Where is the center of the universe?


by JediSouth
Tags: universe
Tanelorn
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#181
Feb12-12, 01:18 PM
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Well I thought you or the others were having a dig at me for using the term imagination in a science related discussion.

I dont think I would want to manage a Hilbert's grand hotel, it would mean an infinitely bad headache every time a new guest walks in. Is the Universe actually a Hilbert Hotel? Its giving me a headache :)
ynot1
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#182
Feb12-12, 05:04 PM
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Quote Quote by Tanelorn View Post
Well I thought you or the others were having a dig at me for using the term imagination in a science related discussion.

I dont think I would want to manage a Hilbert's grand hotel, it would mean an infinitely bad headache every time a new guest walks in. Is the Universe actually a Hilbert Hotel? Its giving me a headache :)
I'll admit it would have to have a rather large parking lot. But I don't think the universe is really infinite like a Hilbert hotel. More like finite unbounded. Maybe a regular hotel with no borders around it? <[:>)]
Tanelorn
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#183
Feb13-12, 08:31 AM
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Its all good.

This JWST should help answer a few questions and maybe raise a few more.
I discovered this FAQ which shows how well it is expected to perform. Just have to still be around in 5-10 years to see the results:

http://www.jwst.nasa.gov/faq.html#howlong


I wonder if a future successor to the JWST might benefit from being beyond the solar system completely?
ynot1
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#184
Feb13-12, 10:18 AM
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Quote Quote by Tanelorn View Post
OK I would like to remove all instances of imagine from my posts on this thread and instead use terms like visualize.
I agree that infinity cannot be visualized - except by a mind of infinite size taking an infinite time! Other good words are thought experiment, postulate, speculate, premise, conjecture etc.
Terms like imagination are not very acceptable even if you are using a little!
Terms like imaginary, as in imaginary numbers, do seem to get into the lexicon.
Drakkith
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#185
Feb13-12, 07:19 PM
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Quote Quote by Tanelorn View Post
I wonder if a future successor to the JWST might benefit from being beyond the solar system completely?
Other than reduced heating by the sun, which is worked around by cooling the telescope, I don't really see any benefit. It would be far more expensive to send it beyond the solar system than to just load it up with coolant. Plus once it's beyond about Mars or Jupiter solar panels are no longer an effective means to provide power, meaning you need an Radioisotope Thermoelectric Generator. Also you would have to increase the size and power requirements of the antennas in order for the signals to be sent and received between Earth and the telescope.
phinds
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#186
Feb13-12, 07:24 PM
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Quote Quote by ynot1 View Post
So the more telescopes or other space probes we build the larger the universe becomes.
So you think if we build more and bigger and better telescopes, the observable universe will become bigger? Or is it that the entire universe will become bigger? I don't get how our building telescopes has any effect on either.
Drakkith
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#187
Feb13-12, 07:27 PM
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Quote Quote by phinds View Post
So you think if we build more and bigger and better telescopes, the observable universe will become bigger? Or is it that the entire universe will become bigger? I don't get how our building telescopes has any effect on either.
I think he means that in the view of whatever philosophers he was referring to, the more we see the more exists. Not in the sense that the diameter of the observable universe becomes larger, just in that the more we look at the more exists and the more detailed it becomes. But this would raise a million more questions in my mind, so I don't agree with it.
Genx63
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#188
Feb15-12, 04:36 PM
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first you say the universe spread out from a single point and then you say that point don't exist. I don't buy the ballon analogy. That would indicate that all matter is spreading out on a 2 dimensional plane. When a star goes supernova does the star all of a sudden not exist? Why is everyone so dead set against a point of origin for the universe? Maybe it's because it would punch too many holes in your theories. I'm no genius I'm not even very smart but even your balloon theory has a center.
minio
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#189
Feb15-12, 04:39 PM
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Balloon analogy is called analogy because it is not exact description. For start try to imagine that balloon has 3D surface and its expadnig in 4D space.
Spourk
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#190
Feb15-12, 05:05 PM
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Quote Quote by Genx63 View Post
first you say the universe spread out from a single point and then you say that point don't exist. I don't buy the ballon analogy. That would indicate that all matter is spreading out on a 2 dimensional plane. When a star goes supernova does the star all of a sudden not exist? Why is everyone so dead set against a point of origin for the universe? Maybe it's because it would punch too many holes in your theories. I'm no genius I'm not even very smart but even your balloon theory has a center.
Do a google search for Hypersphere. You're not quite grasping the balloon analogy the way it's meant to be presented, if you are still trying to say there is a center of the balloon. A hypersphere is a little easier to look at and see how you can actually travel and never reach a center, or an edge, it just keeps looping back on itself in higher dimensions.

Try this thought experiment: If you were 1 dimensional, and lived on the outside of a circumfrence of a circle, where would the center be? As a 1 dimensional being, you can only traverse the line on the outside of the circle, you'd never be able to reach the "Center" because that is in the 2nd dimension. You could go forward, or back, nothing else. Where is the center?

That being said, how well did the "Earth is the center of the universe" theory work out for Cosmology?

(Forgive me if this has all been presented to the OP already)
Drakkith
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#191
Feb15-12, 05:08 PM
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Quote Quote by Genx63 View Post
first you say the universe spread out from a single point and then you say that point don't exist. I don't buy the ballon analogy. That would indicate that all matter is spreading out on a 2 dimensional plane.
Of course. That's why it's and analogy. Extrapolating the same principles into 3 dimensions instead of two would give us a hypersphere. Currently the standard model doesn't care whether we are on an actual hypershpere or not, it simply says the universe is expanding.

When a star goes supernova does the star all of a sudden not exist?
The material that made up the star still exists. Whether you could call it a star or not is debateable.

Why is everyone so dead set against a point of origin for the universe? Maybe it's because it would punch too many holes in your theories.
You are correct. A point of origin for the universe would be a big glaring hole in our current model of the universe. A model which is the best fit to observations and theoretical work by far. Punching holes in the theory is akin to not believing gravity exists and saying that fairies hold everything together. You would have to make up stuff that isn't even observable in both cases.

I'm no genius I'm not even very smart but even your balloon theory has a center.
It isn't a theory, it's an analogy. A way to visualize and a tool to help people understand the basic concepts. Don't take it for more than it is. Arguing against it is like arguing that students shouldn't start learning physics with blocks sliding on frictionless surfaces because they don't exist. They do that because it's easier to learn the basics that way.
ynot1
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#192
Feb15-12, 10:22 PM
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Quote Quote by phinds View Post
So you think if we build more and bigger and better telescopes, the observable universe will become bigger? Or is it that the entire universe will become bigger? I don't get how our building telescopes has any effect on either.
Yes the observable universe becomes bigger. Point being you can observe more with better telescopes. Why would the universe get bigger, except for expansion?
Drakkith
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#193
Feb15-12, 10:26 PM
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Quote Quote by ynot1 View Post
Yes the observable universe becomes bigger. Point being you can observe more with better telescopes. Why would the universe get bigger, except for expansion?
The observable universe wouldn't increase in diameter no matter how many telescopes we built or how big we built them. We simply can't see past a certain point because there isn't anything to see.
ynot1
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#194
Feb15-12, 10:42 PM
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Quote Quote by Drakkith View Post
The observable universe wouldn't increase in diameter no matter how many telescopes we built or how big we built them. We simply can't see past a certain point because there isn't anything to see.
Certainly. I should have said the observed universe. Maybe a distinction without a difference?
ynot1
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#195
Feb15-12, 11:13 PM
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Quote Quote by SHISHKABOB View Post
would it be that there is no center or that every point is the center? Or is there a difference between those two?
I can define the center of a circle - every point on the circle is equidistant from the center - pick the closest one. I presume such can be said of a sphere except you only have one choice. But there is no point equidistant from every point on the surface of the earth, as well as the universe, ergo the earth and the universe technically have no center according to my understanding of the definition of center. This assumes the universe has a surface, but that is debatable.
Drakkith
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#196
Feb16-12, 12:25 AM
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Quote Quote by ynot1 View Post
Certainly. I should have said the observed universe. Maybe a distinction without a difference?
Certainly as we get more telescopes and they get bigger and better we will be able to see dimmer objects or get better resolution, but I wouldn't say the observed universe becomes "bigger". But I'm not one of those philosophers you were talking about either.
ynot1
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#197
Feb16-12, 07:21 AM
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Quote Quote by Drakkith View Post
Certainly as we get more telescopes and they get bigger and better we will be able to see dimmer objects or get better resolution, but I wouldn't say the observed universe becomes "bigger". But I'm not one of those philosophers you were talking about either.
I meant the telescopes get bigger, not the universe.
phinds
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#198
Feb16-12, 07:25 AM
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Quote Quote by ynot1 View Post
Yes the observable universe becomes bigger. Point being you can observe more with better telescopes. Why would the universe get bigger, except for expansion?
So, you figure that when folks learned how to sail around the world, and could therefore see more of it, it got bigger?

I think you misunderstand the term "observable universe". It is NOT based on what we CAN see, it is based on what we COULD see, and it is at present 13.72billion light years in radius and if we had the most amazingly wonderful telescopes that could possibly be built, and that could see throughout the electormagnitic spectrum, it would STILL be 13.72 light years in radius.


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