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#1
11-01-2003, 10:11 AM
 shea241 Guest Join Date: Jul 2002 Posts: 86
if you were to squash the unviverse back into a singularity

ok the mass of the universe is estimated by some people to be
3 x 10^55 g

http://curious.astro.cornell.edu/que...php?number=342

if you were to squash the unviverse back into a singularity how far would the event horizion extend out to.
#2
11-01-2003, 10:46 AM
 Redsland Guest Join Date: Feb 2001 Location: Yonder Posts: 280
If the three spatial dimensons of the universe were compressed into a singularity, there would be no space for an event horizon to reside in.
#3
11-01-2003, 10:51 AM
 shea241 Guest Join Date: Jul 2002 Posts: 86
How is that possible doesn't that mean that the light and everything else would just escape and the universe would expand?
#4
11-01-2003, 11:11 AM
 MC Master of Ceremonies Guest Join Date: Nov 2002 Location: The 2nd corner Posts: 3,020
If you want to know, the radius of the event horizon of a black hole of mass 3 x 105 kg, well that's easy, it's about 4.4 x 1028 m which is roughly 5 trillion light years (barring silly mistakes in my calculations)

Of course it's not that simple, the big bang singularity is not the same as ones that occur in a black hole.
#5
11-01-2003, 11:15 AM
 Squink Guest Join Date: Oct 2000 Location: Yes Posts: 20,327
Quote:
 The basic idea is that the radius of a black hole is that distance from the center where the escape velocity is equal to the speed of light. This is known as the Schwarzschild Radius. It can be calculated from the following equation:R = 2*(GM/c^2) In this equation, G is the gravitational constant, M is the mass of the original object, and c is the speed of light.
http://www.windows.ucar.edu/tour/lin....html&edu=high

G = 6.67259 *10-11 m3 s-2 kg-1

So R = 2 * M * 6.67259 * 10-11/9* 1016
R = M * 1.482 * 10-27
R = 3 x 10^52 * 1.482 * 10-27
R = 4.448 x 10^25 m
-
R = 4.736 x 10^9 light years
-Assuming no math errors.
#6
11-01-2003, 11:20 AM
 Squink Guest Join Date: Oct 2000 Location: Yes Posts: 20,327
Uh oh. Someone's got an error here.
Regardless, the initial singularity may have been considerably less massive.
#7
11-01-2003, 11:24 AM
 MC Master of Ceremonies Guest Join Date: Nov 2002 Location: The 2nd corner Posts: 3,020
Oops, I see; the value was in grammes not kilograms.

(also as a correction to my last post that should of been 3 to the 55, not to the 5).
#8
11-01-2003, 11:28 AM
 Exapno Mapcase Charter Member Join Date: Mar 2002 Location: NY but not NYC Posts: 29,300
Quote:
 Originally posted by shea241 How is that possible doesn't that mean that the light and everything else would just escape and the universe would expand?
Escape into what? By definition the universe is everything. If you squash it down into a point, then you are squashing the light and every other particle into that point. There is nothing outside that point for the light to escape into.
#9
11-01-2003, 12:22 PM
 shea241 Guest Join Date: Jul 2002 Posts: 86
then is it possible that the universe isn't expanding but that everything within the universe is contracting?
#10
11-01-2003, 12:44 PM
 MC Master of Ceremonies Guest Join Date: Nov 2002 Location: The 2nd corner Posts: 3,020
Quote:
 Originally posted by shea241 then is it possible that the universe isn't expanding but that everything within the universe is contracting?
'Tis interesting that you should say that as emminent cosmogist and big bang rejectionist Fred Hoyle helped to show that a universe with everything in it shrinking produces the same results as a big bang csomolgy, this was known as variable mass theory). Though it was formulated a while ago and I doubt that it could explain everything in cosmology as it is these days.

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