Time Travel is one of the most exotic topics on fire in the scientific community, and why shouldn’t it be? The thought that you could go back in time and re-live the happy moments or stop yourself from getting into an embarrassing situation, or travel to the future to know what it has in store for you, is just exciting. There are scientists who support the ‘theoretical possibility’ of time travel and some who don’t, but this is a debate than can and will probably continue for ages. BUT. What if I told you we actually do experience time travel? Not in the conventional way of sitting inside an enclosed pod surrounded by electronic circuits, or a DeLorean car modified to travel in time using a Mr. Fusion Home Energy Reactor (YES! A Back To The Future series fan here!), but more like the past reaching out to you, while you are still right where you physically are. Hold on! Don’t tag me crazy before you hear me out.
The kind of time travel I am talking about might not sound so adventurous at first, but stay with me, and think about it. I am talking about Star-gazing, and related stuff like Observational Astronomy. We have all spent some sleepless nights, sitting under a clear night sky with stars twinkling all over, and pondered on some deep thoughts, but what most of us fail to notice is that the little twinkling balls of fire we are seeing are actually the ‘images’ of the real objects thousands to million years old! Okay let me help you understand. We know that we see an object when the light reflected/released by it enters our eyes. Now, though light has a crazy high-speed ( 29,00,00,000 meters per second), the maximum that the laws of physics allow, even then it is a finite value, and not infinite. So, picture a car, now this car is travelling from point A to B which are quite far from each other, and you are there at point B. Now until and unless that car reaches point B, you won’t know what that car actually looks like, its color and other related information. This is exactly the case with light, despite its speed its takes a certain amount of time to reach us over large distances. Thus, it is the past of the future you are admiring.
This is actually the case with everyday objects but light reaches so fast from them to us that we cannot experience the delay. But, for astronomical objects like stars, galaxies and planets it is actually the light from the past. You are time travelling in past! Say for example our sun, the light from it takes around 8 minutes to reach us, and so the sun you see is actually what it looked like 8 minutes ago. So, if the sun was to go off instantly, you would know about it around 8 minutes later, when the last light emitted by it reaches you! Think about it. What a crazy thing it is! The stars you find solace on those beautiful nights might not be even there, for all you know some of them might be dead right now, but depending on their distance, the last of the lights from the star hasn’t reached us yet, and we wouldn’t know until they do. Suppose if the nearest star Alpha Centauri that is 4.3 light years away(i.e. light from it takes 4.3 years to reach us) was to burst into a supernova right now, we would see the supernova after 4.3 years.
When you read about scientists finding about an event that happened billion years ago (like the collision of black holes 1.3 billion years ago that was seen recently), or studying a galaxy to know what happened in the early Universe, and you wonder how can they see an event that happened billion years ago or see what the early Universe looked like, THIS IS HOW. Similarly, if an alien, more than 65 million light years away was to look at our home through a telescope, it would see dinosaurs and not us, because that is when dinosaurs roamed the planet. Theoretically, if you could fix a mirror 32.5 million light years away and look into it, you too could see them.
The outer space is a big picture, or to be precise a video recording of the past! We are glaring back at our past, when we look at galaxies we see how we came into existence, these pictures help us know our origins better. I don’t know about you, but I have spent countless nights thinking about this, and the more I think, the crazier it gets, and the more in love with these thoughts I fall in. Universe is full of wonders, which may seem quite normal or boring at first sometimes, but once you ponder about it honestly, you are introduced to ideas and thoughts that will blow your mind and excite you a lot! The world around you is much more complicated, weird and yet beautiful than you think. So, the next time you look at that star, just think about the vastness of history you are looking at, think about what I mentioned here, what the star perhaps looks like right now? Is it still there? What secret does it hold for us in the future? I assure you, you will be surprised by the rush of emotions and thoughts you have.
The next time when someone says that time travel isn’t possible, make them look at the night sky. Don’t just stare, notice and think. Happy Reading!
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-The Cosmogasmic Person