Our universe may have more than three spatial dimensions. However, they remain hidden from us. Scientists believe that a particle that carries gravity could help us find them.
Many dimensions
Scientists believe they can prove or disprove the existence of extra dimensions in our universe. Gravity will help them do this. In fact, it was gravity that led physicists to the idea that there could be more than three spatial dimensions in the universe.
It was proposed in 1911 by Theodor Kaluza to explain the so-called “hierarchy problem.” The fact is that gravity is the weakest of all four fundamental interactions. It is billions of times weaker than the others, and no one knows why.
The real reason may be that it acts in several additional dimensions in which the other three do not act, and which we do not feel at all, because interatomic bonds and all radiation are electromagnetism, which does not interact with additional dimensions.
Over the years, physicists have significantly refined Kaluzza’s assumptions. Something called string theory has emerged, suggesting that there are actually eleven dimensions in our universe. However, this is of little significance, since the existence of dimensions beyond the three known to date cannot be proven, and therefore, it is unknown whether this assumption is truly scientific.
Gravitons
Over the past few decades, physics has made several important advances. In particular, scientists have realized that if there is interaction, there must be a carrier particle. However, in the case of gravity, things are still not simple, because scientists still do not understand how to link it to quantum mechanics, but it is clear that ultimately there must be some kind of particle, called a graviton.
And if gravitons really exist, then they must obey the theory of relativity. These are massless particles, and they move at the speed of light. But when they “fall” into additional dimensions, which must happen if gravity acts in them, from the point of view of an outside observer, they must begin to move slower than light, and thus acquire rest mass.
Gravitons have not yet been detected experimentally. However, if they are detected in an accelerator, it will be necessary to carefully examine their masses. If there is a wide range of random values, this will indicate the presence of additional dimensions.
Provided by: www.space.com
