To have an enjoyable cosmo forum we needed a balance between mental freedom on the one hand and a shared knowledge...

Apr814 08:39 AM
Jorrie

483 
125,731 
The new A20 tabular calculator lets you look at changing geometry out to about 88 billion years according to the...

Feb814 08:31 AM
mfb

61 
23,727 
If light travels a metre in a unit of cosmological time now will it travel two metres in the same cosmological time...

May2913 08:18 AM
Naty1

13 
760 
I am a sixteen year old aspiring theoretical physicist, my dream is to actually be the one who discover the GUT(I know...

May2813 10:28 AM
Chalnoth

7 
709 
Can anybody point me to a rough calculation of the probability of a disembodied brain appearing from a random...

May2613 03:48 AM
lukesfn

2 
758 
I was reading The Elegant Universe a few days ago, and came upon a passage (p.40) where Brian Green states "Over time...

May2513 07:28 PM
Alektene

8 
626 
I've been developing an article on universe geometry that hopefully forum members will find as a useful reference,and...

May2413 05:46 PM
cristo

13 
505 
I am very new to physics and astronomy, so I don't know much, but I have a theory so tell me what's wrong with it. So...

May2413 03:26 PM
bapowell

9 
960 
Couldn't there be an equal amount of matter and antimatter in the universe. While from what I've read there is little...

May2413 10:06 AM
DrChinese

15 
1,220 
Hello folks
My name is Mike. I am into Cosmology ever since I was a kid. Throughout the years I strayed away from...

May2313 10:44 PM
Spourk

10 
1,270 
Some big names going to be at UC Davies this week for early universe conference:
...

May2213 05:19 AM
skydivephil

0 
595 
I have long been curious as to the Big Bang. Our cosmology is based on Hubble's observation of the redshift and its...

May2213 03:57 AM
DennisN

11 
945 
So, I posted this on a philosophy forum....
I was in a psychology class and I thought of something while reading...

May2213 12:47 AM
kurros

4 
768 
So two of the theories of the universe are the big rip and the big crunch or bounce. Big crunch being expansion of the...

May2113 11:10 AM
Mordred

2 
785 
Why didn't the big bang just become a black hole?
Thanks,
Jake

May2013 08:55 PM
brianhurren

51 
8,083 
I don't know whether this has much general interest. I am interested by communication horizons in cosmology, or causal...

May2013 11:31 AM
Chalnoth

11 
884 
Regarding the creation of the universe and the current model:
Is it assumed that the universe, at the time of...

May2013 01:10 AM
marcus

19 
1,416 
Hi there
Am to teach a lesson on stars and galaxies to my year 7 class on Monday...
Want to brush up on a few...

May1913 11:11 PM
Chronos

8 
753 
By quantitative cosmology I mean with real times, distances, expansion rates, horizons, CMB stationary observers etc ,...

May1813 12:36 PM
Mordred

13 
823 
Hi all,
It is my understanding that a Doppler shift is the result of a change in wave frequency due to a change in...

May1813 05:56 AM
mfb

1 
576 
I'm not a big fan of quintessence, but, this paper is interesting  Quintessence with Hybrid Potential,...

May1713 01:35 AM
Chronos

0 
595 
I have been watching Susskind's lectures on Cosmology which are great. There is something that I can't wrap my head...

May1613 08:57 PM
marcus

4 
744 
The basic equation of GR has a curvature constant Λ on the lefthand (geometric) side.
The Friedman equation is...

May1413 12:08 PM
Mordred

12 
982 
Everyday I sit and think about the universe, and after some thinking I always end up letting my imagination run wild...

May1413 09:08 AM
Forensics

6 
1,194 
Where is the edge/boundary of the universe may sound like a simple question but I can see 3 possibilities.
1...

May1313 05:09 PM
Spourk

133 
7,479 
There's a tutorial wiki for Jorrie's calculator. It needs exercises that beginning learners can do to help them get...

May1213 01:36 PM
marcus

7 
783 
Quick question: is there a general formula for the redshift zC for a photon travelled in a spacetime with arbitrary...

May1013 06:11 PM
George Jones

52 
3,813 
I tried out the new version of Lightcone today...

May1013 03:45 PM
marcus

8 
973 
In a sense the universe is its own clock and the pointerhand is the scalefactor, as in:
"when distances were 0.1...

May913 05:18 PM
Mordred

10 
1,111 
I was trying to find an updated view on the plausibility of the Big Freeze. I believe that a couple of years ago, it...

May913 06:57 AM
bapowell

2 
904 
Is it possible for technology to advance such that we can travel back in time and be the ones to set the universe into...

May813 05:13 PM
Vanadium 50

4 
847 
The first stars formed when distances were 9% of their present size.
The solar system began forming when distances...

May813 12:21 PM
Mordred

20 
1,213 
Developing a basic explanatory manual for the Light cone 1.0 calculator. This is as a supplement to give a basic...

May613 01:52 PM
Mordred

1 
579 
Hi.
I read due interest papers in Arxiv. There is many times refereed to so called NBody Simulations.
Is that...

May613 10:25 AM
phyzguy

3 
622 
http://www.youtube.com/watch?v=VZiWKmhuaZE
At about 7:00 he talked about imaginary time. Does that account for...

May513 09:24 PM
Simon Bridge

1 
754 
When the universe was young, and everything was closer together, did the extra gravity cause time to run slower than...

May513 05:48 PM
petm1

20 
1,821 
Einstein discovered that general covariance allows his GR equation to have just TWO gravitational/geometric constants:...

May413 03:32 PM
marcus

5 
844 
My question is what sort of material/matter existed to allow an expansion of the early universe?
It had to be some...

May413 03:00 PM
spark802

8 
791 
It seems as though the contemporary consensus among cosmologists is that the universe is basically flat and Euclidean:...

May413 02:11 PM
WannabeNewton

33 
1,871 
Where did scientists reach so far about this matter? Any who had rejected it?

May413 05:11 AM
M. next

11 
918 
Here is a new paper, and thorough discussion of dark matter: NonBaryonic Dark Matter in Cosmology,...

May313 07:24 PM
Chronos

6 
706 
So if there are as many galaxies in the Universe as is claimed what's the role of interstellar combination of light...

May313 07:18 PM
Chronos

6 
278 