Friday, April 20, 2007

Probing Warps

Once you can accept the universe as matter expanding into nothing that is something,
wearing stripes with plaid comes easy. ~Albert Einstein

Well, here's a news flash, if ever there was one. It seems that Einstein has been found to be right -- again. The BBC reported that the NASA Gravity Probe B satellite, in orbit for three years now, has confirmed that mass does, in fact, warp space.

I'm sure you've seen the two dimensional analog to this. You have a large ball resting on a rubber sheet. The ball causes the sheet to deform because of the ball's mass. Anything coming close enough to the ball follows the warp in the sheet and proceeds to sprial in toward the ball. Einstein's Theory of General Relativity predicts that three dimensional space is warped in the same way.

There's another effect as well. If the ball spins, it will drag the rubber sheet with it, ever so slightly. The more massive the ball, the more obvious the drag. General Relativity predicts this "frame dragging" as well as the warpage (geodesic effect). Gravity Probe B has provided evidence of the warp and could do the same from frame dragging, using the most precisely manufactured gyroscopes ever made. All that's left is to do some more serious number crunching.

Now one would think that physicists would be whooping it up over yet another proof of the beauty and accuracy of Einstein's theories. And perhaps most are at least quietly satisfied, but the BBC article says that Professor Tim Sumner couldn't resist the obligatory dig that "other tests could start to reveal cracks in General Relativity, suggesting where modifications might be made."

"There is an expectation that at some level we will expose a departure from pure general relativity as envisaged by Einstein," Professor Sumner is quoted as saying.

Now, I am certainly enough of a realist to recognize that anyone's theories, even Einstein's are subject to modification and outright disproof. But, few theories have managed to pass the test of time like Einstein's.

In this piece, I noted this article which, based on observations of a binary pulsar pair bore out not one, but three areas pf GR: Gravitational redshift, Shapiro delay, and gravitational radiation and orbital decay. And, if I were Professor Sumner, I wouldn't hold my breath expecting frame dragging to fail. Observations taken in 1997 appear to have confirmed the effect, based on X-ray observations of gas moving around a black hole.

I think sometimes that some physicists are so anxious to disprove Einstein because of his angst about quantum theory. Einstein didn't like quantum theory. No, I tell a lie: Einstein hated quantum theory. The concept of a probabalistic universe was anathema to him. Despite his revolutionary view of space and time, matter and energy, Einstein still saw the universe to be as deterministic as Newton had. As a result, Einstein spent much of his life seeking the Grand Unified Theory that would unite all the forces at all levels under one simple (at least to the average physicist) equation.

While he was bending his efforts to this, much of the world of physics passed him by. I think some scientists have held this against him, wondering what he might have accomplished has he embraced quantum theory.

Perhaps it's the light speed limit. We all want hyperdrive so we can start exploring the galaxy, but Einstein's imposition of the speed of light as an unattainable speed puts a damper on that sort of thing.

Scientists should keep on testing Einstein's predictions, of course, because we learn more about the universe in the process. But they shouldn't seem surprised when Einstein keeps coming up trumps. As for me, I'm going back to wearing stripes and plaids. When my wife complains, I'll tell her Einstein said it's okay.

Let's see if she can prove him to be wrong.

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