Thread: Theory about Dark Energy and Expansion of the Universe.

I've been thinking about this for a while, and finnaly I found a place to talk about the idea.

Could this Dark Energy be, in fact, Gravity?

Example: We are aware that due to the distance from the Sun to the Earth, light takes about 8 minutes to travel. Since gravity can't travel faster than the speed of light, it takes 8 minutes to reach the Earth. So, the gravity we feel from the Sun, is actually the gravity from the Sun-eight-minutes-ago.

That means gravity from the past acts on the present.

If we take that to inter-stellar interaction inside a galaxy, the concept could explain why galaxies have less mass than expected (gravity from the past binding it together). It could even explain the expansion of the universe and why it is accelerated.

I am just an astrophysics enthusiast, have no degree in physics YET, since I'm young (19). Have no idea about the math behind this to test the theory; all I have is the idea. If someone find this theory worthwhile and can do some math, please contact me on e-mail and/or reply with critics.

Thank You.

The idea of dark energy is that it is an explanation as to why the universe is expanding faster than it was several billion years ago. It is not to be mixed up with dark matter which is believed to be hidden mass which holds galaxies together.

As to expansion, then over time everything would be further apart so less gravity pull on a universe where everything is further apart, so expansion would naturally speed up anyway.

The point about gravity is that like photons, it travels on and on. As a light beam spreads out and gets diffuse so eventually you cannot see it since you cannot pick up an ever smaller amount of photons with your eyes, so gravity spreads out in a similar way so no gravitational pull is felt beyond a certain distance because it is too small to detect.

But not small enough for photons. If everything in the universe causes gravity, then the universe is as full of "old gravity" as it is "old photons". Gravity red shifting photons is indistinguishable from recession redshifting them. Maybe photons redshift just by travelling through space which is full of "old gravity" so red shift would not be due to expansion but due to distance travelled. It would also give a false redshift inside a galaxy, making it look like stars are moving far faster than they are. With slow stars, the present visible matter is sufficient to hold a galaxy together. Just an idea.

I have debated with mathematicians on various forums and what such knowledge seems to do is strait-jacket them. They lose all imagination and are just as interesting as a text book.

No one comes up with an all encompassing idea of everything overnight. Don't be afraid to refine ideas if new information comes along, and to test all information. If someone says you are wrong, it means nothing unless they can prove it. Insults are not proof. Parts of cosmology like the big bang are little more than ideas. Test it and you'll find it's many faults.

Originally Posted by Cyberia

The idea of dark energy is that it is an explanation as to why the universe is expanding faster than it was several billion years ago. It is not to be mixed up with dark matter which is believed to be hidden mass which holds galaxies together.

Yes. What I am proposing is that they're the same thing.

Sorry if i didn't make clear the relationship between the dark energy and dark matter.

This "Old Gravity" would explain how galaxies are bound together despite having less mass than what is expected.

As for the expansion. Let's try this. If we look further in space, we see objects that are not only distant from us in space, but also in time, since light has a finite and constant speed. What is the limit of distance/time we can look in space? 13.7 billion years ago would be the answer . What would we see? The Big Bang singularity? Where would it be?

Everywhere around us.

The idea is that that Oldest gravity should pull everything towards its source, which is not located in a fixed point in space, but spreaded all around us.

Please, keep replying. If you find flaws please show them. I will try to find evidence.

so you're implying that gravity is pulling from billions of tiny points spread throught space caused by the big bang.
so, if the big bang spread out the gravity from where it was would chang the direction from where it's coming from all the while still acting on us?
let me clarify, as matter and energy from the big bang theory spread out it "sent' out gravity to act on nearby objects and since the origin of this gravity was always changing , we can only now tell where it's changing?

strange, possible, just different, a new approach.

Fgil90. Sorry I couldn't get back earlier.

The problem with galaxies is the claim that they are rotating too fast so should fly apart but there is hidden mass (DM) which stops this happening. However look at any galaxy or cluster and it is shaped as though there were only light matter (stars, etc) and there are no anomalous shapes caused by unseen dark matter which could be six times as much as light matter.

DM has serious problems in that no one is willing to guess what it is, oir even what it's properties are other than what is required of it. If it formed large structures, then stars and black holes would literally hoover it up as they moved about in galaxies. Also there would be sufficient that I think we would be able to see it as we see the effects of dust in space, no matter how finely spread out it is. It makes a lot more sense that galaxies are rotating more slowly.

As to expansion, that too is solved by photons being redshifted by gravitational drag (since they cannot lose speed, they lose energy) over time so it is a measure of distance. As to distance, if you take that as 13.7 billion light years, that comes out to 13,700 sections of one million light years in distance. Now divide that into the maximum possible speed, so 186,282 divided by 13,700 and you get 13.6 miles per second (for each million light year section) which is about the figure for expansion of the universe.

Now to the big bang. You get a singularity that even Hawking no longer believes in. It comes from where? It is ultimately dense which means that it is ultimately stable forever. However through magic it inflates at an impossible faster than light speed. Matter is created and it continues to ignore science by ignoring the basic laws of gravity. It miraculously slows down below light speed expansion. This is a four physical dimension expansion (a hypersphere) since if it were only three physical dimensions, it would have a point of origin and it would end up as a shell of material expanding away from that central point. However with the hypersphere (the universe as a 3D skin on a 4D ball), there is no centre and there can be the uniform expansion needed for the idea. However, so far there is no evidence of a fourth physical dimension and being a hollow sphere, what would be inside it?

The CMB is said to be the remains of the big bang but the problem there is that it should be at 3,000.C and then as proof, we should be able to look at space near there and detect a cooler temperature and ever cooler temperatures as we get nearer us till the universe has cooled down to it's present 2.7K. However, all we see is 2.7K. Some will claim that the figure is adjusted for redshift but no one points to a very distant cluster and says it's temperature is just 100.K because of it's distance. People give correct temperatures on it.

As to "the oldest gravity" (whatever gravity is), it spreads out. It will become ever more diffuse over time so ever weaker as it travels ever further. think of gravity as many huge and powerful light bulbs put light years apart. Over time, their light will reach other places but will be very faint, as in the stars we see in the sky, just faint dots though they may be millions of miles across. So with gravity. It becomes undetectable at such distances because we have so many other gravitational sources around us, notably the Earth itself.

This unexplained anomaly may be of interest to you:


http://www.astronomy.com/asy/default.aspx?c=a&id=9657


.

Originally Posted by Fgil90

Example: We are aware that due to the distance from the Sun to the Earth, light takes about 8 minutes to travel. Since gravity can't travel faster than the speed of light, it takes 8 minutes to reach the Earth. So, the gravity we feel from the Sun, is actually the gravity from the Sun-eight-minutes-ago.

Thank You.

Only Matter (and... of course energy, like light) cannot travel faster than light. However Gravity doesn't appear to be either, no one knows exactly what it is. we can't see, touch or define it, only measure and experience it's effect.
(matter has weight, gravity doesn't, Energy dissapates over time, and reduces when used, Gravity appears to be everlasting and doesn't diminish over time)
Since gravity is neither Matter nor energy it's unlikely to be governed by the rules like lightspeed being a maxmum, Like everyone else, I have no idea how it works, but Gravity appears to be instantaneous over any length of distance (between galaxies for example)


If gravity obeyed lightspeed then, supposing a galaxy collided with another, despite that galaxy being double the size, we would still recieve the gravitational pull equivalent to the orignial galaxy until the light reached us...this doesn't happen, when a galaxies mass increases, so does it's pull on the universe

Originally Posted by Fgil90

If we take that to inter-stellar interaction inside a galaxy, the concept could explain why galaxies have less mass than expected (gravity from the past binding it together). It could even explain the expansion of the universe and why it is accelerated.

Explain. and I don't mean that to be condecending, I can't see where you're coming from, I'd love to know how you came up with that

also, Do galaxies have less mass than expected? I didn't realise we expected a galaxy to have a given mass

Booms:

Gravity is the distortion of space-time.
http://en.wikipedia.org/wiki/Speed_of_gravity
According to General Relativity, speed of gravity = c

As Cyberea said, the problem of galaxies is that they rotate too fast, so they should have more mass than predicted, otherwise, many stars would be launched away from the galaxy. My proposal is that this hidden mass is the "Old Gravity".

Cyberea:

I didn't understand if you are supporting my theory or contradicting it. As to expansion, can you explain your calculations?

zazzerak:

The idea is four-dimensional. This "Old Gravity" would be coming from everywhere at the same time, but the intensity of gravity would vary, of course. Especially considering the distance.

I would suppose that since the distance increase, gravity should be weaker as time passes, but when time passes, according to my theory, there is more old gravity to act upon the present. So the curve (Speed of Expansion vs Time) we should expect would be slow-growing in early ages of the universe, and rapidly expanding as more time passes.

Booms:
"(matter has weight, gravity doesn't, Energy dissapates over time, and reduces when used, Gravity appears to be everlasting and doesn't diminish over time) " quote

That is slightly incorrect, if you get down to elementary particles energy is weight, and gravity is a force, and therefore energy. also gravity's strength is affected by distance.
And I try to keep in mind that gravity is as weak a theory as the big bang, We put the pieces together and hope our educated guess is right. [/code]