Whilst we define time as a theory, and declare the past inaccessible, we have a tiny display of what the past is every single day. I was aware of this for a while, but never really cared to ponder about until my astronomy professor asked it during the first day of classes. It might be quite obvious too, and you most likely know it as well: “When you look up to the sky at night and see the stars, what are you really seeing?” the room went silence for a few seconds, and the professor glanced around the room to look for an answer. Taken there had been a high amount of participation throughout the whole lecture, we all were surprised no one knew the answer. However, it all made sense after a quick thought. “The past,” I said softly.
Since light takes years to travel in outer space and stars are hundreds, thousands, if not millions of light years away from us, what we see up in the sky at night is not the star at the precise moment, but is actually the star’s past. For all we know, that star might have crashed into a supernova already, and no longer exist. However, since it is hundreds of light years away, we will not see that information until those hundreds of years pass. Think of light as a huge beam of information. It is currently hitting us, so we are looking at a star’s past. However, we do not know if it is still alive, changed color, became bigger, or suffered any kind of modification. Spooky, huh?
Now, to step it even further, imagine we placed a gigantic, planetary mirror 50 light years away from earth right now (if technology permits, of course). Then, take a telescope strong enough (technology permitting, again) from the earth and take a glance to it. What would we see in the mirror’s reflection? The earth, but not quite our time era. Instead, we would be looking at steam devices, powder kegs and rifles, fancy uniforms, and a mostly-rural world. In fact, we would be looking 100 years into the past. The light coming from earth also has its own unique ‘beam of information’ that contains our past. Is that not amazing?
It is frightening to think that, if technology ever achieves such greatness, we would be allowed to look into the past? Think about all the secrets, theories, and thoughts that would no longer be a mystery, but rather would become facts. Then if we applied the same concept further in, we could discover and endless amount of facts from the strangeness of the cosmos. The view from earth into a night sky is certainly pretty and amazing, but if science is applied to it, it is even more astonishing.
