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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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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How do scientists know that the distant parts of the universe obey the physical laws exactly as we observe around us?
How do scientists know that distant parts of the universe obey the physical laws exactly as we observe around us?
The question might look a bit odd but I am really stuck on my head. We know, ...
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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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How much larger will the "observable by us" universe be when JWST becomes operational?
Right now, using all our various current means of observing, we can "see" a sphere of X diameter around us. Webb will increase that to Y diameter. So our observable volume will increase by ...
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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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How can telescopes see anything at all?
I'm impressed that we have any telescope imagery at all. Take the images we have from the "Pillars of Creation".
The Pillars of Creation is in the Eagle Nebula, some 7,000 light-years away ...
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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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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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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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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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As of now how much larger is our practically observable universe compared to just prior to JWST becoming operational
On April 2 2022 I asked for estimates of expected results. How much larger will the "observable by us" universe be when JWST becomes operational?.
As of Jan 27 2024 with JWST operational for ...
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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 CIBER Experiment from Caltech suggest that there can be lots of stars which are not in any galaxy?
My question is about the implications of the observations recently made by the Cosmic Infrared Background Experiment, or CIBER, from Caltech. I've read at Caltech web site:
"The total light ...
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How many individual extrasolar "shiny" objects has humanity identified?
Sorry, if this is a 'stupid' question of a non-expert, but this question came recently up in family discussion of mine and I couldn't give a satisfactory answer:
I know we have good (?) estimates of ...
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Is there anything currently 46 billion light years away from Earth that we can see?
If the oldest galaxy ever discovered, i.e GLASS-z13, is at a present proper distance of around 33 billion ly from Earth, why then do we define the observable universe to have a radius of around 46 ...
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