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What Does Gravity Have To Do WithThe Expanding Universe?
#1
What Does Gravity Have To Do WithThe Expanding Universe?
I've read some (I suppose they were) scientists argue that there’s not enough gravity to reverse inflation and cause the universe to collapse back to where it was before the Big Bang.

Gravity affects matter, but according to ye ol’ raisin bread dough theory it’s not matter but space that’s expanding. Why would scientists use the properties of matter and gravity to understand something that has nothing to do with either?

If we understand the properties of “space” and what’s causing it to expand, we will be able to predict whether it will one day (or eon) collapse.
The god who allows children to be raped out of respect for the free will choice of the rapist, but punishes gay men for engaging in mutually consensual sex couldn't possibly be responsible for an intelligently designed universe.

I may defend your right to free speech, but i won't help you pass out flyers.

Those who can make you believe absurdities, can make you commit atrocities.
--Voltaire

Nietzsche isn't dead. How do I know he lives? He lives in my mind.
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#2
RE: What Does Gravity Have To Do WithThe Expanding Universe?
Gravity is like curry. Space is like chicken, if there is more chicken and less curry as in more space and less gravity then quantum fluctuations would vary on the molecular level and cause issues on entropy. The only way entropy wouldn't rise is by balancing the "chicken" and "curry" which obviously by effect affect the forever expanding of the universe aka "spices". So what do we understand from this?I have no idea what I'm talking about
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#3
RE: What Does Gravity Have To Do WithThe Expanding Universe?
It's dark energy (placeholder name for what we'll eventually determine it to be) that's pushing the Universe apart. Gravity, a feature of "simple" matter (vice dark matter) isn't strong enough to overcome dark energy, so the universe is expanding.

A few hundred people on the planet have a good grasp on that, so don't feel like you're missing a sandwich.
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#4
RE: What Does Gravity Have To Do WithThe Expanding Universe?
(February 4, 2018 at 7:42 am)Gawdzilla Sama Wrote: It's dark energy (placeholder name for what we'll eventually determine it to be) that's pushing the Universe apart. Gravity, a feature of "simple" matter (vice dark matter) isn't strong enough to overcome dark energy, so the universe is expanding.

A few hundred people on the planet have a good grasp on that, so don't feel like you're missing a sandwich.
I understand your explanation is quite clear.

However, I am the Rhonda and understanding doesn't mean I have no more questions.

Everything in the universe has a counterpart to balance it. If there's dark matter, why isn't there dark gravity to balance dark energy? Why is dark energy the only thing in the universe that has no counterpart?
The god who allows children to be raped out of respect for the free will choice of the rapist, but punishes gay men for engaging in mutually consensual sex couldn't possibly be responsible for an intelligently designed universe.

I may defend your right to free speech, but i won't help you pass out flyers.

Those who can make you believe absurdities, can make you commit atrocities.
--Voltaire

Nietzsche isn't dead. How do I know he lives? He lives in my mind.
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#5
RE: What Does Gravity Have To Do WithThe Expanding Universe?
(February 4, 2018 at 9:52 am)Rhondazvous Wrote: Everything in the universe has a counterpart to balance it. If there's dark matter, why isn't there dark gravity to balance dark energy? Why is dark energy the only thing in the universe that has no counterpart?
Why do you think that's a rule?
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#6
RE: What Does Gravity Have To Do WithThe Expanding Universe?
Gravity is a curvature of spacetime. The amount of that curvature affects how space is different from one time to another: in other words how fast space expands.

In particular, the equations describing the expansion of space are, at base, the equations of gravity applied to the universe as a whole. The rate of change of the expansion is determined by how much matter and energy there is (this includes dark matter and dark energy). Each component of the energy balance: regular matter, dark matter, radiation (light), dark energy has its own contribution to gravity because of how the density of each is affected by that expansion. That, in turn, determines the rate of expansion.
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#7
RE: What Does Gravity Have To Do WithThe Expanding Universe?
(February 4, 2018 at 7:16 am)Rhondazvous Wrote: I've read some (I suppose they were) scientists argue that there’s not enough gravity to reverse inflation and cause                the universe to collapse back to where it was before the Big Bang.

Gravity affects matter, but according to ye ol’ raisin bread dough theory it’s not matter but space that’s expanding. Why would scientists use the properties of matter and gravity to understand something that has nothing to do with either?

If we understand the properties of “space” and what’s causing it to expand, we will be able to predict whether it will one day (or eon) collapse.

Think of it this way, expansion of space is like water flowing outwards.

Gravity can propel mass to move through space. It is as if the masses floating in water, while subject to the force of the moving water, also move independently through the water, as if propelled by stretched rubber bands attached to each other.

As soon as the Big Bang occurred, space streams outwards at high velocity. But the gravitational attraction of all mass with each other also caused all the mass to grandually start swimming against the flow of the expansion of space in an attempt to come together. However, When the masses first start to move against the expansion of the universe, the initial speed of the expansion of the universe is still dominates, so masses are still moving away from each other, as they move further from each other their mutural gravitation weakens, so the force propelling them to move against the flow weakens.

The question is, were there enough mass in the universe such that, before the flow of expansion of the universe carries the masses so far from each other that their mutural granvitation weakens to the point of being no longer capable of overcoming the pressure of the outward flow of space, the gravity can already completely cancel out the effect of the outward flow and cause all mass to come together against the current of the outward flow?

The answer is no. Gravity is causing masses to move against the current of the outward expansion of space, but not fast enough so that the the outward velocity of the masses will come to zero before the objects are carries so far apart by the expansion that mutural granvitational attraction will go to zero.

Where does dark energy come in? In our analogy, in the classical model of Big Bang, the outward flow of space is constant. If there were no granvity pulling masses together, then after the Big Bang, the universe will expand for ever at constant velocity, and all masses will move away from each other at constant velocity.

But in reality, the outward flow of the universe is accelerating. Even as gravity attempt to propel masses to move upstream against the the flow of,the expansion of the universe, the flow is actually getting stronger and faster. The mysterious force that accelerates the outward flow is called dark energy.
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#8
RE: What Does Gravity Have To Do WithThe Expanding Universe?
(February 4, 2018 at 9:53 am)Gawdzilla Sama Wrote:
(February 4, 2018 at 9:52 am)Rhondazvous Wrote: Everything in the universe has a counterpart to balance it. If there's dark matter, why isn't there dark gravity to balance dark energy? Why is dark energy the only thing in the universe that has no counterpart?
Why do you think that's a rule?

Interesting question.

In fact, the universe is the ONLY thing that's expending. Electrons aren't moving away from their respective nucleons. planets aren't moving away from their respective suns. Stars within a galaxy aren't moving away from each other. Only galaxies are moving away from one another, e r go, the raisin bread dough model.

so, yes, it's possible for dark energy to be the only thing that has no counter, not as a rule, but just the way things are.

In time we may move so far from other galaxies that we think we're the only one. Or we may move into the viciiity of another universe and not realize it's another. How will astrologers explain the weird constellations?
The god who allows children to be raped out of respect for the free will choice of the rapist, but punishes gay men for engaging in mutually consensual sex couldn't possibly be responsible for an intelligently designed universe.

I may defend your right to free speech, but i won't help you pass out flyers.

Those who can make you believe absurdities, can make you commit atrocities.
--Voltaire

Nietzsche isn't dead. How do I know he lives? He lives in my mind.
Reply
#9
RE: What Does Gravity Have To Do WithThe Expanding Universe?
(February 4, 2018 at 11:00 am)Rhondazvous Wrote:
(February 4, 2018 at 9:53 am)Gawdzilla Sama Wrote: Why do you think that's a rule?

Interesting question.

In fact, the universe is the ONLY thing that's expending. Electrons aren't moving away from their respective nucleons. planets aren't moving away from their respective suns. Stars within a galaxy aren't moving away from each other. Only galaxies are moving away from one another,      e r go, the raisin bread dough model.

so, yes, it's possible for dark energy to be the only thing that has no counter, not as a rule, but just the way things are.

In time we may move so far from other galaxies that we think we're the only one. Or we may move into the viciiity of another universe and not realize it's another. How will astrologers explain the weird constellations?

Not sure I said "no counter". Dark matter and dark energy are the two most common elements of our universe, 90% according to the articles I've seen. So if something exactly neutralized dark energy in an amount equal to whatever force it is producing, then there would still be 80% of the universe to keep the expansion going.
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#10
RE: What Does Gravity Have To Do WithThe Expanding Universe?
One way to look at dark energy is as the 'energy of empty space'. So, when space expands, there is more space, and hence more dark energy.

This extra energy has to be balanced, yes, but it is balanced by a decrease in the curvature of spacetime, which accelerates the expansion of space.

For ordinary matter and dark matter, when space expands, the total amounts of matter stay the same, but it is spread out more. This serves to gradually slow expansion.

For radiation (like light), expansion actually decreases the total amount of energy, which slows the expansion more.

So, in the very early universe, which was radiation dominated, the expansion was slowing, decelerating fairly fast. Later, when matter dominated, the expansion was still slowing, but not as fast. Now, with dark energy dominating, the expansion has started to accelerate. it's all a play-off between the different components of the universe and how the respond to expansion. And that is all about gravity.
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