All Questions
32
questions
2
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0
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58
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The gravitational field of all the distant mass exactly cancels the positive mass-energy in the universe. Why do they think so? [duplicate]
It is often said that the gravitational field has negative energy, and that this negative gravitational energy of all the distant mass exactly cancels the positive mass-energy in the universe.
Why do ...
- 278
0
votes
2
answers
488
views
Is most of the energy in the universe potential energy?
So I asked a question about what would happen in regards to gravitational potential if I left earth and then vaporized it. The answer I got was that the Mass would still remain the same and even if ...
2
votes
3
answers
458
views
Can you explain this line from "A brief history of time"?
Newton realized that, according to his theory of gravity the stars should attract each other, so it seemed they could not remain essentially motionless. Would they not all fall together at some point? ...
- 39
2
votes
1
answer
105
views
How can we be sure that gravity is not the reason for the perceived expansion of the universe? [closed]
The question has been partially discussed here but I believe the following formulation is a bit different.
What experience could disprove the notion that the universe is not expanding despite the pull ...
- 145
0
votes
1
answer
109
views
How does space change as the universe expands?
Consider a metre ruler. Despite the universe – and space itself – constantly expanding, the ruler maintains its size. If this ruler was alone in empty-ish space, other distant objects would appear to ...
2
votes
1
answer
281
views
How does universe expand when cosmological constant is zero?
From what I learned, Einstein believed in a static universe but from his general relativity equations universe must collapse under gravity. Hence Einstein adjusted this gravity with cosmological ...
- 126
0
votes
1
answer
104
views
Are there other theories than gravitational attraction taken into account as a reason for the extreme accumulation of matter in the universe?
This question is about how small the interstellar density is (less than 1 atom per cubic centimeter).
But although the interstellar density is very low, matter tends to extremely aggregate in certain ...
- 282
1
vote
0
answers
30
views
Is it possible that the acceleration of the growth of our universe is driven by the overall gravitational pull of neighboring universes [closed]
I am painfully unequipped when I think about my my knowledge of physics. Still, I am enthralled, as many of us are, by the mysteries and complexity of the universe, both known and unknown.
I was ...
- 29
1
vote
1
answer
578
views
Zero-energy universe - What is nothing?
I am a layman, so excuse me in advance for the stupidity of my questions, and I hope you can answer them in a way that I can understand.
I have read, here and there, that the Universe might have a ...
1
vote
1
answer
888
views
Why is the heat death, rather than a Big Crunch, the most accepted theory of the ultimate fate of the Universe?
The Heat Death is accepted by most as the end of the Universe, but how can that be? Wouldn't the Big Crunch make a lot more sense? I mean, even if everything in the Universe is spread out uniformly ...
- 41
0
votes
1
answer
101
views
Is this how vacuum works?
Vacuum exerts a net zero force, or i guess pressure? on what's inside it, right? So if the universe is expanding at an accelerating rate, is the vacuum of outer space is growing? Like space is ...
0
votes
2
answers
396
views
What is the definition of gravitational horizon $R_h$ in the $R_h=ct $ universe?
Melia's $R_h=ct $ universe proposal suggests that our gravitational horizon $R_h(t)$ should be equal to $ct$ for all cosmic time $t$, not just its present value $t_0$:
"several unpalatable ...
- 4,452
0
votes
2
answers
858
views
Will everything eventually be a single black hole? [duplicate]
Given the idea that gravity is always a factor (even though greater distances are excessively tiny), would everything eventually end up forming a single black hole?
My thinking is that, with infinite ...
- 1,083
2
votes
1
answer
510
views
Why doesn't the universe collapse under its own gravity?
Is the reason the universe doesn't collapse into itself due to gravity because there is an infinite amount of bodies in infinite space, therefore there is an infinite amount of gravitational pull on ...
- 21
-4
votes
1
answer
104
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Are far objects really accelerating away at that huge rate? [duplicate]
Discutssions around this question
Why is light bent but not accelerated?
got me thinking. Specifically, hsinghal said
"The absorption lines appeared to be red shifted (de accelerated photons) they ...
- 56