OT: Gravity, Dark Energy, Universal expansion

[Renegade 13]

I was driving home from the city a while back, thinking about (of all things), gravity, dark energy and the expansion of the universe. I know, rather odd things to be thinking about on an hour and a half long drive, but hey, that's me.

The theory I came up with is this, of which I have no clue if it's possible, probable, or I'm just totally out to lunch.

Scientists have been searching for the cause of the increasing speed of the expansion of the universe for some time now, dubbing the force responsible for it "dark energy". Dark Energy Wikipedia Link My thought was...what if this expansion isn't caused by some unknown force, but instead is simply another aspect of an already familiar, but far from understood force. Gravity.

Everyone knows that, on the scale of us, our planet, our solar system, even super clusters of galaxies, gravity tends to reign supreme, holding everything in a relatively cohesive unit. However, it weakens as the square of the distance between two objects. So over massive distances, gravity from an object is essentially nil on another distant object. Unless I'm terribly wrong, gravitational force is currently thought to approach zero, but never actually reach zero (to become infinitely close, but never reach).

What if, instead of simply becoming incredibly weak over massive (billions of light-years) distance, gravity essentially reversed itself. It's look something like this...please excuse the horrible little graph, I whipped it up in about 3 minutes with Paint



So instead of a mysterious force permeating space, causing an expansion of increasing speed, gravity, once the universe expanded sufficiently from the Big Bang, would expand due to, of all things, the gravity that also holds it together.


Now, feel free to blow holes in my wee theory, in fact, I hope you do. I just thought it was an interesting idea, that's more than likely impossible. Though, we really don't have any idea of how gravity actually 'works', so...who knows!

[narf poit chez BOOM]

/me votes for 'Unprovable, a little silly, but a fun idea'.

[Solymr]

I voted that I like it, but what I mean is I like the idea that someone else thinks about this stuff like I do and as to why it might happen. I don't think the theory is solid, but a cool thought in any case.

[Mudshark]

Of course it is gravity! What was the Disney movie, outside of the black hole? The weird robot one? I am more thinking of traffic, or should I finally get XM? I have heard a theory that the moon stabilizes Earth, and it is slowly,flowing away. Why do I feel like I am living on a ping ball. Well we are, on a grand scale.....

[Randallw]

I too contemplate things when I drive only I concentrate on Philosophy and sociology. I suppose since I can't understand people's motivations I try to come up with reasons for things, but enough of that.

I have always thought Dark matter is a bit suss. Physicists were studying space and couldn't come up with a reason for what appeared to be, and this might be extremely exagerated, 95% of the universe's weight. It just seems to me to be cheap that they then explain

"oh well the thing is there is this thing called Dark matter that makes up all the extra weight, only we can't detect it or see it. It makes our sums add up though if we assume it exists"

Pity I wasn't taught such a thing in college.

"oh well on the face of it my math doesn't add up but you see there is an unseen variable that if included results in 1+1=3"

All I know of Gravity is that it is the weakest of the 4 forces. After all the entire gravity of Earth acts on us yet we can easily lift things, dependent on weight, and lift our own mass.

[narf poit chez BOOM]

A magnet less than an inch around can lift its own weight against the force of the entire earth. If memory serves, gravity is about a million times weaker than magnetism. On the other hand, gravity goes a lot farther than magnetism.

[dogscoff]

I think I may have heard this "gravity goes from pulling to pushing at extreme ranges" theory before, but I don't know if it was disproved or is still around or what. A bit of googlage may find someone who has done some work on it.

Mudshark said:
I have heard a theory that the moon stabilizes Earth, and it is slowly,flowing away.

Actually, the moon is falling, very very gradually. Every orbit it gets a tiny bit closer to Earth. Eventually, it will drop out of the sky and crash into us.

Of course, that's a long long way in the future. In fact, I think the sun will move into the next phase of its life by then, expanding to scorch and swallow up the inner planets (including us) so you've got a good few billion years to worry about it yet...

[capnq]

Mudshark said: What was the Disney movie, outside of the black hole? The weird robot one?

That was The Black Hole.

[capnq]

dogscoff said:

Actually, the moon is falling, very very gradually.

No, it isn't. It's drifting away at a rate of 1.5 inches per year. The reason for this is conservation of angular momentum as the Earth's spin slows down due to tidal friction.

[Spoo]

Looks like a variation on MOND (http://en.wikipedia.org/wiki/Modifie...onian_dynamics).