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EncryptedKnight
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Why did dark energy overcome dark matter to create the expanding universe we live in today?
It didn't.EncryptedKnight said:Why did dark energy overcome dark matter to create the expanding universe we live in today?
Chalnoth said:It's just not at all true that dark matter and dark energy are opposing forces that were close in strength. And Einstein certainly never said it (as the term dark energy wasn't coined until after his death).
Einstein's original idea of a cosmological constant was conceived because Einstein thought the universe should be static. He used the cosmological constant to balance the matter (dark matter wasn't known at the time, either). The idea there was that matter tries to fall inward, causing the universe to collapse. The cosmological constant pushes outward. So if you have a matter density and cosmological constant that are perfectly-balanced, then you can have a universe that neither expands nor contracts.
The problem with this idea, besides just being incorrect, is that it is unstable: a universe sitting in this configuration is just at the boundary of collapsing into a singularity or expanding forever. All it needs is for a little bit of matter in one region to migrate to another, and the whole system destabilizes.
So this idea of dark energy balancing dark matter was never a viable model. It wasn't a good idea to begin with, and it certainly never described our universe.
guywithdoubts said:Einstein didn't come up with the idea of dark matter, he came up with the cosmological constant previously mentioned. That'd be dark energy. And you are completely forgetting inflation.
You've still got a rather confused notion of what dark matter and dark energy do.EncryptedKnight said:I don't care how good of a model it is or isn't to another person, that is irrelevant as well. The fact is that Dark Matter has a small impact on the universe where as Dark Energy has a significant impact. In these terms they could be considered to have opposites properties, although technically not opposite forces I suppose.
All I know is that at some point in the beginning of the big bang, Dark Matter and Dark Energy had opposite properties which affected the universe to expand. The properties contained with Dark Matter and Dark energy are dynamic and unfixed.
It's entirely relevant, because your question makes no sense at all when applied to our universe.EncryptedKnight said:By the way, this is a theory and not a statement demanding to be a fact. Nothing can be proven wrong or right. "Incorrect" is irrelevant.
Chalnoth said:Neither dark energy nor dark matter is responsible for the fact that the universe is expanding.
guywithdoubts said:I thought dark energy was, in the form of the cosmological constant
relativity implies that time's passage is a chimera... all that is real is the whole history of the universe laid out at once? That point of view, the block-universe perspective, led Albert Einstein to declare in a letter to the family of his friend Michele Besso that the "distinction between past, present, and future is only a stubbornly persistent illusion."
Quds Akbar said:One of space's properties is that it can expand, and that means it contains Dark Matter
Quds Akbar said:dark energy let's space expand
But Dark energy allows for it and this is one case. But how can space expand without dark energy or the cosmological constant? And I meant Dark Matter, it was a typo, by the time you read this I would have fixed it.PeterDonis said:This is not correct; the expansion of space does not require dark matter to be present.
This is not correct either; space can expand without dark energy being present.
Quds Akbar said:how can space expand without dark energy or the cosmological constant?
Dark energy and dark matter influence how expansion changes over time. But a universe can easily expand (or contract) with either, given the right initial conditions.Quds Akbar said:But Dark energy allows for it and this is one case. But how can space expand without dark energy or the cosmological constant? And I meant Dark Matter, it was a typo, by the time you read this I would have fixed it.
ericore said:dark energy has the lowest density
ericore said:Volume determines expansion.
Think of an air balloon.
What determines how big the balloon is; the volume of air.
This is incorrect and very confused. Sean Carroll made a blog post a little while ago that does a good job of explaining how dark energy relates to the expansion of the universe:ericore said:Very simply because dark energy has the lowest density and the most volume/quantity.
Volume determines expansion.
Think of an air balloon.
What determines how big the balloon is; the volume of air.
Dark energy and dark matter are two of the biggest mysteries in the field of astrophysics. Dark energy is a theoretical form of energy that is thought to make up about 68% of the total energy in the universe. It is believed to be responsible for the accelerating expansion of the universe. On the other hand, dark matter is a type of matter that does not emit or absorb light, making it invisible to telescopes. It is estimated to make up about 27% of the universe's total energy.
Although they cannot be directly observed, scientists have gathered evidence of the existence of dark energy and dark matter through various astronomical observations. For example, the observation of the cosmic microwave background radiation and the rotation curves of galaxies both support the presence of dark matter. Additionally, the accelerating expansion of the universe is believed to be caused by dark energy.
This is still a topic of debate and research in the scientific community. One theory suggests that dark energy is a property of space itself and it causes the expansion of the universe to accelerate. On the other hand, dark matter is thought to have a gravitational pull that slows down the expansion. Therefore, as the universe continues to expand, the influence of dark energy becomes more dominant.
Yes, there are other theories that have been proposed to explain the expansion of the universe. One alternative theory is modified Newtonian dynamics (MOND), which suggests that the laws of gravity may need to be modified at large distances. Another theory is the holographic principle, which proposes that the information in the universe is encoded on its boundary rather than within its volume.
The existence of dark energy and dark matter challenges our current understanding of the universe and the laws of physics. They also have significant implications for the fate of the universe. If dark energy continues to dominate, the universe will continue to expand at an accelerating rate, leading to a "big freeze" scenario. However, if dark matter has a stronger influence, it could eventually slow down or even reverse the expansion, resulting in a "big crunch" scenario. Further research and exploration are needed to fully understand these mysterious components of the universe.