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Dark Energy Confirmed
bill_mcgonigle writes "By correlating the results of the Sloan Digital Sky Survey and the Wilkinson Microwave Anisotropy Probe, astronomers have confirmed the existence of dark energy.
While gravity attracts, dark energy repels, so by comparing the positions of millions of galaxies and their red-shifts with the temperature map of the early universe, evidence was found for dark energy on the scale of 100 million light years.
"Dark energy, whatever it is, is something that is not attracted by gravity" said David Spergel, a Princeton University cosmologist and a member of the WMAP science team.
"We are finding that most of the stuff in our universe is abnormal in that it is gravitationally repulsive rather than gravitationally attractive," said Albert Stebbins of the Fermi National Accelerator Laboratory. The universe is expanding at an accelerating rate, a switch that happened about 6.3 billion years ago, before which the expansion was decelerating."
Well here's one possibility. If that's possible, anything is.
Over 200 years ago massive objects were observed to attract each other and deflect a torsion balance in a direction at a right angle to the earth's gravitational field. So your interesting hypothesis (and I do like it) needs some modification.
Also, this particular article is about "dark energy", which is considered different from "dark matter". Not that it matters.
Larry
If you're interested in understanding this stuff, I highly recommend QED by Richard Feynman. It's cheap, a quick read, and accessible to anyone who's interested and has a high school education. It's accurate enough to be used in graduate-level physics courses, but is completely qualitative. I.e., there are no numbers or formulas but only conceptual calculations.
Rather than assuming some bizarre physics of gravitons where they pull something they ram into, why not take a simpler approach and assume that they push things along, just like a baseball and the milk bottle at the faire?
You appear to be using an overly-simplistic model of what force-carrying particles are.
The classical model of force involves "fields" - continuous distributions of force about their sources (e.g. an electric field that varies as the inverse square of distance from an object with charge, or a gravitational field that varies as the inverse square of distance from an object with mass).
When quantum mechanics came along, it was realized that these fields weren't continuous in all senses - disturbances in the field could only come in discrete packets. These are the force-carrying particles.
A graviton doesn't "ram into" anything. It's a moving ripple in the gravitational field of an object. The net effect of all gravitons (real and virtual) about an object with mass is to produce an attractive force on other massive objects nearby.
Similarly, a photon is a moving ripple in the electromagnetic field, with the net effect of all of the virtual photons in the vicinity of a charged object being to attract or repel other charged objects in the area.
The properties of gravitons are less certain, because it's hard to build a quantized version of Einsteinian gravity, but this is the general idea behind force-carrying particles (in force-carrying contexts, they can be thought of as the minimum (quantized) disturbance of a classical-looking field of force).
Actually, to be fair, particle theorists have been saying for quite a while that there should be a cosmological constant, (This is what Dark Energy essentially is). Unfortunately, particle physics currently has this constant many, many orders of magnitude too high. Really the major thing about Dark Energy is it is a reversal of the previously widely held contention in cosmology that the universe was decelerating, but this is not the first time that cosmology has been reversed like this however with the new precision of measurements like WMAP it might be the last time such a reversal occurs.
Now we've been decelerating...then accelerating?
This is the thing that has been driving me absolutely crazy vis-a-vis the Big Bang theory, is that the practitioners seem to operate under the maxim:
"Keep adding terms until the data fits"
That's not the way science is supposed to work.
We've had a fair share of juggling of terms, including:
- "Big Crunch" - gravity will let the universe collapse again
- "Flat Universe" - universe will expand forever, but keep slowing down
- "Inflationary Universe" - universe expanded faster than the speed of light for a tiny moment (addressing the age and isotropy problems)
- Not sure what to call this... "Second wind universe" - universe slows its acceleration before dark energy becomes the reigning cause of repulsion
I sincerely doubt it will end there - the Missing Mass problem and the Age of the Universe problem will push the equations incrementally.The Hubble telescope observations are getting awfully close to the predicted age of the universe. I wonder what age-of-the-universe estimate this new theory will predict; something more than 13.7 billion years?
The missing mass in the form of dark matter is, by all accounts, supposed to be mass that attracts; the inflationary universe theory depends on it for flatness. This might be another move 'around' the problem.
The Big Bang theory fell from grace for me over a period of fifteen years. While I don't subscribe to the notions of Velan, I'm curious, yet ambivalent about Alfven's plasma cosmology, there are a number of viable cosmological theories that don't have age, mass or exotic physics problems. It seems we closed the book on alternatives too soon, and are constantly interpreting data so it fits with theory, instead of breaking the back of theory on data.
Proving mathematically that you can never hit a wall must be tempered with observations of a hole in the wall and drunk in front of said wall on his back at a frat party :)
Binary geeks can count to 1,023 on their fingers
Actually, Mike, such a mechanism was proposed by George Lewis LeSage in 1784. The theory keeps on getting shot down, then revitalised in periodic cycles. There are those who have derived Newton's equations from this sort of paradigm, and there are those who have indicated that if gravitons (assuming such a particle is involved) go at the speed of light, there might be problems with orbits.
I prefer to wait and see on the subject. I'm just waiting for the book Pushing Gravity: New Perspectives on Le Sage's Theory of Gravitation to arrive for yet more "light reading" :)
Side thought: I think I got my don't-close-the-door-on-them attitude to these various theories from being a good debugger. If reality is anything close to the way debugging operates, the same symptom can have multiple causes, but any instance really has one cause...
...and it's hardly ever what any of your initial guesses were, regardless of how sensible they seemed. ;)
Binary geeks can count to 1,023 on their fingers