The space-expansion tag has no wiki summary.
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Is there anything physically infinite?
I can't think of a single thing that could be infinite.
Because the universe is expanding, isn't it? But there is an ever-changing barrier, so why could there be anything infinite, both ...
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2answers
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Is it possible that universe might not be speeding up expansion?
I'm not sure but I was thinking of galaxies shrinking with time while still moving apart from each other at almost a constant speed or less (i.e: uniform/slightly decelerating expansion). This may ...
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Can space expand with unlimited speed?
At the beginning, right after the Big Bang, the universe was the size of a coin. One millionth of a second after the universe was the size of the Solar System (acording to ...
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4answers
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Redshifting of Light and the expansion of the universe
So I have learned in class that light can get red-shifted as it travels through space. As I understand it, space itself expands and stretches out the wavelength of the light. This results in the light ...
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If everything in existence were increasing in size at some rate, would we be able to detect it?
Would our eyes observe any changes?
What about electronic measurement devices?
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Does the amount of gravitational potential energy in the universe increase as it expands?
It seems to me that extra gravitational potential energy is created as the universe expands and the distance between massive objects such as galaxy clusters increases; this implies that energy is not ...
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Could some Red and Blue shifts be the result of light passing through “dark matter”?
As i see it, light behaves in certain ways, as the Double Slit experiement shows,
So when light comes into contact with dark matter, it becomes both a wave and a particle, the wave is bent around the ...
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1answer
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Could entropy explain dark energy?
This was 3rd beer idea, so please bear with me. What if the universe was not actually expanding but the speed of light was slowing? Wouldn't that be indistinguishable to our observations? Either way ...
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How do we measure the range of distant objects despite relativistic effects?
When we observe astronomical objects like distant galaxies there are several complicating factors for estimating the distance:
Relativistic speed result in length contraction
Relativistic speed ...
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1answer
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Could the outer structure of the Universe be made from Antimatter?
Cern recently stated that antimatter may be repelled by matter, much like the opposite effect of Gravity. So is it possible that antimatter is actually repelled to the edges of the Universe to create ...
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Acceleration in the rate of expanansion of the universe due to weakening gravity?
Could the acceleration in the rate of expansion of the universe be due to the weakening of gravitational forces, as the distance between objects continues to increase?
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1answer
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Is dark matter expanding the universe, and creating the structures within it?
If dark matter repelled other dark matter, as well as regular matter(atomic or celestial), and regular matter were repelled by other regular matter "less" than by the dark matter, would not this ...
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Cosmological redshift interpretation
Can the cosmological redshift be interpreted as atomic frequencies increasing by the scale factor as the Universe expands?
This explanation seems closer to the truth than the popular idea that a ...
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When spacetime expands to the point where galaxy clusters are not observable, will there by any interaction?
It's my understanding that in a few billion years, clusters of galaxies won't be able to directly observe one another due to the expansion of spacetime overcoming gravity between those clusters. ...
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1answer
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Why don't orbits expand with the Universe?
Consider two bodies orbiting each other.
As the Universe expands would the distance between them increase?
Most people say that a gravitationally bound system will not expand with the Universe. They ...
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3answers
2k views
Why is the universe so big?
The Universe is approximately 13.7 billion years old. But yet it is 80 billion light years across. Isn't this a contradiction?
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2answers
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About hubble observatory and distant galaxies [duplicate]
According to Hubble observatory, the age of universe is 14 billion years. But, the distant galaxies are about 40 billion light years. How could that simply be possible? That means the information that ...
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2answers
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Why cosmic background radiation is not ether?
why cosmic background radiation is not ether? I mean it's everywhere and it' a radiation then we can measure Doppler effect by moving with a velocity.
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What experiments, other than Hubble Expansion, support the Dark Energy theory?
Dark energy is introduced as a constant inside Einstein's equations. Its primary purpose, from what I understand, is to make Einstein's equations compatible with the accelerating expansion of the ...
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How can a quasar be 29 billion light-years away from Earth if Big Bang happened only 13.8 billion years ago?
I was reading through the Wikipedia article on Quasars and came across the fact that the most distant Quasar is 29 Billion Light years. This is what the article exactly says
The highest redshift ...
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1answer
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Galaxies moving away at the speed of light
As an arts student, I really find those cosmological questions hard to understand and hence come here to seek your kind help.
The Hubble constant $H_0$ is estimated to be about 65 km/s/Mpc, where 1 ...
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3answers
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How long does it take for expanding space to double in size
I have been reading about Hubble's constant and trying to make 'sense' of the theory of the expanding Universe. Is is possible that space in the universe expands uniformly? If so, absent of other ...
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3answers
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Looking out into the universe means looking back in time - how does that work?
This is a question that has been gnawing on me for many years now. Back a long time ago, as I recall in reference to a scene in a popular science show on TV, I was asked the following.
The claim is ...
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3answers
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Seeing cosmic activity now, really means it happens millions/billions of years ago?
A Recent report about a cosmic burst 3.8 billion light years away. It is written as though it is happening now. However, my question is, if the event is 3.8 billion light years away, doesn't that mean ...
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2answers
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Universe Expansion and two tennis balls
Clear the universe of all matter except for two tennis balls. Place the two tennis balls in the same inertial frame 1 Mpc apart.
Are the tennis balls getting further apart?
Will the tennis balls ...
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1answer
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Size of the Observable Universe [duplicate]
I wanted to know what the observable universe is so I was thinking and I thought, it must be age of the universe times 2.
Well I was wrong. I found on one website that it is 46B LY across in each ...
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1answer
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Gravitationally bound systems in an expanding universe
This isn't yet a complete question; rather, I'm looking for a qual-level question and answer describing a gravitationally bound system in an expanding universe. Since it's qual level, this needs a ...
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1answer
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Speed of Universe Expansion [duplicate]
How much is the universe expanding every second (Earth second)?
If you could be a bit simple in the answer that would be good.
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At what speed does our universe expand?
Conceivably it expands with the speed of light. I do not know, but curious, if there is an answer. At what velocity, does our universe expand?
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Why the temperature is getting lower when the universe is expanding
As we know, if an ideal gas expands in vacuum, as its energy is unchanged, the temperature remains the same. An ideal gas's energy does not depend on volume. In general, the energy is $kT$ times the ...
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1answer
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How do we know space is expanding when we are part of space? [duplicate]
From what I understand space itself is expanding, and the Big Bang attempts to describe this expansion at the very early stages of the universe.
This is usually described in a visual way as 2 dots on ...
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1answer
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What is the age of universe? [closed]
As we know at the time of big bang as mentioned by the scientist the universe expanded faster than the speed of light. So does it mean that at that time all the particles present travelled in the time ...
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2answers
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Is time speeding up due to the expansion of space?
If we just look at our local galactic cluster, if all of the galaxies that are a part of it are moving away from each other, and so the overall 'density' of the strength of gravity in the cluster is ...
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0answers
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Where is universe expanding? [duplicate]
According to many physicist space, time and universe came to existence after the big bang. The universe is now expanding since after the big bang continuously. So my question is where our universe id ...
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4answers
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Origins of the universe questions
If the universe is expanding, what is it expanding into?
Similarly when the big bang happened where and how did it occur? - Where did the energy come from? Energy can not be created or destroyed does ...
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Is the speed of light the ultimate speed limit? [duplicate]
As we all know nothing can go faster than the speed of light as mentioned by most of our pioneer's in physics. But as I was listening to one of the statements of Sir. Stephen Hawkins he stated that at ...
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1answer
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Superluminal expansion of the early universe how is this possible?
Is this a postulate? I get the expansion of the universe, the addition of discrete bits of space time between me and a distant galaxy, until very distant parts of the universe are moving relative to ...
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1answer
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acceleration of the universe
Moments after the Big Bang, the universe was expanding at an incredible rate, (I've heard) faster than the speed of light. Due to dark energy, scientists predict the rate of expansion will pick up ...
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Universe is expanding at enormous speed
I'm not an expert but I've come to understand that the universe is expanding at enormous speed. That means that all of the visible galaxies are moving away from us at great speed.
I also came to ...
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1answer
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Redshift and shapes of galaxies
How does peculiar velocities lead to the observed elongation of galaxy clusters in redshift space, otherwise known as the Fingers of God effect? I have read the relevant Wikipedia page, but cannot ...
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1answer
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Universal expansion faster than the speed of light
If the universe is expanding faster than the speed of light, and force carrier particles move at the speed of light, wouldn't this cause infinite universal expansion? Since no forces would be acting ...
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3answers
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Redshift of light in dark matter
Following Edwin Hubble, it is widely believed that the universe is expanding, which is based on the red-shift of light from distant objects. Can dark matter cause light to be red-shifted and make it ...
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1answer
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Time for Light to travel from most distant objects in universe
I understand that it is possible to detect the most distant objects in space over 13 billion light years away from us and that the universe is 13.75 billion years old.
Does this imply that there were ...
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1answer
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Cosmic bubble collision
I'm reading this review right now. The claim seems to be that when you have an expanding "false vacuum", finite size bubbles form due to phase transition (cause by finite action instantons) (which, in ...
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3answers
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Could metric expansion create holes, or cavities in the fabric of spacetime?
Is it possible for metric expansion to create holes, or cavities in the fabric of spacetime?
According to the Schwarzschild metric, the metric expansion of space around a black hole goes to infinity ...
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1answer
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How to understand movement in expanding universe?
I know that universe is expanding equally between every pair of points but it was a single point in it's very past... so I was wondering if we could locate this center point of universe. Now I know ...
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6answers
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Why are distant galaxies not actually tiny bits of matter?
Distant galaxies are said to be moving away from the Milky Way (and us) at speeds approaching the speed of light. Since Special Relativity tells us that any object moving away from us at a velocity of ...
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What evidence is there for the Big Bang Theory? [duplicate]
Possible Duplicate:
What has been proved about the big bang, and what has not?
I know the expansion of the universe is the most compelling but what else makes it so well liked and believed. ...
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3answers
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Is observable universe an explanation against Olbers' paradox?
First of all, let me tell you that I'm not a physicist but rather a computer scientist with a mere interest in physics at nowhere near a professional level so feel free to close this question if it ...
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5answers
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What is the extent of the universe?
Is there any realistic, understandable, provable (even in some extent) explanation/model for the extent of the universe?
What is its shape? and Why? I mean physical explanations not philosophical ...
