In previous articles we have discussed the beauty of Einstein’s Relativity. His two theories; Special and General Relativity revealed the most creative workings of nature. In Special Relativity we have discussed about time-dilation, speed of light, length contraction and energy-mass equivalence. But all these phenomena can be noticed only if we acquire atleast 1% speed of light. The fastest man-made object is space-craft Helios at the speed of 97.222 m/s; which is way far away from light’s speed of 300000000 m/s. So it’s difficult for us to notice any significance of Special Relativity. What about General theory of relativity?
General Relativity predicts that mass distorts Space. The presence of mass actually curves the fabric of cosmos and thus affects the motion of objects. For e.g. from the above figure the red line indicates the actual path of light from a distant star after being deflected by the planet’s gravity. The violet ray of light is the observer’s perception! Light from actual position of star initially posses a straight line motion but gets curved because the planet is curving the space. If the observer is unaware of General Relativity, he would perceive the position of star at wrong coordinates (virtual position of star). This phenomenon is called as Gravitational Lensing.
General Relativity also says that Space and Time are interwoven into themselves. One cannot simply make them or tear them apart. So if mass distorts or say, curves space; it must also curve the time. What does this mean? If there’s a planet with certain mass, it curves time-coordinates to cause abnormal behaviour of time itself. If we set out to orbit this planet the time spent for us would vary as compared to time spent on earth. Suppose that if we set out on a long journey to orbit around a Black Hole, the time would almost stop for us as compared to time on earth! This is because a Black Hole has so immense mass and density that it literally curves the Space-time fabric to infinity. Since the time is distorted to infinity, it will make time to flow very very slowly. It’s somewhat close to a fiction of ‘TIME TRAVEL’. If you perform the above mentioned experiment, you would actually travel to future, and hence you would be much younger as compared to your friends, colleagues or may be as compared to your son and daughter! To become young, no one would deny it but you have to pay a cost for it. The known Black Hole is V4641 Sagittarri which is 1600 light years away from us. To get there even light takes 1600 years and hence with the existing technology it’s impossible for an individual to go there! Pretty bad for all of us.