Dark Energy

[Sayonara]

Please reread my posts and quote me where I said anything about the cosmological constant not existing.

 

the cosmological constant/ dark energy doesn't exist

 

Oh cruel irony.

[JaKiri]

I didn't say "hey' date=' this is scientific law: cosmologists are wrong"

I just presented a perfectly logical and probably true idea that was attained the same way the theory of relativity was.[/quote']

 

You're a lost cause, you really are.

[ydoaPs]

I was thinking the same thing about you. I never said that this thread was fact. actually, I said the opposite.

[Sayonara]

You're a lost cause, you really are.

Not really. He just didn't figure on how stringently people here might do things.

[5614]

cum on, back to the subject, stop taking the piss out of each other!

 

maybe it does exits maybe not.....

assuming that dark matter does exist... what could it be... any theories, considering it doesnt react with matter, how can it be a physical object?

[ydoaPs]

is that better? now it has a warning.

 

Dark matter and dark energy aren't the same thing. Dark matter is probably planets, asteroid belts, moons, comets, undiscovered black holes, ect.

[ydoaPs]

I just got an idea. What if there was no Big Bang. WHat if the expansion is the universes answer to gravity. You could say that the universe "wants" equelibrium, so maybe it is just compensating for gravity. I haven't anywhere near thought this all the way out yet.

[JaKiri]

I just got an idea. What if there was no Big Bang. WHat if the expansion is the universes answer to gravity. You could say that the universe "wants" equelibrium, so maybe it is just compensating for gravity. I haven't anywhere near thought this all the way out yet.

 

Referring to things 'wanting' to get to another state is just shorthand for saying that lower energy states are more stable, and thus they are more likely to remain in that state having reached it. It's like ice and adding salt to it.

[ydoaPs]

I was thinking more like osmosis or thermal equelibrium.

[JaKiri]

I was thinking more like osmosis or thermal equelibrium.

 

Osmosis happens because there's more water going one way than the other; it's an equilibrium. I don't really see how 'galaxies moving apart' could be considered as part of an equilibrium.

[ydoaPs]

It could be an equilibrium for gravity. Gravity in one area equels expansion in another. That was the idea.

[JaKiri]

Fine as it goes, but nothing means anything in physics without mathematics to back it up, I'm afraid.

[TheProphet]

JaKiri: But without thoughts, ideas, theories and abstract thinking math would be of no real use to us..

[JaKiri]

JaKiri: But without thoughts, ideas, theories and abstract thinking math would be of no real use to us..

 

It's the other way round in physics, at least at present. Just about every interpretation of what goes on is because THE MATHS TOLD US, not the other way around. Things like black holes, and quantum uncertainty, and antimatter. The maths came first, the interpretation second.

[TheProphet]

It's the other way round in physics, at least at present. Just about every interpretation of what goes on is because THE MATHS TOLD US, not the other way around. Things like black holes, and quantum uncertainty, and antimatter. The maths came first, the interpretation second.

 

Most shurely but that is due to the scientific "language" is math! But without the ideas that lead to abstract thinking and math we wouldn't at this specific point we are (as you are saying)!

[ydoaPs]

Did I not say, that this isn't done yet? The Big Bang only comes from following the expansion backwards to one point. With this, there doesn't have to be a Big Bang. How would I extract the math for this to test it?

[MacM]

I just got an idea. What if there was no Big Bang. WHat if the expansion is the universes answer to gravity. You could say that the universe "wants" equelibrium, so maybe it is just compensating for gravity. I haven't anywhere near thought this all the way out yet.

 

Hi,

 

I'm new here and I just wanted to draw your attention to my first post:

 

http://www.scienceforums.net/forums/showthread.php?t=4934

 

It has bearing on your comments above.

 

It may be that:

 

1 - Dark Matter is very limited and not as prevelant as currently believed. Indeed probably negligable.

 

2 - Dark Energy doesn't exist as an exotic anti-gravity energy field.

 

3 - That gravity has a common function which inherently results in a different calculation of gravity that explains both the star rotational velocity anomaly at galatic scales (AD HOC Dark Matter solution) and the accelerating expansion of the universe (AD HOC Dark Energy solution).

[RICHARDBATTY]

I thought that the constant was a mistake or guess made to fill a gap in the theory that has now been proved wrong.

[RICHARDBATTY]

I thought that the constant was a mistake or guess made to fill a gap in the theory that has now been proved wrong.

[fermions]

do you mean the universal constant ( somethng like that ) ?

em... does the latest theory suggest it to be zero or not? it's really confusing...

[Martin]

do you mean the universal constant ( somethng like that ) ?

em... does the latest theory suggest it to be zero or not? it's really confusing...

 

I think you mean the "cosmological constant"

there's a thread about that' date=' and some other things, here

http://www.scienceforums.net/forums/showthread.php?t=5062

 

Primarygun, yourdadonopogos, and Cap'n Refsmmat

are the first three posters on that thread,

I got into it later on, and also Alexa, and also Sayonara briefly,

here is post #13 in that thread.

 

the cosmological constant was einstien's antigravitaional force to keep the universe static. dark energy is the MODERN version of it in which it is much stronger making up for the extra speed. in the future' date=' read a post before you comment on it.[/quote'][url']http://www.scienceforums.net/forums/showthread.php?t=5368[/url]

 

I dont remember who all else. It is a popular topic.

 

Alexa gave some links to NASA web pages andor

SpaceTelescopeNews web pages that tell about the

cosmological constant and dark energy IIRC.

 

I think she did anyway. I remember finding one she gave

pretty interesting

 

Since the topic is such a magnet it might be helpful to

have a central thread where people could put links to various

outside sources they think are understandable and reliable

[Martin]

as it originally appeared in the Einstein eqn (main eqn of Gen Rel)

the cosmological constant is a bit of extra curvature that isnt

caused by any corresponding concentration of energy

 

 

this was mostly ignored till 1998 when it was measured to be

one over a certain area

(curvatures are the reciprocal of area)

the area is the area of a square 9 billion lightyears on a side.

 

it is hard to comprehend a curvature so small, so close to zero

zero curvature would be

one over an infinite area

(in this kind of mathematics curvature is measured as reciprocal of area)

and to our minds a square 9 billion lightyears on a side seems like infinite

but it isnt

 

people exaggerate the importance of Einstein having said at one point that he thought he'd been mistaken to include this tiny autonomous curvature in his equation (which at the time nobody had measured)

 

maybe Einstein was being overly dramatic when he expressed regret. it is standard practice for mathematicians to put in some extra terms in the equation when you cannot logically exclude some possibility so whatever

his reason (his prejudice for a static universe at the time) it was not out of line. it was smart and even accepted practice. so let's not overdramatize the "Einstein's mistake" aspect---that is just something that appeals to popular imagination.

 

--------------

if you know how much one joule of energy is (raising a kilogram by about 10 centimeters, that much work, or dropping a kilogram 10 centimeters, that much thump)

then I can tell you how much extra energy would have to be spread out in space in order to give spacetime exactly the tiny extra curvature which

I said up there earlier

 

the extra energy would have to be 0.6 joule per cubic kilometer.

 

(that is the socalled "dark energy" density)

 

that amount of energy in every cubic kilometer of space would give to space the extra curvature which is

one over that very large area.

 

the rest of what one normally hears is to a considerable extent just hype, flap, journalists whooping it up in the media, and people masturbating their imaginations without much additional understanding

[RICHARDBATTY]

"people masturbating their imaginations without much additional understanding"

 

 

Thanks for the explanation and the strange image created by the later part of it.

[Martin]

Thanks for the explanation and the strange image created by the later part of it.

 

thanks for the response! It helps---always encouraging.

[TheProphet]

thanks for the response! It helps---always encouraging.

 

Yeah It's indeed a very GOOD summary!