Want to stay on top of all the space news? Follow @universetoday on Twitter
Grand Unified Theory is a theory that seeks to accurately explain all physical phenomenons in the universe starting with the combining of the three fundamental forces, the electromagnetic force, the strong force, and the weak force. It can be considered to be a step towards the ultimate theory of Physics. It is famous for being the one concept that the greatest minds in the discipline have yet to accurately explain. So what is the big deal about grand unified theory and why has it been so difficult for scientists to come up with one?
The main difficulty lies with the two main branches of physics, classical mechanics and quantum physics. Both branches of physics deal with the motion of objects and the interaction of matter and energy. However the theories seemingly don’t complement each other. On the large scale, scientists have been able to use classical mechanics to explain the movement of everyday objects on Earth to entire galaxies. However these rules don’t apply perfectly at the microscopic and subatomic level. This is where quantum physics comes in. However the major problem is that if the building blocks of the universe are found in quantum physics, why can’t those rules be applied universally?
For the most part that has happened. For almost every major phenomenon physicists have managed to find the corresponding theories explaining them in classical mechanics and quantum physics and show the connection between them. This is how the understanding four fundamental forces were derived. However there is one last problem that not even Einstein could overcome and that concerns gravity. Gravity is the one force that cannot be properly explained. We know its effects but we don’t know its origin. Einstein described gravity as the result of the geometry of the fabric of space time. In short it’s simply a curve in space where a massive object is. However, when looking at gravity in terms of quantum physics the rules change. Every other force has a corresponding particle. So it would make sense that there is a particle for gravity.
In the end gravity is the last mystery that is preventing the emergence of a true grand unified theory. In the meanwhile there are many candidates such as string theory that seek to close the gap. However, the problem is that there is not enough physical data to back up the hypothesis. It is interesting to note that scientist have been able to prove every other aspect of physics from the photoelectric effect to special relativity, but still have not found the evidence to explain how gravity functions.
We’ve also recorded an entire episode of Astronomy Cast all about the Search for the Theory of Everything. Listen here, Episode 106: The Search for the Theory of Everything.