Revolutionary discoveries move science forward. However, as in history, those who won the revolution and ascended to the throne will sooner or later be overthrown by a new revolution. This is precisely the situation that now threatens the theory of relativity, proposed by Albert Einstein, which reigned for more than a century. Reflections on this are published by LiveScience.
Instead of the theory of gravity of the Earth, the great physicist discovered gravity as the effect of curved space. He stated that all objects in the universe are inside a four-dimensional fabric called space-time. The discovery of gravitational waves six years ago proved his theory’s claim to the throne. Still, it may soon be overthrown by quantum theory.
The quantum world is very strange. For example, some objects can be in 2 places at the same time. This was very well explained to the world by Erwin Schrödinger and his cat. However, this perception of the world is not compatible with the smooth fabric of space-time.
Physicists are looking for a way out of this situation, trying to find a way to “reconcile” the two theories. The most popular one is string theory. Its essence is that electrons and quarks are created from vibrating strings. At the same time, original combinations of strings create unique particles. The plus side of this idea is that it reconciles general relativity and quantum physics. Theoretically. However, to make it work, the strings must “sound” in 11 dimensions, 7 more than Einstein proposed. There is still no evidence for the existence of other dimensions than the 4 discovered by the great physicist.
Some scientists in search of a compromise have turned to loop quantum gravity. It nicely reconciles two seemingly incompatible theories, provided they abandon the idea that space-time is a smooth continuous fabric. They concede that space-time is composed of a series of loops, and that it has structure on the Planck scale. The appeal of this theory, called modular space-time, is that it can solve a long-standing problem in theoretical physics concerning what is called locality and a notorious phenomenon in quantum physics called entanglement.
All of this may sound completely incomprehensible to most people, but the coherence of these theories has the most direct impact on our daily lives. We sit in space, we travel through time, and if something changes in our understanding of space-time, it will affect not only our understanding of gravity, but quantum theory in general. In addition, all modern technology only works because of quantum theory. If scientists better understand the quantum structure of space-time, it will have a decisive impact on technology in the near future.