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Quality answers to common cosmology questions
Jul23-14 11:07 PM Greg Bernhardt 
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Jan16-12 Greg Bernhardt
To have an enjoyable cosmo forum we needed a balance between mental freedom on the one hand and a shared knowledge...
Aug2-14 07:51 PM
493 165,592
The new A20 tabular calculator lets you look at changing geometry out to about 88 billion years according to the...
Jun11-14 11:00 AM
65 44,675
Not that it has become so small it is undetectable; but the point from which it was emitted is such a distance away...
Mar23-11 07:41 AM
7 1,517
We know that the particles in the hot universe obey Fermi/Bose statistics, but when we calculate the scalar dynamics...
Mar23-11 02:42 AM
1 1,117
The word 'cosmos' is defined as an orderly harmonious systematic universe. There are some people who actually think...
Mar22-11 01:19 PM
6 3,039
Just reading the Physorg article on the new numbers on the expansion of the universe. While sipping my coffee a...
Mar22-11 12:42 PM
10 1,633
I have seen a few other similar posts but wanted to add my thoughts. Is gravity the space between bubbles of dark...
Mar21-11 04:42 AM
9 2,876
You know how the lambda constant just grew exponentially in the first second of the universe? That was just a...
Mar20-11 04:42 PM
4 1,330
Assalamualykum Iím a non-math person, but that doesnít deter me from being logical and rational who churns out...
Mar20-11 07:20 AM
20 3,002
I was reading about the VSL theory as an alternative solution to inflation that solves the horizon problem. My...
Mar19-11 03:16 AM
5 1,100
Does this question have an answer? Does the beginning of time coincide with the Big Bang? Is it appropriate to ask...
Mar17-11 09:50 PM
98 73,213
How was the big bang possible considering the 1st law of thermodynamics. Was all energy and matter created during the...
Mar17-11 02:45 PM
2 1,433
The title says it all. With all that mass in such a small space it must have been one, but then everything would have...
Mar16-11 07:58 PM
43 6,723
Sometimes we need to calculate the evolution of the scalar field \phi with the equation of motion \frac{\partial^2...
Mar16-11 05:57 PM
10 1,867
Usually at first, when trying to understand what universe expansion is, one asks: what is the universe expanding...
Mar16-11 11:25 AM
29 4,268
I hear a lot about astronomers using type IA supernovae to accurately measure large scale distances over billions of...
Mar16-11 03:48 AM
4 2,305
Dark Energy Cosmology makes the front page again: In a new study, a team of researchers led by Adam Riess of the...
Mar16-11 02:05 AM
1 890
Hi everyone, First time posting, sorry if this is in the wrong format or wrong place. For a project in a cosmology...
Mar16-11 12:40 AM
5 2,003
Mar16-11 12:13 AM
1 835
In the following video Penrose states that the Universe was so special and organized at its initial state the figure...
Mar15-11 10:43 PM
2 1,635
Shot in the dark here, don't really know if these exist. 1. An idea that time would run backward if the universe...
Mar14-11 09:45 PM
Beer w/Straw
3 1,077
If there is duality, at the big bang, when matter and antimatter was created, why did the balance shift to matter?...
Mar14-11 01:36 PM
3 1,886
Dear All As I have understood, there will be only cooling chunks of matter like stray planets, neutron stars, brown...
Mar14-11 12:16 PM
7 1,193
I have only a basic understanding of science, but don't the Second Law of Thermodynamics and the concept of entropy...
Mar14-11 03:45 AM
15 2,316
Greetings, I read a lot. It is often repetitious. Occasionally I read an idea or way of looking at something that I...
Mar13-11 09:45 PM
4 1,255
I don't know much about the big bang but if there was an explosion and the universe started expanding from a small...
Mar12-11 02:48 PM
12 1,447
Greetings, Is space made up of individual units like pixels on a computer screen? And the amount of space in the...
Mar12-11 08:56 AM
7 1,361
Is it possible to define a maximally rotating black hole? Could it be: 4\alpha^2 = r_s^2 (i.e....
Mar11-11 08:41 PM
10 2,752
is antimatter the same thing as dark matter? is antigravity the same thing as dark energy?
Mar11-11 01:26 PM
13 1,605
I wonder if someone has ever considered the following scenario: 1. "Standard" Big Rip model (phantom...
Mar11-11 05:21 AM
11 1,556
Now I'm using p=3H^2/8piG and I have H=70 km/s/Mpc, what is the critical density of the universe? now I'm plugging...
Mar10-11 08:35 PM
1 4,392
I know that H(t) = 1/a(t) x da/dt I know that a(t) is proportional to t^2/3 and da/dt is proportional to a^-1/2...
Mar10-11 08:14 PM
1 1,159
Can the speed at which galaxies separate exceed the speed of light?
Mar10-11 05:43 PM
5 1,308
Can someone give a clear definition of what we mean when we say the CMb spectrum is adiabatic and what it means for...
Mar10-11 08:25 AM
5 795
Wondering if anyone can help. Is there likely to be any difference in the gravitational properties of an event horizon...
Mar10-11 01:11 AM
19 3,021
Greetings, #1 - If all matter energy, and space were concentrated at the big bang, and the universe has been...
Mar9-11 10:16 PM
21 3,564
Greetings, The answer to a major question has raised another problem...then solution...then questions. Why...
Mar9-11 06:09 PM
2 805
First of all I'm a physics n00b so forgive me for intruding upon you people, whom I consider to be the pinnacle of...
Mar9-11 05:59 PM
2 788
Here is my understanding of how the anisotropies of the CMB are used to determine the geometry of the universe: The...
Mar9-11 07:04 AM
5 4,514
An estimate of 0.94/tPlanck for the maximum reached by the Hubble parameter was given by Ashtekar and Sloan here...
Mar9-11 05:13 AM
16 2,622
I know that the issue of cosmological redshift has been discussed in this forum before, e.g. click here, but I would...
Mar8-11 03:38 AM
9 2,487
In his theory, Stephen Hawking suggests that a black hole will give off thermal radiation. Radiation is light, so how...
Mar6-11 04:45 PM
2 1,656

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