All Questions
Tagged with universe observable-universe
81
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2
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281
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Negative Horizon distance
Consider a flat universe, here, proper distance can be given by R-W Metric:
$$d_p (t_0) = c\int_{t_e}^{t_0}\frac{dt}{a(t)},$$ $t_e$ is the time when a photon is emitted from a distant galaxy, $t_0$ is ...
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64
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Horizon problem, what if our observable universe is roughly equal to the whole universe, especially in early times?
How do we know that at a time of 380.000 years, when CMB got free, the observable universe was not equal to the actual universe? Maybe they were roughly the same and couldn't that explain the horizon ...
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Does going to the other side of Milky Way galaxy mean seeing different observable universe?
What if there was a robot that got sent to the other side of the Milky Way by just traveling with a fusion engine and started orbiting a planet that has around Earth's gravity in order to avoid any ...
- 1,534
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Why can't we see past the observable universe?
Why can't we see light from beyond the observable universe?
I've done a lot of research on this and all I've found is unsatisfactory answers and straight up nonsense.
Some claim that the universe &...
- 131
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What is the rough distribution for number of galaxies with a given mass in the observable universe?
Is there a rough formula for the fraction of galaxies in the observable universe with masses between M and M + dM? Or perhaps a graph that displays the same information? I've looked online but can't ...
- 419
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Does expanding universe length units also expand? [duplicate]
Information
I have read an explanation about the expanding universe which represents our universe as a metal plate that tends to expand simultaneously in all directions while being heated. One can ...
- 73
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55
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Big Bang and where do we stand relative to it? [duplicate]
Maybe dumb question, not sure, but I would need some help here to understand.
https://theglobestalk.com/james-webb-telescope-see-back-in-time/
So according to physics we can look back in time ...
-4
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Cosmos at minimum 250x bigger than our observable Universe, so why then the need for a Big Bang?
Please correct me If I'm wrong but does not the BB only refers to our light speed limited observable Universe (OU) from our home position?
Also it is estimated that the Cosmos is minimum 250 times the ...
- 4,170
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Is the inflation rate of the universe uniform throughout?
Is inflation constant at any given moment throughout the entire observable universe? I realize inflation was once much more prevalent, so at the edge of the observable universe, we would observe a ...
- 213
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Distribution of matter in the Universe
My teacher explained today that quantum fluctuations in the early Universe (in particular, during inflation) determined the spatial distribution of small mass inhomogeneities, which, in turn, due to ...
- 956
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619
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How fast is the edge of the observable universe expanding from the Earth?
If the universe is expanding at 73 kilometers per second per megaparsec, what is the fastest expansion speed that we can observe from Earth? I'm assuming that's the edge of the observable universe ...
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9
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Is "speed relative to the universe" a well-defined concept? [duplicate]
Prompted by commenting on this question.
I offered the standard "Which frame of reference are you using? Yours? A satellite's? The sun's? The Milky Way's?" observation.
Which prompted me to ...
- 660
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4
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196
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Is it possible that the center of the universe is outside our observable universe?
Is it possible that the universe does have a center after all, but we just cannot see it because it already fell beyond the event horizon of our observable universe?
If not, how do we know this for ...
- 103
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How do galaxies cross our particle horizon?
At the begin of his lecture "The Quantum Origin of the Universe" (2014) James Hartle makes the following statement:
"A new galaxy with a 100 billion stars becomes visible - ie comes ...
- 928
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Are unreachable parts of the universe 100% unreachable or do we just say so?
In Kurzgesagt's video TRUE limits of Humanity is it stated that most of the universe will be forever unreachable because the universe is expanding faster than the speed of light. This is possible ...
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