Saturday, December 9, 2006

24)Basics on the vast distances and sizes in Astronomy

Regarding my posts on Astronomy and the vast sizes of galaxies and vast distances between galaxies and between the earth and such galaxies, I think it would be prudent to post a few explanatory numbers so people can have some idea of the vastness of space relative to distances on earth.

I have read that the furthest distance between two points on the earth is between Vancouver, Canada and Cape Town, South Africa( about 13-14 thousand kilometers).

Because of the vastness of space, a convenient way to give very large distances is in terms of the light travel time.

The speed of light is 300,000 kilometers per second(km/s). It is the largest possible speed with which information can travel through space. Hence light travelling from the moon 384,000 km away from the earth takes 1.3 seconds to reach us. We say that the moon is "1.3 light seconds away". This led to the noticeable delay in the responses of lunar astronauts to(radio transmitted) questions from people on earth.

The sun is 150 million(150,000,000) km from earth. It takes light 500seconds(8.3 minutes) to reach the earth from the sun. We therefore say that the sun is "8.3 light minutes away" away from earth. If the sun abruptly stopped shining, we would not know it for 8.3 minutes because the emitted light is already on its way!

A light year is the distance light travels in one year. By the above-mentioned speed of light, one light year represents a distance of 10 trillion km( a one with 13 zeros in front of it!).

The nearest star in our own galaxy to our solar sytem(our sun and all its planets) is called Proxima Centauri and it is 4.3 light years away(or 4.3 time 10 trillion= 43 trillion km away from the earth or 43 with 12 zeroes in front of it). The nearest large collection of stars(galaxy) to the earth, the Andromeda galaxy, is over 2 million light years away(that is 2 million multiplied by a one with 13 zeroes in front of it to give the number of kilometers away from earth, or 2 with 19 zeroes in front of it). The Andromeda galaxy is also 100,000 light years in diameter, ie, you would have to travel 100,000 multiplied by a one with 13 zeroes in front of it= a one with 18 zeroes in front of, kilometers, just to go from one end of this galaxy to the other!!!

The picture from the NASA website of two galaxies colliding with each other at this very moment shows them to be 140 million light years away from us.

There is only one response to the incomprehensible distances within and the vastness of space: Allahu-Akbar!

easynash

Islam, eminently logical, placing the greatest emphasis on knowledge, purports to understand God's creation:Aga Khan 4.
The God of the Quran is the One whose Ayats(Signs) are the Universe in which we live, move and have our being:Aga Khan 3