Is the Expansion of the Universe Uniform?

In summary, the rate of expansion appears to have varied over time, at first slowing down then, since the last 6bn years, speeding up again. However, the expansion is not even since gravitationaly bound objects, like galaxies, don't expand at all. Most of the Universe though is (almost) empty, no significant amount of matter and therefore gravity exists.
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I know that the universe is expanding since the beginning of time or at least the beginning of the universe it self. So I was wondering if the universe has always expanded evenly (some parts getting bigger while other grow not as fast) and if it doing so now??
The example in my head is like dropping die in water. The die on the outer edge will dissipate faster than the die in the middle of the drops. Or even some other kind of form of the idea.
 
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Overall, the rate of expansion appears to have varied over time,
at first slowing down then, since the last 6bn years, speeding up again.
However the expansion is not even since gravitationaly bound objects, like galaxies, don't expand at all.
Most of the Universe though is (almost) empty, no significant amount of matter and therefore gravity exists.
That is what is expanding, and at a given point in time the rate of expansion is the same everywhere,
 
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rootone said:
Overall, the rate of expansion appears to have varied over time,
at first slowing down then, since the last 6bn years, speeding up again.
Not quite. From what we can tell, the rate of expansion has done nothing but decrease. Early-on it decreased very rapidly, and less so more recently. The rate has been slowing down slowly enough over the last few billion years that objects have started accelerating away from one another.

If this is confusing, notice that constant expansion means a constant recession speed per distance, so as things get further, they move faster relative to one another.

This is why I refer to it as an "accelerated expansion" rather than "the expansion is accelerating".
 
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It suggests that as time goes forward, one variable increases while another decreases.
There is a moment when they have the same value, but there is no significance in that value.
 
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rootone said:
It suggests that as time goes forward, one variable increases while another decreases.
There is a moment when they have the same value, but there is no significance in that value.
What are you talking about?
 
  • #6
rootone said:
It suggests that as time goes forward, one variable increases while another decreases.
There is a moment when they have the same value, but there is no significance in that value.
Yep, you lost me on that one as well.
 

What is an evenly expanding universe?

An evenly expanding universe is a cosmological model in which the universe is expanding at a constant rate in all directions. This means that all galaxies and celestial bodies are moving away from each other at the same speed.

What evidence supports the theory of an evenly expanding universe?

The most significant evidence for an evenly expanding universe comes from observations of the cosmic microwave background radiation. This radiation is a remnant of the Big Bang and is found to be evenly distributed throughout the universe. Additionally, the redshift of distant galaxies is consistent with the idea of an expanding universe.

How does an evenly expanding universe affect the size of the observable universe?

An evenly expanding universe means that the observable universe is constantly increasing in size. This is because as the universe expands, more distant galaxies become visible to us. However, the speed of light is finite, so there is a limit to how far we can see. This is known as the observable universe.

What role does dark energy play in an evenly expanding universe?

Dark energy is a theoretical form of energy that is thought to be responsible for the accelerating expansion of the universe. In an evenly expanding universe, dark energy would be evenly distributed throughout space and contribute to the constant expansion rate.

Is there a limit to how fast the universe can expand in an evenly expanding universe?

According to the theory of relativity, there is a maximum speed at which objects can move, known as the speed of light. This means that there is a limit to how fast the universe can expand, and it is currently believed that the expansion rate is constant and not accelerating beyond this limit.

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