Sunita Williams will run Boston Marathon in space tethered to bungee harness. To run the earth equivalent of 26.2 miles, she will run 210 miles in space void of gravity.I don't know the funda of how the 26.2 miles became 210 miles, nor do I know how she will complete it in 43.28 seconds. But I do know that she completed Houston Marathon under 3:30 is qualified to run the Boston Marathon if she is on earth and I can only dream of it.
Good Luck Suni & Go Girl
(via kk)
Consider the following experiment: let's say that you walk across your house and I measure your speed. We must remember that this is only a relative speed - this is your speed with respect to the floor of the house. For instance, if our house is actually in a fast train and we ask another scientist standing on the ground outside of the train to measure your speed, he/she will say that you are moving with a speed much larger than what we had measured. The reason we measure different speeds is that we are in different reference frames. You and I are measuring speed with respect to the floor of the train, and the scientist that is outside is measuring speed with respect to the surface of the Earth. These techniques will give different answers.
ReplyDeleteWhich is the "right" answer? In fact, they are both right. There is no one correct frame of reference, because the laws of physics are the same in all reference frames that have a constant speed and direction of motion. This idea is called the "principle of relativity", and it was first proposed by Galileo Galilei in 1632. Since then, this idea has been tested experimentally and it is now widely believed to be true.
So what is the speed of the Earth, then? Well, with respect to me, the speed of the Earth is zero, since I'm sitting at my desk! However, with respect to the Sun, the Earth is moving in an orbit at a speed of 18.5 miles per second, which is quite fast. The Earth has an even faster speed with respect to the center of our galaxy, since Solar System itself is moving relative to the center of our galaxy with a speed of 155 miles per second.
If the Earth's speed with respect to the Sun were to suddenly become zero, then we would be in big trouble because of the gravitational force that attracts these objects to each other. It is precisely that large relative speed of 18.5 miles per second that keeps the Earth from falling into the Sun and colliding with it. In the absence of this orbital speed, the Earth and the Sun would merge, and all life on Earth would cease to exist. Similarly, if our galaxy suddenly stopped rotating, it would collapse together for this same reason - the nonzero speed of orbits keeps our galaxy spread out like it is.
Interesting, is not it?
Raman
Raman
ReplyDeleteWonderful.. Thanks for this.. I learnt something new today.. I kind of knew about 'relative speed' and stuff and this puts it in context..