Questions tagged [universe]

Questions regarding all of time and space and its contents.

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4
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2answers
184 views

What could be the utmost lowest temperature in the universe/multiverse?

What could be the utmost lowest temperature in the universe/multiverse?
2
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1answer
423 views

why are galaxies different in color?

whether its in movies,television,real-life or some planetarium different galaxies are shown in different color. For ex:- Milky way is always seen in Blue where as Andromeda gives out a bit reddish ...
2
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1answer
156 views

How can we use hypervelocity stars to determine the origins of the Universe?

I was reading this article finding evidence of Universe's origin, which describes that in 1 trillion years we may lose the ability to determine how the universe was created. The answer seems to be ...
3
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1answer
407 views

What suggests the cyclic nature of the universe? Proposed by Stephen Hawking

In "A Briefer History of Time" by Stephen Hawking he writes that if we were to travel faster than the universe were expanding and for long enough (in a straight line) we would eventually come back to ...
5
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2answers
395 views

Why are some universal entities round and others are flat?

I've been wondering for a while now why some objects in the universe (such as stars, planets, etc.) are round, while others are flat (galaxies, planetary rings and protoplanetary disks). I know these ...
16
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1answer
1k views

Explaining Dark Matter and Dark Energy to layman

With my little knowledge, I know this: Dark Matter The center of a galaxy controls/attracts its objects (stars, planets, comets etc.) towards itself because of gravity. But the mass of the center of ...
2
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2answers
250 views

Will the Universe end by time stopping?

I know there are several theories as to how the universe might end, if it does. Is it possible for it to end by time stopping? A friend of mine told me about this theory, but her explanation that it ...
1
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2answers
291 views

Is the universe moving through infinite space time as it expands?

What I mean by this, is imagine a person blowing up a balloon. As the balloon expands, the person blowing it up is also walking. At a much grander scale, apply this concept to the universe. As the ...
2
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1answer
312 views

Do some ELF (Extremely low frequency) radio waves pass the atmosphere

...reach Earth surface and then are reflected passing the atmosphere again to reach outer space? And once in outer space can they travel indefinetely in it or the interplabetary plasma would stop them?...
3
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2answers
132 views

Are there any sounds in space?

Is our universe noisy or silent? Can people hear them? When astronauts are out of the Earth and near an explosion, can they hear its noise.
2
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1answer
476 views

If the universe is 'flat', what shape is it? [duplicate]

As in the title, If the universe is considered to be 'flat', what shape is it? Is it a disc, elliptical, square, rectangle? Or is this still unknown as we can only study a small segment of the ...
8
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2answers
2k views

What is the physical, geometric shape of the universe?

I'm not asking about theoretical ball, vs saddle, vs flat surface which is just a metaphor with 2D space. It's hard to say as we see very little of it, and we see them in the past because light ...
1
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1answer
159 views

Why can we trust Hubble Time if the rate of expansion is not constant?

The age of the Universe can be estimated from taking the inverse of the Hubble constant: $t_\text{universe} = 1/H_0 =d/v.$ It seems to me this method assumes that any given galaxy has been receding ...
0
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1answer
83 views

Parts of the Universe Shows Fewer Named Stars [duplicate]

I'm becoming interested in the currently identified stars in the universe. There is a wide swath where much fewer named stars are shown. Why is this? The image below is a mollweide projection of the ...
8
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2answers
468 views

How does the concept of a universe with no center work?

I understand basically that the universe is homogenous (looks the same from every point) and I was told in my astro class that it's supposed to have no center, but how that works boggles my mind. I ...
0
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1answer
106 views

Can one calculate the size (i.e. the radius) of our universe? [closed]

If one can estimate the mass of our universe, might one also calculate its ultimate size, (after it fully expands), based on the Schwarzschild formula for the radius of a black hole? Please note that ...
6
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2answers
2k views

Relation between black hole mass and radius, and our universe's [duplicate]

Is there a graph of known black holes, with their estimated mass in the X axis and their estimated radius in the Y axis? If so, where can we find it? I would like to know if a black whole with the ...
1
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1answer
303 views

If the universe keeps expanding, can we travel to the edge of the universe? [duplicate]

If the universe keeps expanding, is it possible to travel to the edge of the universe?
3
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2answers
149 views

Is there any proof of space being created?

Is there any proof for space being created? Because I guess an explanation for the dark energy (dark = our understanding of it) could be that there is a gigantic amount of matter/dark matter that we ...
0
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1answer
510 views

Birthday of the Universe

With every improvement of measurement we are able to determine the age of the Universe more exactly. I just wondered how much and what means it would need to narrow the range of age so that it would ...
3
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1answer
202 views

How could we tell if the Universe is infinite? [duplicate]

I've heard from a number of people that the Universe is infinite, and from my perspective, I can't see how this can actually be known, especially given that the Universe started out a finite size and ...
0
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1answer
57 views

Locations of farthest matter

Regarding matter that has the highest redshifts, do we see such matter in every general direction we look (relative to Earth: up down left right front back)?
2
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1answer
212 views

Evidence of CMB redshift

Are there any known spectral lines shifted by ~1100? If not, then how certain is mainstream that the CMB has a redshift of ~1100? All I see is a blackbody radiation curve void of spectral lines.
2
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3answers
1k views

Are we center of universe? [duplicate]

So I just learned that CMB redshift is 1100 regardless where we look (up down left right). According to Hubble's Law that makes it around 46 billion light years away, making it the farthest matter ...
10
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2answers
1k views

Is the earth bombarded equally in all directions by neutrinos?

Perhaps it is hard to known for sure because neutrinos are very difficult to detect, although they do go through the earth in very large numbers. But are they passing through the earth equally from ...
0
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1answer
44 views

Are there events in universe which we receive first from their neutrino's instead of their photons?

Neutrino's are very small though they have mass. Because of that it is probably that the don't have a speed faster than photons. But is it in all events, like supernova's or else events, where it is ...
0
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1answer
2k views

What are the 10 most abundant elements in the universe by number of atomic nuclei?

I've seen websites that show the ratios of the 10 most common elements but they compare them by relative mass. I think it's more interesting to know the relative abundances of atomic nuclei because ...
-3
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2answers
867 views

What happens outside of the universe? [duplicate]

Since the universe is always expanding, that means there's an edge right? So what are some theories for outside of that growing edge.
0
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2answers
133 views

Regarding the age / size of the Universe [duplicate]

I believe the current estimated age of the Universe is around 14 billion years. I just read in another post on here that the diameter of the Universe is around 90 billion light years. This doesn't ...
-6
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1answer
129 views

Origin of the Universe [closed]

I heard on a you tube video that a new theory came out in 2015 . The theory is that there was no "Big Bang" and that the Universe has no beginning .
-1
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1answer
223 views

Is the flat curvature of the universe in the 5th dimension?

It is hard to imagine that the universe could have a flat curvature while I've read that it is at this moment the most likely. When you look around the universe is expanding in all directions, so it ...
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2answers
128 views

Why can't different regions of the universe be the same as they have the same origin?

The horizon problem states that because of the speed of information can't be faster than light and the distances between far regions are too big there is a problem because they look quite the same. ...
18
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1answer
11k views

How many sun-like stars are there in the universe?

After yesterday's announcement of the Kepler telescope finding a huge amount of newly observed exoplanets, i saw a headline claiming that as much as 22% of sun like stars in the universe have planets ...
5
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1answer
624 views

Why when we look through a telescope in space, do the billions of stars not block our view from seeing further?

I know that we are able to "see back into time" by looking very far away through telescopes such as the Hubble telescope, but my question is, wouldn't you run into at least a couple of stars that were ...
2
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3answers
344 views

Meaningful theories of the shape of the universe

Normally, when people say "the universe is infinite" they generally mean something like "the observable universe is locally flat, it is easy to assume that it is flat way beyond the observable ...
5
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1answer
328 views

What is driving the expansion of the Universe?

Is it just the momentum from the Big Bang? If yes, how can it account for the acceleration of the expansion? Why isn't the collective gravitational force slowing it down? What part does dark energy ...
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2answers
158 views

Is parallel universe possible [duplicate]

Does parallel universe really exists or just science fiction which ain't possible? Can we ever know ?
-3
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2answers
102 views

Large hadron collider [closed]

Whether the collision of particle will lead to a massive WORMHOLE or if BLACKHOLE is also possible? How much I know is that it's created for einstien's E=mc^2 ,conservation of energy from mass and ...
-10
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1answer
448 views

Is this Universe scenario correct? [closed]

I will try to give you my reasoning behind my scenario. Ok I've researched and found That 95 percent of the galaxy has been formed already, And the other 5 percent is still to come.http://www....
2
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1answer
244 views

How do we know the current state of the universe by observing it from Earth?

Since light travels at the constant speed and takes more than a billion years to travel from the distant parts of the Universe, how do we know the state of the distant regions? Do those still exist or ...
3
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1answer
229 views

What was “space” like before big bang?

I have a simple question which I think about often but have no answer. If The Big Bang is true, than if the whole space was just a point 14 billion years ago, then what was around that point, some ...
11
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3answers
870 views

How does light affect the universe?

When light is emitted by for example a star, that star loses energy - which causes it to reduce its gravity. Then that energy begins a journey for potentially billions of years, until it reaches some ...
8
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4answers
748 views

Why does it make sense to say the universe has no centre?

If we suppose we and everything in the universe is perfectly flat. That is, we have width and depth, but no height. And we are situated on the surface of a balloon blowing up with air and expanding "...
1
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1answer
232 views

Second Big Bang [duplicate]

Just say you are immortal and will live forever. Since the universe is claimed to be unstable, what would happen after it ends? Would all of the universe's mass just fly back into another compressed ...
2
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4answers
202 views

If I were to point into the sky, how many galaxies would be in this line?

If I point in the sky and draw a line from the tip of my finger to the end of the universe, how many galaxies would this line cross? I had a discussion with my dad and he said due to the universe ...
1
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1answer
278 views

How do we know that the Universe is still expanding now?

Yes, I know that most galaxies have a red shift and that means they are moving away from us. The problem is that the farthest galaxies are 13.8 billion light years away. That means that the info is ...
2
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1answer
314 views

Does gravity bend light, and how much time does it take for light to cross gravity of a Black Hole?

This is very confusing to me, so the question might be same. Please go through it, if required i will add more text. According to Einstein's theory of general relativity, photons are not technically ...
3
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1answer
82 views

Formation of our Universe

So I got this information from a magazine , Scientific American issue Physics at the Limits. The theory is that our Universe came about, when in the "Bulk Universe", which is four dimensional, a four ...
2
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1answer
80 views

What does an Einstein-De Sitter universe look like?

I know an Einstein-De Sitter universe is a "flat" universe, i.e. with a K ("bendiness", sorry, don't really know what to call it in English) factor of 0, but does that entail anything as to its ...
3
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2answers
456 views

Is time itself speeding up universally?

Time moves more slowly near a mass than in relatively empty space. For example, I get that an observer would see someone falling into a black hole to appear to move more slowly and get "stuck" on the ...