Daniel Robbins

The multiverse is a theory that suggests our universe is not the only one, and that many universes exist parallel to each other. These distinct universes within the multiverse theory are called parallel universes. A variety of different theories lend themselves to a multiverse viewpoint.Not all physicists really believe that these universes exist.

General relativity was Einstein’s theory of gravity, published in 1915, which extended special relativity to take into account non-inertial frames of reference — areas that are accelerating with respect to each other.General relativity takes the form of field equations, describing the curvature of space-time and the distribution of matter throughout space-time.

General relativity was Einstein’s theory of gravity, published in 1915, which extended special relativity to take into account non-inertial frames of reference — areas that are accelerating with respect to each other. General relativity takes the form of field equations, describing the curvature of space-time and the distribution of matter throughout space-time.

Many physicists feel that string theory will ultimately be successful at resolving the hierarchy problem of the Standard Model of particle physics. Although it is an astounding success, the Standard Model hasn’t answered every question that physics hands to it. One of the major questions that remains is the hierarchy problem, which seeks an explanation for the diverse values that the Standard Model lets physicists work with.

For most interpretations, superstring theory requires a large number of extra space dimensions to be mathematically consistent: M-theory requires ten space dimensions. With the introduction of branes as multidimensional objects in string theory, it becomes possible to construct and imagine wildly creative geometries for space that correspond to different possible particles and forces.

Photons are one of the fundamental particles of physics that physicists hope to explain using string theory. Einstein received the Nobel Prize not for relativity, but instead for his work in using Planck’s idea of the quantum to explain another problem — the photoelectric effect. He went further than Planck, suggesting that all electromagnetic energy was quantized.

The problem of extra dimensions continued to plague string theory, but these were solved by introducing the idea of compactification, in which the extra dimensions curl up around each other, growing so tiny that they’re extremely hard to detect. The mathematics about how this might be achieved had already been developed in the form of complex Calabi-Yau manifolds, an example of which is shown in this figure.

Einstein’s theory of special relativity has had far-reaching implications, but it has left open certain questions that string theory hopes to answer. It has altered our understanding of time and space. It provides a theoretical framework that tells us how gravity works, Einstein’s theory of special relativity created a fundamental link between space and time.

In a solution known to string theory as an Einstein-Rosen bridge (shown in this figure and more commonly called a wormhole), two points in space-time could be connected by a shortened path. In some special cases, a wormhole may actually allow for time travel. Instead of connecting different regions of space, the wormhole could connect different regions of time!