The tag has no wiki summary.

learn more… | top users | synonyms

17
votes
2answers
347 views

How would the night sky appear at the edge of the galaxy?

In Isaac Asimov's Foundation Series, there is a planet named Terminus which is believed to be the planet farthest from the galactic center. There are almost no visible stars in its sky, only the ...
8
votes
8answers
392 views

As the universe ages, will we see more stars or less?

After a very long time will we see more stars (due to the fact that more light is get to us) or less stars (as the universe expends and light have to pass larger distance)? In general, can stellar ...
5
votes
2answers
585 views

Planck satellite 2013 results impact on cosmological models

I've recently watched a "Through the Wormhole" episode from 2010 named "What Happened Before the Beginning?", where cyclic and ekpyrotic cosmological models are explained. In this episode the creators ...
4
votes
3answers
88 views

How long would it take to scan the visible universe for unique signals?

The article Amazing rays as star succumbs to dark side talks about a very large black hole swallowing up a star. The report goes on to say that the only reason it was discovered was because it shot ...
3
votes
1answer
258 views

Diameter of the universe [duplicate]

Should the diameter of our universe always be more than its age in light years? As if the distance between any two points in the universe is equal to 13.5 billion light years then the light from the ...
2
votes
1answer
118 views

What are we all falling towards?

One meteorite fell on the ground in Russia, last week. In different circumstances, it could have orbited the earth, or perhaps pass close to the earth and then disappear into the space. It seems that ...
2
votes
1answer
58 views

Observable universe does it account for farther away galaxies measure of the observable universe?

From our planet we can only see so far on any direction. If a galaxy farther out than ours had a planet would its view extend beyond our measurements?
1
vote
1answer
91 views

Looking backwards in time at yourself

If a person on Earth today is looking at a star, say, 10 billion light years away, is it possible that some of the atoms he is looking at will eventually go on to make him?
1
vote
2answers
63 views

Can we observe an edge of the universe? [duplicate]

Firstly, I apologise if my thinking is completely incorrect - I am by no means a physicist (yet!), I have included layman illustrations to hopefully assist in explaining my thinking. I am imagining ...
1
vote
1answer
170 views

How far away is Cosmic Background Radiation? [duplicate]

I've been reading about Cosmic Background Radiation (CMBR) lately. My understanding so far is that this is the "Noise"/"Flash" from the big bang. Assuming that information is correct, how far away ...
1
vote
1answer
21 views

What's the total Cosmic Microwave Background energy?

This is a part of my wider attempts at accounting matter in the observable universe. The total light ever emitted by stars and other space objects is capped around 1% of baryonic mass (in energy ...
1
vote
1answer
53 views

How many states are there in the observable universe

If we took a single instant and considered all possible states of all energy and matter do we have any bounds on how much that would be? Would that number be related to information?
1
vote
1answer
52 views

Size of the Universe: Curved vs flat? Finite vs infinite?

I have recently heard the theory that the Universe may be smaller than observed but may be curved to the extent that light rays may have looped past us once already and hence appear to have originated ...
1
vote
2answers
125 views

How is the observable universe mapped?

As I was looking at how big earth was relative to everything else in the universe, this picture boggles my mind. http://en.wikipedia.org/wiki/Observable_Universe#Horizons We're like the size of an ...
0
votes
1answer
697 views

Size of the Observable Universe [duplicate]

I wanted to know what the observable universe is so I was thinking and I thought, it must be age of the universe times 2. Well I was wrong. I found on one website that it is 46B LY across in each ...
0
votes
1answer
239 views

Large-Scale-Structure (LSS) and the Fingers-of-God

In the Large-Scale-Structure (LSS) artifacts named fingers-of-god are apparent in the redshift space and justified by "The large velocities that lead to this effect are associated with the ...
0
votes
0answers
67 views

How come that an Infinite universe will collapse under gravity?

In this PSE post the issue is about the stability of an infinite universe under Newtonian gravity. Here I'will drop the Newtonian constraint because we know of the finite speed of interactions and I ...
0
votes
1answer
73 views

How is it possible for you to be at the centre of the universe wherever you are? [duplicate]

I saw on Richard Hammond Builds A Universe on BBC2 a few days ago that you are always at the center of the universe wherever you are. Surely this is illogical, because you could never get to the edge ...