Tuesday, August 11, 2009

The beauty and the beast of celestial mechanics

The revolutionary idea of Newton was not finding out there is a force pulling the apple that fell on his head. It was all to obvious. What he found, and made the thinkers of his time so upset -the science was about to be born, it was called natural philosophy back then- was that the same set of rules govern the celestial bodies such as stars and planets -which were perfect and eternal,- and moral bodies such as an apple or humans. He was able to explain the astronomical laws that Kepler derived based on the painstaking observations by Tycho Brahe, with the laws he derived from everyday objects. The world and the skies were never to be seen as different spheres anymore.

This year marks also the 400th anniversary of Galileo's observation of the stars and the planets, and the birth of modern astronomy. Following the path he opened, that is using publicly available observations, we are able to construct a fairly complete model of the history of our universe since -and before- its birth. And just as Newton predicted, we see the beauty and horrors we experience in the everyday life in the skies.

First the beast. The astronomers have found abnormal amounts of glass surrounding a near and new star. It turns out that the glass is the remnants of a collision between two planets in the size of the Moon and Mercury. Here is an animation of how the event might have looked like:



Bad Astronomy has a great explanation of the event.

It is not only planets which collide. Collision of galaxies are not rare occurrences either. In fact the Milky Way is on a collision course with the nearest galaxy, the Andromeda. Thanks to incredible amount of computing power we have, we are able to simulate the collision of galaxies, and compare it with the actual data we obtain from astronomical observations we have, to understand if our understanding of the universe is correct. Here is an astonishing video which visualizes an actual simulation of the collision of two galaxies. It is simply beautiful!

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