Thursday, January 15, 2009

Pan Galactic Gargle Blaster

One of my great heroes was the late great Douglas Adams, sometime resident of London and Santa Barbara California; now decaying gracefully in Highgate cemetery along with such luminaries as Karl Marx, Michael Faraday and Herbert Spencer. Despite having the bleak world-view of the militant materialist, Douglas was always able to find the humour in the situation. One of my favourite quotes of his was a remark he made at Digital Biota in Cambridge:

‘There are some oddities in the perspective with which we see the world. The fact that we live at the bottom of a deep gravity well, on the surface of a gas covered planet going around a nuclear fireball 90 million miles away and think this to be normal is obviously some indication of how skewed our perspective tends to be’

But that isn’t even the half of it. According to recent research, right now our tiny pea green speck of a planet and its accompanying solar system is moving at about 600,000 miles per hour rather than the previously estimated 500,000 miles per hour. This additional rotational velocity means that our galaxy’s mass is half-again as great as what had been thought, making the Milky way just about as large as the Andromeda Galaxy. Our particular sprinkling of stars probably has four, not two, spiral arms of gas and dust where stars are forming and we are probably justified in calling ourselves a regional heavyweight.

The residents of the Andromeda galaxy might be looking on jealously, however it looks like with the greater mass, we will collide with them in the near future (2-3 billion years away). This kind of Galaxy merging is fundamental to building up structure in the universe and the process of star creation. In case you are actually worried about this, I should point out that, as with all such collisions, it is unlikely that objects such as stars contained within each galaxy will actually collide. To give you some idea of how diffuse a galaxy actually is, if the sun were scaled to the size of a quarter (or 10p if you prefer) the next closest star would be the equivalent of 475 miles away. If the collision occurs, the galaxies will likely merge into one larger galaxy. As with all mergers there will have to be corporate re branding and possible redundancies. The current intention is to call the new super galaxy ‘Milkomeda’ which sounds a bit too much like a suburban shopping plaza for my taste; but thankfully we have quite a while to come up with a better name; possibly 'The Pan Galactic Gargle Blaster'. There is also a remote possibility our solar system will be ejected from the new galaxy, which will have no adverse effect on it, but will be rather humiliating.

Another mystery which has been solved is the conundrum of how young stars manage to exist in the center of the Milky Way where logically they should be ripped apart by gravitational tides. The explanation is probably that molecular gas and dark matter at the center of our galaxy is denser than previously thought. Greater density means greater gravity, enough to overcome tides from the black hole and hold together sufficiently to form new stars.

We should delight in the fact that we seem to be part of such an elegant and beautiful system. Stephen Hawking once said humanity is nothing but ‘a chemical scum on a moderate-sized planet’, yet despite these lowly origins and the onset of paralysis, he still managed to develop theorems regarding singularities, discover Hawking radiation, father three children and have an extra-marital affair with his nurse.

Not bad considering he is supposed to be the Universe’s equivalent of a yeast infection.

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