is limited and skewed at best.
 BumFluff122
Joined: 4/4/2009
Msg: 29
how is the universe expanding?
Posted: 5/2/2009 11:58:44 PM
There is a hypothesis called MOND that allows for the use of a modified Newtonian Dynamic to explain what we pbserve in the universe without adding Dark Matter. There is also a belief that sections of the universe are slowing their expansion at different rates which would allow for the observations that galaxies that are farther away are travelling faster than those closer and not need any sort of Dark Energy to explain why they are increasing in speed (Because if this is true they actually aren't increasing in speed)
 emannigol
Joined: 2/8/2009
Msg: 30
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how is the universe expanding?
Posted: 5/3/2009 1:42:19 AM

emman, it's not conclusive, the microwave background. It supports the theory, yes, but then you have to add hypotheticals that are unprovable, such as "dark energy", "dark matter" and "inflation". I like to think that any theory that requires invisible things to make it work is almost certainly wrong.


Dark energy and dark matter are only names for the unknown variables in equations. These invisible or unproven things do not disprove the fact that according to all observations the universe is expanding, and seems to be accelerating.
 chrono1985
Joined: 11/20/2004
Msg: 31
how is the universe expanding?
Posted: 5/3/2009 3:03:34 AM
There are a few things we can infer from what we can observe by looking up at the night sky.

The universe is either young (in cosmological terms), or it is not infinite. The proof being that light travels, stars live for long periods of time, if the universe was old or infinite in it's existence, there would not be any darkness between the stars. Through measuring the weights of elements and understanding the process in which they form, we can safely assume it is relatively young, infinite or finite however can't be assumed so easily.

The universe has no concept of existence as we do. From measurements taken both near Earth and far from it through telescopy and radioscopy, we find that matter is sparsely distributed into pockets. These pockets get lots of names, planets, solar systems, galaxies, clusters, so on and so forth.

Gravity is the thing keeping it all together both microscopic and macroscopic. While this has and is contested on a regular basis, it's held up for quite a long time now (in human terms of time). Since gravity is just a function of mass affecting other mass I think, but am not sure, it's the matter that makes what we know as existence, that there is no edge of existence unless you measure existence as the area where matter is present, in which case there's more non-existence than there is existence in the known universe, but moving into such non-existence areas would be taking existence with you into those areas.

There is however the end-condition. Using just the force of gravity itself it's entirely possible to accelerate a body of mass into escape velocities (velocity that is required to escape a field of gravity). That suggest that eventually through sheer random chance alone, mass will reach those escape velocities to spread itself so thin that the heat required for the universe to exist as it is today will not be possible. This is what is known as the expanding universe in the easiest terms I can think to explain it, it results in a deep cold.

There's also the opposing end-condition. Gravity will force all matter into a single point in space, what happens then is purely speculation as we have no basis for comparison outside of theoretical terms. This is what is known as the collapsing universe, it results in heating (from friction) on magnitudes of the likes we can't even begin to imagine.
 emannigol
Joined: 2/8/2009
Msg: 32
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how is the universe expanding?
Posted: 5/3/2009 10:01:43 AM

Indeed, if you want to abstract like that, that's fine. But then in this context my point is that we keep having to add new variables! Something is clearly wrong, don't you agree?


I don't see anything wrong, because that's how mathematical and physical problems are solved. Most of us have probably learned this from school.

We place all known variables into an equation. If it doesn't still work after other posibilities for an error have been excluded; there must be an unknown variable x involved. In fact it's possible to calculate the effect of that variable.
 BumFluff122
Joined: 4/4/2009
Msg: 33
how is the universe expanding?
Posted: 5/3/2009 2:43:14 PM
I'm sure everyone has seen the picture of the Hubble deep field study. The Hubble telescope was aimed towards a small, apparently completely black piece of space and was held there for, I believe, a couple months to take in all the light it could. The outcome was what we see in this image:

http://www.sciencemusings.com/blog/uploaded_images/HUDF-777866.jpg

Every single one of those points are galaxies that the human eye can not see because they are far to dim. However the light from them is still hitting Earth.
 Vancer
Joined: 10/29/2006
Msg: 34
how is the universe expanding?
Posted: 5/3/2009 3:42:17 PM
Infinity wouldn't necessarily require infinite space.
The storage room need only be big enough to accommodate an infinite amount of states, including what it takes to have space, time, blue, red, happy, sad, egg salad and toast, if it has to. It might require far less space in systems which get better at creating new states of existence.

I have no idea what I mean.
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