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Theoretical Physics Thread

 
 
Reply Sun 4 Jan, 2004 03:09 am
This thread is for discussing all manners related to physics theory...

Ex: wormholes, big bang, time travel, curvature of the universe, theory of relativity, uncertainity principle, antimatter, dark matter, nuclear fusion, celestial bodies, quantum physics, string theory, parrallel dimensions, the concept of time, and the fate of the universe...

I'll get this started...

Fate of the universe, there are a few variations on two prominent possibilities...

heat death...
The universe has sufficent mass that it is expanding at a rate faster than gravity can ever over come (as the universe expands more, the force of gravity decreases exponentially). Eventually, all matter will be converted to energy and all energy converted to it's lowest form, heat. The universe will be a vast empty place. Unfortunately, current estimations as to the size and mass of the universe point to this possibility Crying or Very sad .

the big crunch...
The universe has sufficent mass that gravity will eventually overcome it's rate of expansion and the entire universe will be pulled back in together into a big crunch. Another singularity will reemerge. Eventually, the density of matter in this singularity will be such that strong nuclear force will be overcome. The universe once again explodes outward in an array of matter and antimatter known as yet another big bang, another beginning. One addendum to this theory is that all singularities before they achieve critical mass are identical. Thus the next big bang will be identical to the previous, matter will be distributed in the same way, life will form in the same way. Everything will happen again exactly as it has already. History will repeat itself. Of course, this addendum (my personal favorite) requires a belief in determinism.

But perhaps, humanity's potential will grow so significant that humans will not only colonize planet's throughout the universe but will find ways to circumvent seemingly absolute laws of physics to prevent both the heat death and the big crunch and thus grow and prosper for eternity.

By far the coolest article for anyone interested in physics. Credit to fresco for finding it.
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Type: Discussion • Score: 2 • Views: 2,217 • Replies: 20
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Wilso
 
  1  
Reply Sun 4 Jan, 2004 05:09 am
All too much for this mind. I have enough trouble with F=ma.
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littlek
 
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Reply Sun 4 Jan, 2004 10:25 am
Hmmm, I find the ultimate fate of the universe to be outside my realm of interest. I'm more interested in dark matter, string theories, and celestial bodies.
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cavfancier
 
  1  
Reply Sun 4 Jan, 2004 10:48 am
Mmmm....celestial bodies...<drools> Oh, wait, I thought this was the sex talk thread. Oops.
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Centroles
 
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Reply Sun 4 Jan, 2004 01:32 pm
we can talk about those topics as well.

hasn't dark matter been proven not to exist?
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dlowan
 
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Reply Sun 4 Jan, 2004 01:38 pm
timid bookmark
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Centroles
 
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Reply Sat 17 Jan, 2004 07:00 am
no physics buffs in here?
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Terry
 
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Reply Sat 17 Jan, 2004 11:19 am
Since the expansion of the universe seems to be accelerating, the big crunch ain't gonna happen.

Where did you get the idea that dark matter was proven not to exist? It is still thought that dark matter makes up 23% of the universe, 4% is ordinary matter, and 73% dark energy.
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TripleM
 
  1  
Reply Sat 17 Jan, 2004 01:38 pm
I have always been fascinated by the number of dimensions of this universe. Some say 10, others say 26. So what say you?
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Relative
 
  1  
Reply Mon 2 Feb, 2004 03:17 pm
Quote:
I have always been fascinated by the number of dimensions of this universe. Some say 10, others say 26. So what say you?


Some suggest even up to 42 Laughing

When I last looked, they were searching for curled-up extra dimensions, that may be detectable. I guess no luck so far Sad

Maybe 3 dimensions are the best - I somehow like the idea of 'evolution of universes' - that is, universes with different number of dimensions, different physical laws even, are constantly born - and many of them don't exist long enough to be observed (by sentient beings - us). The fact that we are discussing this now makes our universe a good one :wink:

Of course, we may never know if there are any other universes, unless we are the Observers that are placed inside Universes to decide their quality, and then re-incarnate in another universe..
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Gcam
 
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Reply Mon 2 Feb, 2004 06:47 pm
As far as my understanding goes, it's thought likely that there are an almost infinate number of parallell universes out there. It's thought that every single fundamental event in the universe (ie whether the smallest subatomic particle lives or dies) results in 2 new universes, one in which the particle exists and one in which it doesn't. This would create an infinate number of universes in which every single possible outcome of every single situation is embodied in a seperate universe. Very interesting, and very deep...
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Brandon9000
 
  1  
Reply Tue 3 Feb, 2004 10:57 am
Although I have some training, this is over my head, but I do remember that early string theories had a model in which the universe had ten dimensions, nine of space and one of time.

I think the previous poster is referring to the Many Worlds Interpretation of quantum mechanics, which is a popular successor to the traditional Copenhagen Interpretation.
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jeraldz
 
  1  
Reply Thu 5 Feb, 2004 08:02 pm
what is resistor in series?
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Relative
 
  1  
Reply Thu 5 Feb, 2004 08:17 pm
Hi jeraldz and welcome!

But I don't know what you mean by resistor in series?
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Wilso
 
  1  
Reply Thu 5 Feb, 2004 08:26 pm
jeraldz wrote:
what is resistor in series?


Is this a question referring to this thread or on it's own. If you're talking about electronics, then resistors connected in series are those connected end to end in a line.

----------
If each dash is a resistor, these are connected in series.

_
_
_
_

These would be connected in parallel
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neil
 
  1  
Reply Fri 6 Feb, 2004 02:31 pm
Wilso did a good illustrartion, but he switched the labels. The current flows through each series resistor sequentualy = one after an other = all the electrons go though each resistor. In a series of resistors the voltage divides proportional to the resistance. The sum of the voltages around a series circuit = zero if we include the voltage source with the opposite sign. The combined resistance of series resistors is the sum of the individual resistance. Thank you for moving the subject from science to engineering
If the center of a planet such as Mars or of a moon such as Earth's moon is 932 degrees f = 500 degrees c = 773 degrees k, the temperature will drop slowly as you move toward the surface, because heat is being radiated into space. There will be a broad band where water is a liquid. The pressure may be high enough to prevent the water from boiling even at the center. These bodies may have more liquid water than Earth in the cracks and under ground caverns, unlike Earth which has steam with no liquid water more than about 20 kilometers below Earth's surface because Earth's center is about 3 ? times hotter in K degrees. Please embellish, refute, or comment. Neil
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Relative
 
  1  
Reply Fri 6 Feb, 2004 03:36 pm
neil, could you support your theory with some numbers?
Especially the range of temperature&pressure areas of liquid water. Also, the Earth is actively heated because of radioactive decay & geological activities that cause friction.
Moon is geologically dead, and Mars is extremely inactive. I am not sure what are the estimates of temp. of inside the planet, and how does it fall off towards the surface. I agree that there may be liquid water if conditions are just right.
I believe there is some speculation whether there is liquid water several meters below the surface.
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Wilso
 
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Reply Fri 6 Feb, 2004 03:58 pm
I didn't switch the labels. The labels are below each diagram!
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neil
 
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Reply Sat 7 Feb, 2004 10:33 pm
Hi wilso: Now I see below lables are correct. Neil
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OCCOM BILL
 
  1  
Reply Sat 7 Feb, 2004 10:54 pm
Bookmark
0 Replies
 
 

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