Questions about the origin and evolution of dark energy.

In summary, Dark Energy is produced by star activity and it plays a role in the acceleration of our universe. It has remained dormant for billions of years but has recently become more powerful. It is not related to "anti-gravity" and will cause the universe to expand exponentially in the future.
  • #1
K. Doc Holiday
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Dark Energy; origin and evolution

I have read the threads but I still have some unanswered questions about the origin and evolution of dark energy.

Has dark energy existed since the big bang? If so, why did it remain dormant for billions of years. Or did it spontaneously jump into existence later on?

If it was dormant then why did it suddenly become active?

Gravity pulls objects of mass towards each other. Dark energy pushes objects of mass away from each other. Is dark energy a reverse function of gravity? A type of anti- gravity?

Our 4 dimensional universe is continuing to pick up speed in an "outward" direction. Is dark energy getting more powerful or is the total amount of dark energy increasing over time? How is that possible?

I've read that the acceleration of our universe might be on an exponential curve. Does that mean someday all objects of mass will be flying outward from our point of origin and from each other at 99% of the speed of light someday?

Is that too many questions? Am I asking the wrong questions? My Dad encouraged my innate sense of curiosity by telling me there are no stupid questions. That got me into trouble in Sunday school. I hope it doesn't get me into trouble here.Doc
 
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  • #2
K. Doc Holiday said:
Has dark energy existed since the big bang?
As far as we know, yes
If so, why did it remain dormant for billions of years
This is a common misconception. It was not at all dormant. It was simply much weaker than gravity when the average matter density throughout the universe was high. About 6 billion years ago, it became roughly equal in effect and since then it has become dominant over gravity.

Gravity pulls objects of mass towards each other. Dark energy pushes objects of mass away from each other. Is dark energy a reverse function of gravity? A type of anti- gravity?
In effect yes, but do NOT think of it as "anti-gravity" that's a sci-fic concept.

Our 4 dimensional universe is continuing to pick up speed in an "outward" direction. Is dark energy getting more powerful or is the total amount of dark energy increasing over time?
The unit density of dark energy remains constant so the total amount increases with time.
How is that possible?
Good question.

I've read that the acceleration of our universe might be on an exponential curve. Does that mean someday all objects of mass will be flying outward from our point of origin and from each other at 99% of the speed of light someday?
No, it means that even objects within our Observable universe are ALREADY receding from us at about 3c. This is recession, not proper movement. I recommend the link in my signature.
Is that too many questions? Am I asking the wrong questions? My Dad encouraged my innate sense of curiosity by telling me there are no stupid questions. That got me into trouble in Sunday school. I hope it doesn't get me into trouble here.
No, it's not too many questions, but it really is better to focus on one at a time and move on to the next after you have absorbed the first one since it may answer some of the subsequent ones, as I believe you will see in this thread.
 
  • #3
K. Doc Holiday said:
Has dark energy existed since the big bang?
If dark energy is produced by star activity similar to neutrinos, it is possible that dark energy did not exist immediately after the big bang.
 
  • #4
Gerhard Mueller said:
If dark energy is produced by star activity similar to neutrinos, it is possible that dark energy did not exist immediately after the big bang.
No, it isn't . Gravity due to matter and radiation is attractive. This includes also neutrinos. In contrast to any source of gravity which is attractive dark energy exerts negative pressure.
 
  • #5
K. Doc Holiday said:
Our 4 dimensional universe is continuing to pick up speed in an "outward" direction. Is dark energy getting more powerful or is the total amount of dark energy increasing over time? How is that possible?
In this context "pick up speed" means accelerated expansion. What drives the expansion is not the "total amount of dark energy" but its density. And that is constant over time according to observational date we have till now. What happens is that while the dark energy density is constant the matter density is decreasing due to expansion. That means that the former becomes more and more dominant and will cause the universe to expand exponentially in the far future.
 
  • #6
timmdeeg said:
No, it isn't . Gravity due to matter and radiation is attractive. This includes also neutrinos. In contrast to any source of gravity which is attractive dark energy exerts negative pressure.
Do you have any argument that star activity does not produce dark energy?
 
  • #7
Gerhard Mueller said:
Do you have any argument that star activity does not produce dark energy?
You have that backwards. You are making an unsubstantiated claim that star activity produces dark energy. You need to substantiate that claim or retract it.
 
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  • #8
Gerhard Mueller said:
Do you have any argument that star activity does not produce dark energy?
Sure. We understand how stars work: nuclear fusion. We can replicate this process in the lab and understand it and measure it exactly. If dark energy was leaking out of these reactions, the energy equations would not balance, and they do. It's happened before that way, when physicists first started to calculate the energies of fission exactly, they did notice a minute amount of energy missing. We've since discovered that it was because a neutrino popped out. But that's it, once the neutrino was added, the equations balanced.

Stars are really not that exotic, astronomically speaking, they're pretty mundane. Just nuclear physics, not even any interesting degenerate matter yet.
 
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  • #9
Gerhard Mueller said:
If dark energy is produced by star activity

Please bear in mind the PF rules regarding personal theories.
 

Related to Questions about the origin and evolution of dark energy.

What is dark energy?

Dark energy is a theoretical form of energy that is believed to make up about 70% of the total energy density of the universe. It is thought to be responsible for the observed accelerated expansion of the universe.

What is the origin of dark energy?

The origin of dark energy is still a mystery and is currently being studied by scientists. Some theories suggest that it could be related to the expansion of the universe, while others propose that it could be a new fundamental force or a property of space itself.

How does dark energy affect the universe?

Dark energy is believed to be the driving force behind the accelerated expansion of the universe. It is thought to counteract the gravitational pull of matter, causing the expansion of the universe to speed up over time. This has a significant impact on the structure and evolution of the universe.

Can dark energy be observed or measured?

Currently, there is no direct way to observe or measure dark energy. Its existence and effects on the universe are inferred from observational data and mathematical models. Scientists are working on developing new methods and technologies to better understand and study dark energy.

How has our understanding of dark energy evolved over time?

The concept of dark energy is relatively new and our understanding of it is constantly evolving. It was first proposed in the late 1990s to explain the unexpected accelerated expansion of the universe. Since then, scientists have been gathering more data and developing new theories to better understand this mysterious force.

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