We are going to perform a Gedanken experiment, so saddle up and hold tight as we travel faster than light to understand a simple truth about life and death.
Spring of 1995, I was at the planetarium attending a Saturday lecture by Prof. Shylaja. She was talking about light year as a unit of distance and that all the objects we see in the night sky are either dead or very old! They are not really what they appear to be. This completely surprised me beyond belief.
Think about it, light takes 510 seconds to reach the earth from the moment it leaves the surface of the sun. If we calculate the time taken by a photon (Particle of Light) emitted at the centre of the sun to reach its surface, there is a huge problem here. Any guesses?
Physics tells us that light travelling at 3,00,000 kilometre per second takes nearly 1.2 million years on an average to travel from the centre of the sun to its surface even though the distance is only 7,00,000 km. (This is called the random walk problem in physics)
Stay with me. This would mean that if the sun were to stop emitting light at the centre today (Sun were to die), we don’t need to worry about it for another 1.2 million years. Baffled? Let us look at another situation. Consider a star 60 million light years (MLy) away from the earth i.e., light takes 60 million years to reach us after leaving this star. Suppose, there are aliens out there and they are as intelligent as we are (if we really are!) then how would we appear to them?
This star is 60 MLy away from us, the civilization that is there would have received light from the sun that left 60 million years ago and they would be looking at the solar system that is 60 million years younger than it is today. So, for them the dinosaurs would be still alive.
We can extend this thought to the next level; let us by some means go faster than light to reach this amazing star, what would we see? Astronomers today are spending billions of dollars on searching for life elsewhere in the universe. Indeed a great human achievement, but isn’t it surprising that we are searching for life everywhere in the universe near and far without really bothering to respect and love the ones that are around us in real-time? Because, even if we find life elsewhere, it only means that the life existed there and we have no clue on its current status.
Anyway, let me tell you this secret, if we can travel faster than light and go to a star 50 light years away from us and then take a look at the earth, we will be able to see our parents in their infancy. But remember we will also see our grandparents who might be dead here on earth, but will be alive when seen from there. The only catch is that we may detect their presence but will not be able to interact with them.
Whatever is the consequence of my journey faster than light, my grandfather is still alive to some civilization that is far away from here! Isn’t this a solace that we will still be alive to someone somewhere out there? It is just a matter of time and space.
– Dr. Sriraghavan S M
President, Education and Collaborations