Astronomers would tell us that looking into a star on a star-studded night is the same as if we are looking back in time. Based on our common intuition of time, this might appear so quizzical that others may not bother to consider about the validity of this scientific fact. Today, it ranks among one of the established truths of science. How did the old science of astronomy then arrive at such a wonderful scientific conclusion?
The notion of this seeming similarity all started when astronomers discovered that light did not travel in such infinite speed after all, in contrast to what was generally believed prior to the pioneering works of Olaus Roemer and eventually the historic experimental triumph of Albert Michelson at measuring the speed of light. Michelson, one of the greatest American experimental physicists found that light covered a distance of 186,000 miles a second. And as far as modern physics is concern, it is the limiting speed in the universe but absolutely definite, meaning it would take time for light to take a distance, the truth of which may run counter to our thinking because our real world experiences are limited to offer us situations that only allow light to travel at very short distances, resulting to the seeming insignificance of time lapses as light travels from one point to another.
But as the distance for light to travel significantly increases, the time it would take to travel becomes largely significant. For one, sunlight reaches the earth eight (8) minutes after leaving the surface of the sun. It maybe too short of a time for a 93,000,000 miles earth-sun separation, but cosmologically speaking, other stars in our galaxy itself are millions of light years away from earth. Thus it could take a couple of tens or hundreds and even thousands of years for light from a distant star to reach the earth. On this ground, science can very well conclude that starlight that we see at night actually left the star surface tens or thousands of years ago. What we see is actually an event that occurred many years past. Hence, stargazing hobbyists are actually like travelers back in time.
