Approximately 4.5 billion years ago, a mere 30-50 million years after our solar system started to coalesce, our young planet was struck by Mars-sized object named Theia, the Titan mother of Selene, Greek goddess of the Moon*. The result, after a mind-bogglingly violent collision**, was a slow accretion of our Moon out of the wreckage left in orbit around the Earth, or rather, the “new” Earth.
Then, for quite some time, not much happened. Despite its unusually large size compared to its parent, the Moon didn’t have sufficient mass to hold an atmosphere, so it just had to watch the Earth’s form and evolve. It also was much less massive than its neighbor, so even though it started out happily spinning at a spritely clip, Earth’s gravitational field eventually forced it to match its rotation period to the time it took to orbit the Earth. For this reason, millions of years passed with the same face of the Moon always staring at Earth, though with different bits of it lit by the Sun depending on when one looked. For a long time, there was no one around to observe this oddity, and then after there was, thousands of years passed as humans tried to explain this eerily beautiful phenomenon. Once we figured that out, it took only one more geological blink-of-an-eye before someone, let me call them Chris***, had the idea of visiting someday.
I like to think that Chris wanted to go there for the sheer wonder of it, rather than wanting to plunder the Moon’s famous green cheese reserves or some such thing. This isn’t completely wishful thinking on my part. After all, at the time Chris was having this thought, flying through our own atmosphere was the exclusive pervue of certain wildlife. The idea that a human could not only fly but make it to the Moon was such a leap that you would think only whimsy could bring it into the mind. It is a bit sad that whimsy was far from the primary motivation that set the mission of the Apollo program, though admittedly a whim is scant reason to spend $170 billion (in ‘modern’ dollars). Still, at its heart, before Apollo became fraught with strategic and material concerns, before it become a symbol of democracy’s triumph over the Soviet system, before Apollo even became Apollo…there was the thought of “Well, why don’t we just go there and find out?”.
For the Apollo Program to ultimately succeed, it needed people with this kind of thought and with the seriousness of mind that could make it a reality, and it got them. One of the most famous, Mr. Neil Armstrong, died on August 25th, 2012, some 43 years after setting his feet on the Moon and some 4.5 billion years after the Moon was spectacularly blasted into being. I cannot do credit to the man and the myth that was Neil Armstrong****. Suffice to say that I think he is nearly unique among humanity’s modern icons and will likely continue to be even after we someday place a person on Mars or beyond. Those nerves of steel. That blood of ice. That first step on a celestial body other than our own. For me, just thinking about it gives a chill and then an exhilirating sense of freedom to imagine what might be possible.
I acknowledge that losing oneself in such imaginings without corresponding action is probably harmful, maybe just a little, maybe quite a bit. …and to concentrate on what might be possible, is perhaps to lose sight of what is possible, right now, on Earth. To put it mildly, humanity has its problems. I’m sympathetic to this line of reasoning, but I would argue that things like the space program need not directly come at the expense of doing good here on Earth and can do good in ways that are difficult to foresee. I think the sentiment is expressed beautifully by a quote our neighbor to the north contributed to a silicon disk left by Apollo 11 on the Moon’s Sea of Tranquility.
Man has reached out and touched the tranquil moon. Puisse ce haut fait permettre a l’homme de redecouvrir la terre et d’y trouver la paix. (May that high accomplishment allow man to rediscover the Earth and find peace there.)
-Pierre Elliot Trudeau, Prime Minister of Canada
* There you are, evidence that scientists don’t name all ‘new’ astronomical objects things like “NGC 2770”, which is a pretty boring name for a galaxy that has produced lots of supernovae recently and is 88 million light years (8.36 x 10^20 kilometers) away.
** To get some idea, take the Barringer crater in Arizona as a reference. It’s over a kilometer wide, 170 meters deep, and was created 50,000 years ago by a meteorite traveling >10 kilometers per second with a mass somewhere around 500 million kilograms (think, mass of a filled oil tanker). Theia was probably traveling slower, just a couple kilometers per second, but had mass about 1,000,000,000,000,000 times greater. Boom.
*** Best to hedge here and give the person a gender-neutral name in case, um, risen-from-the-grave-Chris ever shows up to claim credit.
**** For a good obituary, read here.
Constraining Complexity 