If you talk about future physics, then time travel is amongst the new frontiers scientists are trying to explore, and probably win. However, one of the main hurdles in time travel is that we have to acquire a speed more than the speed of light! Enthralling as it apparently seems, it is practically next to impossible. So, if we can't travel at this phenomenal speed, is time travel really possible? Well, hopefully, in the future!
Physicists all across the globe are searching for one unified theory, that one special theory which connects everything. Aerospace engineers are planning to design spacecraft so that mankind could travel to stars! But to make any of this possible, a way to break the speed of light needs to be found.
Speed of Light: An Overview
It was Albert Einstein's Theory of Relativity that established that the speed of light is the maximum speed any particle can attain on this universe! Whether you travel in the world's fastest planes or a combination of hundreds of planes, there is nothing in this universe that can attain a speed more than that of light. It's the end, the ultimate limit for speed!
When light travels from one medium to another, its speed changes. Students recall the concepts of 'refractive index', that plays a major role in increasing or decreasing the speed of light in a specific medium. In a vacuum, however, light, and numerous other electromagnetic waves, like x-rays, microwaves, radio waves, and all waves in the visible spectrum, viz., VIBGYOR, travel with a speed equal to that of light.
The speed of light in vacuum is 299,792,458 m/s. Expressed in mph and kph this works out to be 670,616,629.38 and 1,079,252,848.8 respectively. Quite difficult to remember, isn't it? Those who have studied physics must be able to recall that this is not what they learned. Yes, you're correct. This number is simplified for calculation purposes and it is represented in standard forms. So, the most popular form of expression in physics is:
|Speed of Light: 3.00 x 108m/s|
It is expressed by the alphabet 'c' and it is a standard symbol in modern physics. Again, the greatest of the great, Einstein, immortalized the speed of light by giving us the formula, E = mc2
At 300,000 kilometers per second, the speed of light is just instantaneous on Earth. After all, 300,000 km is an amazingly long distance to travel to in the solar system, but on Earth it is nothing. To amaze you further, even with such a tremendous speed, light takes almost 8.3 minutes to travel from the Sun to Earth!
On earth, this may seem to be fast, when we talk about the emptiness of space, it is a meager quantity! So, if your friends want to know how fast light travels, do tell them that its speed is about a million times more than any F1 car or supersonic jet!