Will We Ever Colonize Mars? (Op-Ed)
by
Paul Sutter, Astrophysicist | September 28, 2015 03:13pm ET
Paul Sutter is a research fellow at the Astronomical Observatory of Trieste and visiting scholar at the Ohio State University's Center for Cosmology and Astro-Particle Physics (
CCAPP). Sutter is also host of the podcasts
Ask a Spaceman and
RealSpace, and the YouTube series
Space In Your Face. He contributed this article to
Space.com's Expert Voices: Op-Ed & Insights.
Ah, Mars. The place that dreams are made of. As long as those dreams involve a poisonous, tenuous atmosphere, inhospitable cold and lots and lots of red. Still, people seem to want to go there. But will we ever make it?
"Yes," if you ask Elon Musk. I agree, but it probably won't be as easy as you might think, even if you think it's going to be really really hard.
Gravity doesn't know when to give up
What's the problem? Pick up the nearest object and throw it. I don't care if there are people around you. Do it. This is an experiment. This is science. Note how far the object goes before it hits the ground. Now pick it up and throw it harder. It went further, didn't it?
Part of the reason you didn't throw it as far as your ego thought you would was air resistance. Plowing through the atmosphere like a bull in a molecular china shop, the object quickly loses speed. But the actual "hitting the ground” part is due to gravity. If you took away all the air, your thrown object would still eventually hit the ground.
In an airless world, no matter how hard you throw the object, it will reach the ground in the same amount of time. That's because gravity only works in the "down" direction, not the "over" direction, so for all gravity cares, you might as well have just lazily dropped it. But the harder you throw it, the more speed it will have, and the farther it will go before inevitably hitting the ground.
Or maybe not so inevitably. Imagine throwing something so hard that in the few seconds before it hits the ground, it reached the other side of a house. Or maybe a street. Throw it harder and you could get it across town. Across the country. Even faster: across an ocean.
Imagine throwing it so fast that by the time gravity gets around to doing its thing, the Earth has curved away from it. Gravity keeps on tugging at the object, but it frustratingly keeps missing the ground. ...
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