Understanding space time is the key to learn everything we know of our universe. Albert Einstein’s theory of relativity digs deeper into space time as it gives us a perspective about time dilation, speed of light, theory of general relativity, and the laws of physics.
Its Origin
Space and time were created during the big bang. When the universe was young, just after the big bang, space time was just a tiny bubble. Just after the big explosion, there was an instant inflation which forced the universe to expand. The universe is currently expanding at a rapid rate. Scientists believe that the expansion of the universe is so fast that it could easily surpass the speed of light. This is also known as space-time inflation.
This sudden expansion of the universe is something which has baffled astrophysicists. The expansion of space-time occurred about 10-23 seconds after the big bang. This happened so instantly that the speed of the expansion remains unknown till date. The laws of physics state that, no object of mass can move through the universe at the speed of light. However, the inflation of space itself doesn’t contradict the law as space doesn’t have mass.
So What is it About Einstein’s Theory of Relativity?
Einstein’s theory of general relativity discusses about the curvature of space-time. It clearly describes the geometry of space. Before Einstein, we believed that the universe obeyed Euclidean geometry. Which states that in the universe, parallel lines do not intersect and the sum of the angles of a triangle is 180 degrees. This means that we perceived the universe to be a single plane of existence where space and time cannot be bent or traversed.
However, this is not the case. As a Euclidean universe would only comprise of static objects of same mass. Albert Einstein’s theory states that the universe follows non-euclidean geometry where the angles don’t sum to 180 degrees and parallel lines can cross, intersect or diverge.
Space-time Curvature
Picture the universe as a piece of paper or cloth. Let’s say that you place an object of considerable mas on it. When you do so, the piece of cloth or paper will bend to support the mass of the object. Well! This is how space-time works. Gravity plays a vital role in this aspect as it is responsible to bend space and time. Without gravity, objects remain static and space time cannot curve. Space-time can bend, wrap, or curve depending on the matter inside and the force of gravity acting on it.
Time Dilation
The faster you go, the slower time appears to you. This is a simple explanation for time dilation.
Let’s say you embark on a journey to a nearby star which is about 2.5 light years away from the earth. Picture yourself traveling in a spacecraft at 50% the speed of light. You will reach the star in about five years. You carry our the mission and return back to earth. Now, the total time passed from your perspective will be 10 years. Well! Here’s the twist. When you reach earth, you will notice that more than 15 years have passed. In your time, you would have traveled so fast that the time on earth would appear to move slow. However, in reality, the time on earth will move at its normal pace. The crux of time dilation is that the faster you move through space, the slower your move through time. Therefore, you would appear to be younger than the people on earth.
Space-time manipulation
This topic of discussion is solely a product of science fiction. With current technology, we cannot find a possible way to manipulate space-time. However, a time may come, where we could develop to an extent that time manipulation becomes child’s play. Here are some ways to do it.
Time Machine- With a time machine, you can travel to the past, present, or future. This gives you complete control of time. According to science, you can only travel to the future and not to the past. As traveling to the past would require you to spin the earth anticlockwise, which is an impossible feat.
Traveling faster than the speed of light- This theory boils down to the creation of the universe. The big bang led to the expansion of space and time way beyond the speed of light. If we could figure out how to create another big bang, we could easily manipulate, space, time, and matter.
Wormholes- Wormholes can provide a passage through space-time. But don’t get all high as we are yet to discover them. If so, we can travel through various planes of existence and perhaps visit other galaxies or maybe even a parallel universe.
Space Age 