How do we know that the big bang happened?
When you notice something out of the ordinary, you apply your mind to it. You consider all the possibilities that made it extraordinary. Then you choose the probability that stands tall against all the others. Difficult as it might be to accept, what we see in the sky is Time on a huge scale. The scale you use for this purpose is the speed of light per second – nearly 300,000 kilometers per second – which is 9,460,528,000,000 km per hour! . By that reckoning, the Sun you see at mid-noon is 8. minutes old. The twilight suns are a little older. Mars is only 30 seconds away. The nearest galaxy is 25,000 years away, but the nearest spiral galaxy, somewhat similar to our own Milky Way, is 2 million years away. The Hubble telescope placed in space by Nasa lets us see into much deeper in space, distance of several trillion light years.. Thus, a modern telescope in the sky, not obstructed by terrestrial obstructions like buildings, lamp posts and mountains can show you time as well as spacial distance, because the sky is a timekeeper that displays the history of our universe, measured in time’s huge perceivable unit – the lightyears.
