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Questions tagged [universe]

Questions regarding all of time and space and its contents.

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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 ...
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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 ...
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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 ...
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3answers
2k views

Are black holes expanding?

We know that it is a commonly heard claim that in every black hole there is a universe. It is also believed that the universe is expanding. If we use both of these, can we conclude that every black ...
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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 "...
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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 ...
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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 ...
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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 ...
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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 ...
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1answer
781 views

If the Universe is infinite, would heat death be impossible?

If the Universe is infinite, one would imagine that if we kept moving through space, we'd constantly find newer and newer galaxies and objects forever. This would imply that there is an infinite ...
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2answers
741 views

Are objects in the universe moving away from each other at the same acceleration?

This is a follow up question to Does the universe expand at the same rate everywhere in the universe?. If the universe is expanding, then it would seem necessary for each object (ie galaxy) to be ...
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3answers
5k views

Does time slow down because the universe is expanding at an accelerating rate?

If the universe is expanding at an accelerating rate, such that the galaxies' moving away from each other is accelerated, then time should also slow down. And when universe will accelerate to the ...
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1answer
209 views

Where are we in an approximate timeline of the possibly habitable universe?

Our universe is supposedly 13+ billion years old and our Sun is a third generation star. It seems to me that we are now in a relatively young stage of the universe. How many generations of stars will ...
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1answer
193 views

A universal reference point [duplicate]

I would like to use a system of co-ordinates (x,y,z,t) based on a specific well known point. My original choice (the center of the universe in the big bang theory, Bigbang0), was wrong as the universe ...
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3answers
211 views

Why can't this be the simple (and obvious) explanation for the dimming of KIC 8462852?

Couldn't it be just a relatively large object, anywhere in the interstellar space between the star and Earth? I mean, look out the window at a far away car or a tree, then stretch out your hand and ...
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1answer
160 views

Is there any other theory, apart from the Big Bang paradigm, which describes the birth of universe? [closed]

The Big Bang theory is the approved theory of the "birth" of Universe. Are there any other theories which can explain how our Universe came into existence?
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2answers
220 views

Is ours the first universe?

I see here that after a very long time into the future, "Estimated time for random quantum fluctuations to generate a new Big Bang". This begs the question, do we speculate that our big bang was the ...
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1answer
257 views

Is our Universe a hologram? [closed]

I watched a documentary where I heard some very strange theories that are difficult for me to comprehend. It is even difficult for me to explain what I heard. "Objects that fall into a black hole ...
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2answers
186 views

Could we estimate the age of the universe based on the planar property of the Solar System?

The Big Bang scattered planets and stars everywhere in three dimensions. But after billion years of moving and interacting with each others through gravity, planets moved on the same plane. Given ...
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3answers
160 views

infinite Universe [duplicate]

I was watching a documentary and they said that Cosmologists have determined that the Universe is infinite. I find this to contradict the expansion theory. If the Universe had a starting point then ...
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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 ...
3
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2answers
147 views

The universe is dying vs the universe is ever expanding

How does the idea that the universe is dying (trumpeted as some big new revelation the past few days on several new sites I keep seeing pop up on google news) square with the idea that the universe is ...
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1answer
66 views

Which structure is represented in this video (if any)?

I know this is not supposed to be precise since it is just a movie but I would suppose it is based on real things. In the Contact movie intro https://youtu.be/EWwhQB3TKXA?t=1m I think the Milk Way is ...
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3answers
2k views

What does Stephen Hawking mean by 'an infinite universe'?

In the recent $100m search for extra terrestrial life project project, Stephen Hawking is quoted in the following way: "We believe that life arose spontaneously on Earth," Hawking said at Monday's ...
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2answers
341 views

Is the diameter of the observable universe a relative quantity?

The diameter of my observable universe is 90 billion ly measured in proper distance. But isn't lenght a relative quantity in the theory of Relativity? Could an observer moving at a different velocity ...
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1answer
314 views

Age of the universe vs. its contents

A couple of decades ago I read an article (could have been either Astronomy, Space, or Science News) that suggested the contents of the universe may be older than the universe itself. Of course, that ...
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1answer
131 views

Accelerating universe expansion and standard candle

Recent stars (and standard candle supernova), afaik, contain more heavy elements than older stars. As consequence, I guess, recent stars and supernova should be slightly dimmer than older stars? If ...
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2answers
818 views

Is our universe included inside a black hole?

This question repetitively comes to my mind but I've never found any good scientist article to argue about it, only esoteric or speculative web articles without much valuable background. So let's ...
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2answers
193 views

Is mass+energy conserved when a new universe forms inside a black hole?

My understanding is that there are credible theories out there in which the formation of a singularity in a black hole also represents the beginning of a new universe via a big bang. We can't see the ...
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2answers
441 views

Calculating the age of the universe

Is the calculated age of the universe that of the visible universe or the entire universe? I dont know how the age is calculated but if it is believed that all we see visibly IS the entire universe ...
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3answers
2k views

When the universe expands does it create new space, matter, or something else?

I am wondering what exactly is meant when it is said the universe expands. Does it simply create new space for matter to fill, does it also create new matter/dark matter to fill that space, or am I ...
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4answers
2k views

Does the mass of the observable universe ever change?

First do we have anyway to even estimate the mass of the entire observable universe? And then is there any data that shows mass being gained or lost? Would we ever know if someone was playing with ...
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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?
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2answers
98 views

Is the Oort Cloud actually opaque, or is the “cloud” used euphemistically because minor planets inside of it are too dim to be seen?

I did read several of the Oort Cloud questions/answers which I found very helpful and instructive, but this question still persists for me: Is the Oort Cloud actually opaque, or is the "cloud" used ...
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9answers
2k views

Is there any practical use for astronomy?

Although astronomy is very cool and the things we are learning are awesome, is there really any practical use to knowing the things we know about the universe? Do other fields of science draw from ...
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3answers
463 views

BIG CRUNCH Theory

Someday before i read about a article which explained about a phenomenon called BIG CRUNCH, according to it the way Big Bang happened because of which the remains moved away from one another forming ...
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1answer
579 views

Was the cosmic microwave background (CMB) radiation originally gamma rays?

I believe that sometime after Big Bang the entire universe was filled with high energy particles. Now we fast forward to the present; most of these particles still linger and managed to avoid being ...
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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 ...
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2answers
118 views

Is dark energy evenly spaced throughout Universe?

Are there certain parts of the Universe that are expanding faster than others? Is there anyway to definitively measure this?
4
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1answer
257 views

Are galaxies moving away from us faster than before?

Are all galaxies moving away from us at constant speed even those that may be moving in our direction as the space is being formed? How does nothingness appear to push matter? A black hole sucks as ...
3
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1answer
148 views

visualisation of the universe's expansion

in physics we were learning about the universe and the big bang. we were being told that everything came from one point and 'exploded' outwards, and is continuing to expand. I felt that this ...
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1answer
185 views

What is the acceleration of the stars' speed in the Universe? Positive or negative? [closed]

I have read quite different opinions about that, so can someone tell me what is the sign of the acceleration of the stars in the Universe if we accept that the center of the Universe is the beginning ...
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2answers
195 views

The destruction of the Universe by a bubble

So I was watching a documentary on television about this and a number of theories that are proposed as to what the fate of the Universe will be: "Big Crunch" "Big Freeze" "Big Rip" I understand ...
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2answers
4k views

How can I see a nebula?

I've recently been seeing a bunch of pictures of nebulae and I'm just fascinated by their beauty and complexity. Is there any kind of telescope that would make it possible to view it from here on ...
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2answers
212 views

Is the universe simply a mass of atoms in 'void'; what does it look like?

I've always been stumped with the question of what lies beyond the universe, and I've come to the firm conclusion - void (i.e. completely empty). Does it make sense then to think of the universe as a ...
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1answer
110 views

Origin of the original bright light and matter [closed]

Do any theories exist as to where this bright light and matter came from that expanded to form our Universe ?
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1answer
842 views

Big Bang / Big Crunch cycle?

I've been reading some of Stephen Hawking's work on the theory of the expansion (and ultimate contraction) of the universe and was curious if anyone has every hypothesized that the universe has ...
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1answer
237 views

Universe as 2d sphere surface - a round trip?

If Universe's analogy is 2D surface of the sphere, could we come around in circle? Say on Earth you decided to travel straight in one direction, after completing one full circle you'd find yourself at ...
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1answer
401 views

Solar System formation, considering its and the universe's age

It is known that the Sun is 4.6 billion years old, and the complete Solar System is of a similar age. The class of stars to which the Sun belongs seems to be quite common. Stars of its class can live ...
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1answer
209 views

What it would look like to observe people with a different time flows?

As I learned, that the bigger gravity source you are influenced by the more slow time ticks for you, the farther away you are from a gravity source the faster times ticks. So Imagine two different ...