:
|
Isn't it debatable whether our bacteria would even effect any autochthonic life on Europa any way? Like, the whole premise to us surviving War of the Worlds is fallible.
|
The point is that if we find bacteria on Mars, we want to know that it actually is from Mars and not brought there by us. There's a whole department at NASA focused on this. It's a surprisingly difficult problem.
For example, NASA has a pretty good idea where on Mars life is more likely to exist - regions with large amounts of water ice are a the best bet. And yet, the Curiosity rover was sent elsewhere. This is because it has a radioactive power source; if it crash landed, it could melt the ice and provide a nice warm area for Earth bacteria to multiply. Also, Curiosity has a robotic arm that can pick up one of a number of drill bits for drilling rock. They were treated to extreme conditions - cleaned with bleach, high temperatures, radioactivity - to kill any bacteria that might have been on them. And then one bright engineer opened the sealed box, took out one of the bits and attached it to the arm before takeoff. Now NASA won't let Curiosity go near
any potentially life-bearing rock, because we simply can't know whether those bits brought anything along with them from Earth.
Water on Mars
