Questions tagged [observable-universe]
Questions regarding the region of space containing all the objects that we can detect using any method of observation.
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Are there any galaxies which fell out of sight horizon due to cosmic expansion?
If farthest galaxies run away from us with acceleration making them exceed speed of light, we should expect them to disappear from sky among time with increasing quantity. Did we observe this? Can we ...
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How can the universe be expanding faster than speed of light? [duplicate]
So the story goes like this:
A long time ago, 13.799±0.021 billion years to be exact, something happened. It was a big bang, loud explosion and universe came to existence. It grew and grew, and now ...
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Is it "nonsense to even talk about" objects outside the observable universe not having gravitational influence on us? (finite speed of gravity)
In this supplemental answer to Is the zero gravity experienced in ISS the “artificial” kind? in Space Exploration SE I said:
Gravity moves at the speed of light so nothing outside out observable ...
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Does the recent news of "ten times more galaxies" imply that there is correspondingly less dark matter?
Nature: Universe has ten times more galaxies than researchers thought
NASA feature: Hubble Reveals Observable Universe Contains 10 Times More Galaxies Than Previously Thought
Headlines sometimes ...
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Why are all quasars so far away?
Why are all quasars so far away?
If the universe is homogeneous, we should expect to have a homogeneous distribution of quasars, but all of then seem to be far away from Earth. Why is that?
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How much of the Universe is invisible to us, and how does it affect our theories?
I watched an interview with Neil deGrasse Tyson on The Late Show with Stephen Colbert where he briefly mentioned a disturbing thought. It is something that I have never thought of before, and the idea ...
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Can we see the Big Bang happen if we look far enough?
The observable universe is constantly expanding as more light from the Big Bang reaches us. This light has been travelling for billions of years, so we are looking at the universe as it was a few ...
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Why can we observe the Cosmic Microwave Background no matter the direction we look?
I often read that the CMB was released from everywhere in the Universe, in every direction.
If that statement is true, can someone elaborate what "everywhere in the universe, in every direction" ...
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Does the CMB pattern evolve in a human lifetime?
I was thinking, as CMB is a snapshot of a slice of the Universe during recombination, how much the cmb is changing with time ?
I mean as we progress in time we look a CMB a bit more faraway each time, ...
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If we watched extremely red-shifted galaxies near the edge of the observable universe for a very long time, how would they change? Would more appear?
I have understanding sphere eversion as #1 on my bucket list (if I ever get a round tuit) but understanding metric expansion seems to be a rapidly receding possibility :-)
Question: Suppose it takes ...
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How many new galaxies enter the observable universe each day/year/decade?
Each day light has more time to reach our eyes from distant galaxies. In one day, light travels 2.59×10^10 km.
So our observable universe (assuming my simple math skills apply here and there isn't ...
crclayton
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How long would it take to reach the edge of the reachable universe?
How long would it take to reach the current edge of the reachable portion of the universe, with the following bounds in mind:
We figure out a way build a space ship to provide a constant 1 G ...
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What is the hottest thing in the universe?
Straight from my 7 year old to you, exactly what it says on the cover:
What is the hottest thing in the universe?
To make it Stack Exchange-friendly, I'll add the following caveats:
it should be ...
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Why can't we see distant galaxies with the naked eye?
If light keeps travelling in a straight line, why can't we see distant galaxies with the naked eye? Surely if you stared long enough, the light from them would eventually hit your eye? I apologize if ...
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Approximately what percent of the sky has nothing in it?
From my persepective here on Earth, the sky seems to look like a few large-ish things and a bunch of tiny things. Hubble teaches us that even the apparent void between the tiny things has many very ...
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