No need for "dark energy", gravity will suffice.

Chronos

Assuming there is nothing 'outside' the universe, pushing is the only apparent option.

LostUpNorth

Interesting point. I'd be very interested in any work that analyzes whether or not there could be something at the edge or outside of the universe. That analysis may prove or disprove dark energy quite well.

As I said, I'm not well versed in the field, but to me it's simple. If dark energy is acting as some sort of cosmic wind that pushes things in a direction away from a point, then our orbiting galaxies and planets should show some measure of change as they head "into" the wind. Imagine trying to fly an airplane in a circle on a windy day. On the down wind side the plane will go faster and on the upwind side it goes slower. To get a true circle you must constantly adjust the rate of turn. If you keep the same rate of turn your plane will spiral along in ellipses as the wind pushes you farther and farther along.

If indeed there is dark energy pushing our galaxy away from some location at an ever increasing speed, we should be able to measure acceleration AND deceleration within the galaxy as well. Quite simply, the up wind stuff should be going slower than the down wind stuff.

Hal King

Nearly all the "idea" of 'dark energy' is based on the apparent acceleration seen when comparing data and models to an 'empty model' -- the Milne model.

Problem is: What if this is simply due to a 'quirk' in the Milne model? It is known to be wrong so why is this 'acceleration hump' being used as a reason for 'dark energy'?

Seems far more likely that its simply a shortcoming of the Milne -- and likely Standard Model.

Hal King

I'm wondering what your distinction is between 'illogical' and 'mathematically inconsistent'? Is this intended to be some 'workaround' for cause and effect?

My view is different. Math is the language of science. When its found that a new 'word' is needed to explain the science -- a new 'word' (or math) is invented or found.

Science is in the concept not the details. Math and data are the way science is 'proved' -- it is NOT the science itself.

Math is NOT a requirement of science. Math is ONLY a more precise language or way of communicating the science.

Chalnoth

This would be all well and good, except that it turns out that pursuit of "mathematical beauty" has been an extraordinarily useful tool in discovering new theories. By mathematical beauty here I mean finding ways to write down the behavior of whatever is being considered in as few mathematical statements as possible.

Then there's the simple argument that a mathematical structure is any structure which is strictly-defined and fully self-consistent. Clearly the universe exists in one way and one way only, and is also self-consistent, so it stands to reason that the universe is, at its heart, mathematical.

Finally, when you stray away from using mathematics to describe the behavior of the universe, you invariably end up with ambiguities and inaccuracies. Plus you can't effectively work out what the consequences of statements about the universe are without mathematics. As a result, one cannot do science without mathematics.

Hal King

Reminds me of the old 'every logical or mathematical system is either incomplete or contradictory'.

Math is a minor player in science -- a useful tool -- similar to engineering or taking measurements.
You have to have it, have to use it, but it is NOT the primary focus or goal.

When the math fails the concept there are TWO possibles:

1) Bad concept
2) Bad math

Before you give up on the concept its best to recheck the math -- or even create a new one if needed. Math 'proves' nothing on its own. Might be interesting to some -- even 'beautiful' -- but that is a personal view that does not effect the science.

Also, I don't see why the universe only has to exist in one way? Maybe only be perceived in one way at a time -- again a viewpoint issue.

Chalnoth

Then why has taking it as fundamental proven so useful?

Hal King

Didn't say it wasn't useful ... only that the math is not the real point.

Chalnoth

That's not what I asked. I didn't ask why mathematics is useful. I asked why taking mathematics as fundamental has proven useful.

Hal King

Again that has not been fully determined as yet in cosmology. Might just as well be leading us in entirely the wrong direction.

Chalnoth

It has already been shown to be extraordinarily successful in cosmology, where prediction after prediction has been borne out with stunning precision.

Chronos

The fundamental evidence for dark energy came from the Perlmutter supernova study. See, for example: http://arxiv.org/abs/astro-ph/0309368

mehul ahir

what is the meaning of the nost incomprihensive thing about the universe is that it is comprihensive give detail meanig of it

Hal King

Simple geometric corrections using other than Standard Model give better data fits with no acceleration. Of course, that won't stop 'big science'. Too many careers are now tied to the concept. So something that will be given the label 'dark enegy' will eventually be found, no matter what the cost.

Chalnoth

Er, this is just false. You may potentially be able to fit some small subset of the data, but you can't match different observations without invoking some sort of modified gravity or dark energy.

Wallace

This kind of qausi-conspiracy theory stuff is just non-sense. Have a look at cosmology pre-prints, here. You will find a very active field with all kinds of different new ideas looking at dark energy and ways to fit the data with all kinds of other theories. The idea that 'big science' is stuck on one idea that it refuses to let go of is simply not supported by the evidence of just looking at the variety of ideas being out there (and not simply ignored).

Anyone working in cosmology would love to find a better theory than what we have at present, I gaurantee you that there is not a single person whose career would not benefit by overturning the current standard model of cosmology, which is why so many people are working so hard to do just that. The fact that the standard model has held up very well despite continued efforts to find problems with it just tells us that something about the model is very powerful, even if ultimately the physics behind it turn out to be rather different from what we currently suspect.

On the other hand, Bad new ideas that are based on simple misconceptions and don't consider the totality of the evidence available are, of course, ignored. That doesn't mean that there isn't a lively and open debate going on with regards to genuinely interesting alternatives.

Hal King

Actually, all you can say for any model is whether it matches data or not. The importance of an 'accepted' model is that it determines what will be used for further work ... grants, money, careers, promotions, etc. So if you are 'in the business' you have to use the accepted approaches.