Monday, February 20, 2006

REMAKING NEWTON'S THEORY OF GRAVITY

Scientists from Scotland are turning the physics world on its head...
Newtonian physics can be used to predict the movement of the planets successfully, but the problem comes when it is used to calculate the movement of stars. Newton's formula was that the gravitational force of an object was equal to the gravitational constant multiplied by its mass and then divided by distance squared. The further away something is from the source of the gravity, the less powerful it is. At the edges of the universe, the force is so weak it is known as "nano-gravity".

Dr Zhao said: "If you use Newton's theory, you will find something very odd. The theory predicts the stars should be flying out of the galaxy, but in reality they are staying inside. Because people liked Newton so much, they put in dark matter in galaxies to keep the stars inside."

Where others add in extra mass to galaxies to hold them together, he and Dr Famaey were gripped by the idea that the gravitational constant could be "boosted".

"But how much do you want to boost it by? How do you put in a boost factor in a way that keeps the theory beautiful. It's a tricky thing," Dr Zhao said.

"Our aim was to put in the right amount of boost and still keep its intrinsic beauty... beauty meaning it doesn't violate fundamental principles.

"You need a large boost at the outskirts of the galaxy but you don't need that near the sun."

This required a gravitational constant that was anything but, and actually changed depending on where it was in the universe. This presented a fundamental problem. "There cannot be many laws of gravity. There has to be only one function that works," he added.
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