If the galaxies in the universe are simulated as points scattered over the surface of a balloon. The accelerated expansion of the universe is similar to the result of inflating a balloon at an ever-increasing rate
Avi Blizovsky
Israeli cosmologists have discovered evidence that the universe will continue to expand forever at an ever-increasing rate. Scientists have been trying for many years to come to a decision on the question of whether the universe will expand to a certain point, then its expansion will stop and it will begin to contract - or whether the expansion of the universe - that is, the galaxies moving away from each other - will continue forever.
However, recently Prof. Avishai Dekal and Dr. Eidit Zahavi, from the Rakah Institute of Physics at the Hebrew University, found evidence that shows that the speed of expansion of the universe will accelerate and increase to infinity. If the galaxies in the universe are simulated as points scattered over the surface of a balloon. The accelerated expansion of the universe is similar to the result of inflating a balloon at an ever-increasing rate.
Albert Einstein came up with a seemingly paradoxical idea in the theory of general relativity, according to which the force of attraction can turn into a force of repulsion at large distances. The force of repulsion causes an acceleration in the rate of expansion of the universe. Without a force of repulsion, acting in parallel with the force of gravity - an accelerated and eternal expansion of the universe is not possible.
At a later stage, Einstein withdrew from the idea and defined it as one of the mistakes of his life. But the results of the new study, published today in the scientific journal "Nature" show that Einstein was actually right.
The first hints of this were discovered a year ago by American scientists. They measured the rate of expansion of supernovae (exploding stars whose light can be seen from great distances) today, and compared them to 4 billion years ago. From the results of the measurements they concluded that the rate of expansion of the universe today is faster than its rate of expansion 4 billion years ago.
Dekel and his colleagues went one step further. They analyzed the flow velocities of the galaxies in different directions, beyond the uniform expansion speed of the universe, and were able to use them to map the distribution of "dark matter" in a large area of the universe. It is an invisible substance with mass, whose gravity affects the rate of progress of galaxies (if its gravity is strong, the rate of expansion will slow down).
Their conclusion is that the average mass density in the universe is relatively large, and therefore the force of gravity acts very powerfully even between galaxies at great distances.
When this figure is applied to the equations dealing with the force of repulsion, the conclusion is that the force of repulsion will also be large (like the force of attraction, because they are balanced forces). "The combination of the two results unequivocally indicates that the force of repulsion acting at large distances is strong," says Prof. Dekel. According to Dekel, there is still no conceivable explanation for the discovery that opposite forces of attraction and repulsion operate in the universe, which balance each other and operate with such great power. "The new clues are very interesting and surprising and present a new and surprising challenge to physicists."
{Appeared in Haaretz newspaper, 16/9/1999{
The Hidan site was part of the IOL portal from the Haaretz group, Avi Blizovsky was then a high-tech and science reporter for the Haaretz newspaper.
