As Far As We Can See

  

Train journeys provide ample opportunity for good conversations, either be it in a long journey or a short one. While travelling by train I could see complete strangers getting acquainted and involving in many interesting conversations with topics ranging from cinema, philosophy & politics, mostly the later & you unwillingly or unconsciously become a listener.

        In year 1999, I was travelling by a passenger train to Vijayawada from Tenali along with 3 of my collage friends to attend a training session. To make the 50 min journey interesting & to make us forget that we didn’t get any seats and were standing in the aisle, I put a question to my friends.

   “ How far can you see?”, I asked generally. First friend said immediately “1 Km, I can see the bus coming into the town from the highway”.

    Second friend said, “ I can see the hill from the roof of my house which is 5km away”.

Third friend was of a philosophical nature & said, “We can see as far as we can imagine”. Seeing that this could put the conversation into a different tack, I modified the question and made it more technical & specific.

    “ How many kms can an unaided human eye can see ?”.

After a few moments of thinking, the first friend replied hesitantly, “20 kilometers?”

   My idea of luring them into conversation was to provide a bigger picture & not to trouble or ridicule them. Before I could reply, my philosophical friend replied,  but this time thankfully in a complete factual statement.

     “The distance you can see is directly proportional to the size of the object you are looking at, simple”. Yes he was absolutely right and the answer was actually quite simple.

     I said, “ Yes, and what you said in the beginning is also true in one aspect. To see the bigger picture we need to increase our imagination & take into account the objects beyond our world”.

    “ Forget about the bus & the hill. We can see the moon right? Its about 3,56,400 Km away & our eyes can see it”.

     They caught on & the second friend said, “ We see Sun every single day, why didn't I think of that before?, how far is it?”

" 14,96,69180 Km away”, I replied.

 “We see so many stars in the night sky, some of them very very far away”, the first friend said.

 

        I said, “The nearest star to us is alpha centauri which is visible to unaided eye and is 4.21 Light years away”.

        The not so philosophical any more friend replied, “ that is 4.21 x 3,00,000 x 60 x 60 x 24 x 365 km, (which is 39829968000000 Km).. Wow, we can see that far?, and that’s just the closest star to us. I wonder which is the farthest object visible to the unaided eye then?”

     “ That’s probably how I should have put the question in the first place”. I said apologetically, “But it would have ruined the curiosity & fun factor of the conversation”.

    First friend said, “ I wonder if it would be a star which is the farthest object visible to us,  Could it just be possible that any other galaxy than our own beloved Milky Way is also visible ?”

    This is what I wanted to come to when I put the question, “ You are right friend. The farthest object visible to the unaided eye is the Triangulam Galaxy. Which is a member of the local neighborhood of galaxies, of which ours & the famous Andromeda Galaxy also belong. Triangulam Galaxy is believed by astronomers to be an astounding 3.5 Million light years away. And during clear nights away from city lights this galaxy is visible to the unaided eye as a fairly faint & small smudge in the sky”.

     They were astounded, as much as I was when I found out about this fact.

     Second friend said,” That would mean it is 3500000 x 300000 x 60 x 60 x 24 x 365 km away ( which is 33112800000000000000 Km)  & our unaided eye can see it… wow.. “. He continued, “ Do you realize that it means we are looking 3.5 million years into the past when we look at it, as the light would take that much time to reach us?”. 

First friend said,” yes, it seems that way isn’t it? As far as we can see.”

         The look on my third friend told me that, he had finished his quota of facts and was desperate to quote philosophically, when I realized that as we reached a conclusion to our conversation, fortunately we had also concluded our comparatively infinitely small journey of 34 km.

        The train had reached Vijayawada Station. We got down & mingled into the crowd moving to wards the exit. 

Ravindra

Delhi

23-12-2012 1600 SUN