String theory - Brian Greene

Now, coming to Einstein's era,he postulated that,

• space time has got 4 dimensions(including time), (like Newton did), but he also managed to explain the how, which Newton couldn't.

According to Einstein, 

• without any matter on the fabric of space time, it appears to be flat and linear
•  when matter is present, this space-time fabric warps and curves around that matter, alongwhich gravity attracts.(check pic)

•  Theodor Kaluza, theorized that electromagnetism(just like gravity) exerts its effects as warps and curves in a 5th dimension (including time).
•  Furthermore, using the assumption of the existence of a 5th dimension, he could also successfully mathematically derive out, not only einsteins equation, but also the equation for electromagnetism.

 That is it formed the basis of a unified theory, where every other physical theories could be derived from.

• Oskar Klein, went a step ahead to postulate that there are relatively smaller dimensions which are curled up, located at a microscopic level of the larger dimensions.
• just like how an electric cable from afar seems to be single dimension, but for small ants on the cable, there are much more dimensions(clockwise/anticlockwise) to that cable than a single dimension as perceived by the observor.

• That is according to Klein, ultramicroscopic enlargement of the visible dimensions could lead to the demonstration of, curled up microscopic dimensions.(check image)

Coming to the present era,

• Superstring theory - Talks about the smallest, indivisible entity which makes up space.
• i.e. We know, matter is made of atoms, which is composed of a nucleus, a proton and an electron. We have even gone further and found that, these micro particles are made of packets of energy called quarks.

• According to string theory, quarks are actually constituted of dancing, filament like form of energy, which looks like a vibrating string.
• And these can vibrate in different patterns(frequencies), leading to production of different types of particles based on the vibrating frequency.

This is the ultramicroscopic landscape of the universe. The matter within matter.

• Mathematically speaking, a very fascinating result was obtained, while applying and trying to incorporate Newtons, Einstein's equations.
• The string theory equation holds true mathematically in a scenario involving 10 dimensions of space and 1 dimension of time(i.e. a 11 dimensional system), which has not yet being observed by man
• The discovery and exploration of these extra dimensions could also hold the answer to why the 20(actually 26) fundamental constants have such distinct values which are relevant to the decimal.

• The geometrical shape of the ultramicroscopic landscape, is called as Calabi Yau manifold, and is postulated to be one which folds in on itself.(see pic)
• The shape of the landscape is thought to be what determines how the filaments of energy vibrate.

• Since, we have only observed the existence of 4 dimensions(including time), but have mathematically figured out the existence of 7 more dimensions, many experiments are being conducted to empirically observe them.
• One such experiment, done in the large hadron collider, where, particles moving near the speed of light are allowed to collide head on, to see if any resulting debris (called as gravitan) enters into any of these unknown dimensions.(This is calculated by measuring the total energy before and after the collison, lesser energy after the collision implies energy has been lost somewhere).