Mysteries Of The Cosmos

Yes! We can look into the past! said the physics teacher. There was a variety of reactions that the teacher got from his students. Pratik, undeterred by his teacher's claims was still looking out of the window towards the large field a few hundred meters away from the classroom where a football match was going on. Nikhil was diligently writing down in his notebook every word that the teacher was uttering. Sandeep and Ashish were listening attentively bewildered by the crumbs of science facts that were thrown at them by their teacher. You need not write them down Nikhil. said the teacher. Let us take a detour from our regular lesson and delve into the mysteries of the cosmos.

Allen was a passionate physics teacher and did not miss any opportunity in his classes to spark scientific interest in his young students' minds. He believed that shaping the mind of a school kid ultimately leads to shaping the future. It was the day for the chapter on gravity and after explaining the basics of what gravity is and how everything is affected by this invisible force, Allen next started explaining how big objects like the moon, earth and the sun too are governed by the law of gravity. It was the class just after lunch and it was raining heavily outside. Sensing that his students were in no state to start a new chapter, he decided to deviate a bit from his lesson plan. In no time he was explaining to the students about the origins and the mysteries of the universe.

So as I was saying, we can look into the past and we do it on a daily basis. Just that the scale is different. Every night when you look up at the sky and see those twinkling stars, you are actually looking at the past.

There was silence in the classroom. Nobody could quite grasp what Allen was saying.

Yes, that's true. Stay with me boys let me explain.

So as you all already know, the distance between objects at the cosmic level is measured by light-years. One light-year is the distance that light would travel in one year.

When you see a star twinkling in the night sky, it is, in fact, the light that has been emitted from the star that is reaching you.

Anyone here knows the star that is closest to us? asked Allen.

Ashish quickly responded It is our own sun.

And what is the star closest to us after the sun? Anyone?

It is the Proxima Centauri. and it is 4.24 light-years away from us. said, Allen. So tell me what do you understand from this?

One of the students hesitantly answered It means that the light from this star will take around four years to reach us.

Exactly! Four years to reach us and this is the closest star to the solar system. The stars that you see in the night sky are thousands perhaps millions of light-years away. So what you are seeing is the light that was emitted by the star some million years before. Therefore, I say what you are looking in the night sky is the past of the universe. not the present.

Allen could see the amazement in his students' faces. He remembered his own school days when he would have his mind totally blown sitting in the school library and reading books on cosmology. Just the sheer scale of the universe amazed him and what intrigued him most was that few simple laws of motion put forth by Sir Issac Newton had not only explained nature here on earth but it had virtually answered many cosmic questions. Using these simple laws man had successfully launched rockets, landed on the moon, answered why the moon rotated around the earth and the earth around the sun. Three simple laws and yet the amount of weight it bore was incredible. But there was more mankind was yet to learn about the cosmos. It was questions like this that kept Allen hooked to the science books in his school library.

Sir, what about the future? Can we see the future? asked Roshan.

Allen came out of his thoughts and answered, Well, it's a bit complicated. What you should actually be asking is - Is time travel possible?

Yes sir, like in the movie "Back to the Future". said another student excitedly.

Pointing his fingers towards Roshan, Allen said, Ok. Let us suppose you and Nikhil were born on the same day. Let it be today - 16th of June 2008. So just after birth Nikhil is put into a spacecraft and sent to travel in the universe at almost the speed of light. You then lead on your regular life - study, get a job, get married and maybe after 60 years from today that is in the year 2068, you are planning to retire. Just when you were packing your bags for the retirement vacation, Nikhil's spacecraft lands in your backyard. You quickly go out, ready to welcome him and also take Nikhil along with you on this vacation. To your utter surprise, it is not a 60-year-old Nikhil that steps out of the spacecraft as you might have expected, but instead a young boy maybe around 14 years old. Nikhil is 14 years old just starting to grow a few strands of mustache here and there, and Roshan is 60 years old with no hair and with his beard and mustache already greyed. So 60 years for Roshan was only 14 years for Nikhil.

Everyone started laughing when Allen described Roshan as a 60-year-old man with a bald head.

Allen continued after a short pause, So 14 years after his birth, the year is 2022 for Nikhil and when he arrives back to Earth after his years of Inter-Galactic voyages, ready to tell his travel stories to Roshan, he finds Roshan is already 60 and the year is 2068 here on Earth. Hence, technically Nikhil is already in the future.

But sir, that is practically not possible, right? asked Sandeep with a tone of disbelief in his voice.

Well to answer that question I will have to explain to you the concepts of time dilation and Einstein's Special Theory of Relativity.

Just as Allen was about to explain further the bell rang. Seeing Mrs. Tamang already outside the door waiting for her next class, Allen said with a bit of disappointment, Ok boys we will continue with this topic sometime later. Meanwhile, you can take hold of a book in the library and read more about it.

Allen rubbed the diagram of an apple that he had drawn on the board, picked up his book from the table and left from the classroom.