Questions tagged [universe]
Questions regarding all of time and space and its contents.
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How can we predict a Big Crunch when all galaxies are moving further apart?
I've read that the further away a Galaxy is from us the faster it moves away.
By this logic how can scientists predict that there will eventually be a big crunch when every piece of matter is ...
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Is the universe expanding faster than speed of light?
The celestial bodies like stars and galaxies are moving away from each other. How fast are they moving apart? Is that speed more than the speed of light?
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Is it possible to be 'still' in space?
So I was reading this answer about how galaxies are the fastest moving objects in the universe because space is expanding faster than the speed of light. This got me wondering, would it be possible to ...
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The reason behind Big Bang
It always amuse us to research about things around us and we always start our research with a question that - what must be the reason for happening of that phenomenon?
As we know that the formation ...
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Is it possible to create an artificial Black Hole?
I am quite curious about black holes. Once I just thought whether it is possible to create an artificial Black Hole, i.e. an human made black hole. Also explain there formation if it is possible.
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What is the speed of light relative to (in space)?
From what I understand the universe is expanding faster than the speed of light and accelerating so that it's possible that a given galaxy: $A$ will no longer be visible to another given galaxy: $B$.
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Age of the universe
A Galactic year is estimated to be around 250 million "terrestrial" years. That means there will be about 4 rotations per billion years. And age of the universe is estimated to be near 13.8 billion "...
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If we lived in a multiverse, what would our universe most likely then be named? [closed]
We live in the Milky Way Galaxy, but we don't just call it "The Galaxy", because we know there are multiple different galaxies. So if we lived in a multiverse, it wouldn't make much sense to ...
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What is that void that the universe is growing into? [duplicate]
We understand that this is the universe and it is essentially full of space and time, but what is on the outside of the universe, and isn't that nothing, something, and how far does that reach.
I.e. ...
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Can we only see the past of the universe? [duplicate]
So I was reading some interesting stuff about universe and Big Bang and wanted to make sure one thing. As far as I understand everything we can see about universe is the past, right?
I mean all the ...
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What would we find if we could travel 786 trillion light years in any direction
I've sometimes heard of galaxies that are millions or billions of light years away but if we could instantly travel 786 trillion light years in any direction, what are we likely to find? And what if ...
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Can we know whether any distant galaxy is moving away in same direction or in opposite direction w.r.t. our galaxy?
The Hubble law states that the recessional velocity of a galaxy is proportional to its distance from us.
It takes redshift and angular sizes (for distance) of the galaxy to determine velocity, and ...
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Can there be a 2nd possibility deduced from the fact that galaxies are moving away from us?
I just read that according to the BBT the universe is expanding. This is evident from the fact that distant stars (and galaxies) are moving away from us. But it could also happen that the universe is ...
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Why are distant galaxies not visible in the observable Universe?
Assuming that the Universe is and has been expanding ever since its creation (Big Bang theory), the galaxies that are now at the 'edge' (not visible theoretically) must have been (at some point in ...
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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 ...
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Contradict the expansion of the universe?
Lets say that we observe in a distant galaxy cluster, which in all the galaxies move far away from us.
and here we see in the same cluster a galaxy that move away from us in a much lower velocity ...
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How far are we from the edge of the Universe? [duplicate]
Following the Big Bang the Universe continues to expand, presumably and roughly equally in all directions. It is understood that the Big Bang occurred 13.798 ± 0.037 billion years ago.
Is there any ...
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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 ...
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Where is all the antimatter?
The universe supposedly started off with equal parts matter and antimatter and they are said to annihilate each other. Also, nature is famous for it's balance between everything. So all we see is ...
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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 ...
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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 ...
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Are there any alternative explanations for the gravitational force we attribute to dark matter?
It always seemed counter-intuitive to me that we observed an measured a gravitational force and since the universe has not enough mass to account for it, the conclusion was to say there's a different ...
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Has life been discovered outside of Earth?
I've just watched a movie that made me curious as to whether life has really been discovered on another world such as Europa??
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How are Galaxy Super Clusters Generated
I have seen pictures of clusters of galaxies, usually used in regards to theories of dark matter and galaxy formations. One of the most famous ones has the perceived shape of a stick-figure. If I am ...
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Why is the observable Universe larger than its age would suggest?
The age of the Universe is estimated at 13.8 billion years, and current theory states nothing can exceed the speed of light, which can lead to the incorrect conclusion that the universe can't have a ...
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Does our universe have to be embedded in a higher dimensional space?
I've heard that our universe may be open or closed. If it's closed it might have a toroid shape. If this is the case, would that imply that our 3 spatial dimensions have to be embedded in a higher ...
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What's the largest non-spherical astronomical object in the universe?
Some asteroids and comets are non-spherical. But is the nature of big things and gravity so that large things in the universe are always spherical? What is the biggest astronomical object in terms of ...
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What's the fastest moving object in the universe?
We know that nothing can have proper velocities larger than the speed of light in vacuum. But are there any objects in space that get close to it? Any comets, or other objects thrown by gravity or ...
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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 ...
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Is there a natural process by which hydrogen is generated from heavier elements in the cosmos?
we know that stars fuse hydrogen into helium starting at 3 MK; 13 MK in the Sun's core;
carbon fusion starts at above 500 million K, and silicon fusion starts at over 2700 million K for comparison;
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What do shape of universe mean? [closed]
What shape does a three dimensional universe have ? and how did scientists determined that it is flat and not curved.
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What is in the center of the universe?
If the universe has formed & originated by a Big Bang Explosion, then there must be empty space left in the center of the explosion site, as all the matter is travelling at tremendous speeds away ...
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How exactly is our universe mapped?
Watching this youtube video shows that our planet is nothing more than dust in the wind.
At the 2:50 mark in the video, you will see a view of the whole Milky Way. At the bottom you will see this ...
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Do parallel universes exist?
Do other universes like ours exist?
If they exist, how do we know that they exist when we have even not seen the ends of our own universe?
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On what scale does the universe expand?
According to the theory (or my understanding of it), the universe is not only expanding, but speeding up.
If the galaxies are moving apart, are the solar systems within them also moving apart from ...
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Can any information leave a black hole?
Referring to this question, is there any information that can leave black holes? Are they causing a permanent information loss in our Universe?
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