Linked Questions

54
votes
7answers
9k views

Why is the observable universe so big?

The observable universe is approximately 13.7 billion years old. But yet it is 80 billion light years across. Isn't this a contradiction?
12
votes
3answers
522 views

How can the diameter of the universe be so big, if nothing can go faster than light? [duplicate]

The following are facts of the prevailing cosmological model. The age of the universe is about 13.772 billion years. Nothing with mass can exceed the speed of light. The diameter of the observable ...
3
votes
1answer
4k 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 ...
5
votes
1answer
681 views

Speed of light and current dimensions of the universe [duplicate]

I've seen several documentaries explaining that the diameter of the universe is currently estimated at over 90 billion light-years. And which that - in the face of the age of the universe being about ...
2
votes
2answers
91 views

How is observable universe so big if the universe is so young? [duplicate]

The diameter of observable universe is 93 billion light years but the age of universe is only estimated to be 14 billion years. So how does light have 46.5 billion years to travel from the boundary of ...
2
votes
0answers
93 views

Why is the radius of the universe larger than? [duplicate]

It's always been in the back of my head that the Universe is 13.8~ billion years old and that the Observable Universe is 46~ billion light years in radius. How is this so? It would logically be only ...
152
votes
12answers
23k views

Why does space expansion not expand matter?

I have looked at other questions on this site (e.g. "why does space expansion affect matter") but can't find the answer I am looking for. So here is my question: One often hears talk of space ...
28
votes
1answer
3k views

Why haven't we seen the big bang?

The Andromeda galaxy is 2,538,000 light years away, so if we view Andromeda from a telescope, we see Andromeda how it was 2,538,000 years ago. Now the diameter of the visible universe is 92 billion ...
12
votes
5answers
3k views

How is it possible for astronomers to see something 13B light years away?

In a NPR News story from a few years back: "A gamma-ray burst from about 13 billion light years away has become the most distant object in the known universe." I'm a layman when it comes to ...
5
votes
2answers
974 views

Can the distance of a quasar be determined accurately?

As noted in How can a quasar be 29 billion light-years away from Earth if Big Bang happened only 13.8 billion years ago?, the wiki about quasars still contains the following misleading sentence: "...
3
votes
4answers
2k views

How far has a 13.7 billion year old photon travelled

I've read that the size of the observable Universe is thought to be around ~46 billion light years, and that the light we see from the most distant galaxies were emitted ~13.7 billion years ago as a ...
4
votes
2answers
1k views

Galaxies moving away at the speed of light

As an arts student, I really find those cosmological questions hard to understand and hence come here to seek your kind help. The Hubble constant $H_0$ is estimated to be about 65 km/s/Mpc, where 1 ...
3
votes
2answers
601 views

How does gravitation propagate along curved spacetime?

In this wikipedia article it is described how a beam of light, with its locally constant speed, can travel "faster than light". That is to say it travels a distance, which, from a special relativistic ...
-4
votes
1answer
153 views

Infinite Space && Infinite Energy? [closed]

If space is infinite, it's it also possible that energy is infinite? Given that we can't really conceptualize infinite space, could we say with certainty that energy is not infinite? How?
1
vote
3answers
138 views

Can gravity transfer to the other side of the universe?

Since the speed of gravitational wave is limited by the speed of light, and a light can never transfer to the other side of the universe because it is expanding so fast. So does that means gravity ...

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