*SciShow intro*
You are full of microbes right now. Seriously, they're everywhere! Luckily, they're mostly harmless, but the fact that they're pretty much everywhere on Earth means that when we go to other places, say the Moon, we bring them with us.
So, are there colonies of bacteria on the Moon?
(0:19)
As far as we know, nothing can survive the cold, near-vacuum of space for that long. Though at one point it did seem possible. On November 19, 1969, Apollo astronauts Pete Conrad and Alan Bean landed on the Moon. 
(0:32)
They touched down just over 100 meters from Surveyor 3, an unmanned lander that was sitting on the lunar surface for two and a half years.
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So the guys strolled over, nabbed Surveyor 3's camera, and brought it home in a sterile container. But back on Earth, when scientists analyzed the camera in a sterile room, they found about a hundred specimens of streptococcus mitis living inside. That's a bacterium often found in the human mouth.
(0:55)
It seemed like a small colony had somehow survived two and a half years on the Moon. But there were rumors that there were all sorts of problems with the analysis. 
(1:03)
Maybe the camera was brought back in a breathable nylon bag? Or maybe the sterile examination tools they used had been left on unsterile surfaces? Or perhaps the researchers weren't wearing the proper clothing? 
So did we give the moon cooties, or just the camera, once it was back on Earth?
(1:18)
Probably just the camera. In 2011, NASA researcher dug up old footage of the test, which showed a bunch of contamination issues that would never fly in a lab today. The scientists, for instance, were wearing regular scrub style shirts that would have let bacteria travel inside their clothes to the camera.
As opposed to these days, when people doing that kind of research usually look more like this.
(1:42)
Which, in a way, is good news. It means that our current understanding of how and where things can survive is still pretty accurate.
(1:47)
Microbes here on Earth can survive some pretty amazing stuff. There are bacteria that can thrive under the extreme pressure in deep sea, the extreme cold of permafrost, and even in space, but only for a little while.
(1:59)
In 2011, an astrobiologist in Argentina found that two of the world's hardiest bacteria could survive for three hours in a vacuum while being blasted with the kind of UV radiation you'd get on Jupiter's moon Europa. But that's only three hours, and with two of the world's toughest bacteria.
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Tiny, adorable animals called tardigrades can do a little better, and last for at least 10 days in space. Though they shrivel up and die...and have to be revived once conditions are a little more friendly.
(2:26)
Any germs on the Moon would have to survive the 200 degree days and the negative 200 degree nights, the near vacuum of the Moon's surface, plus intense UV radiation from the sun, not to mention no access to water or nutrients. So even if we did leave some microbes up there, they're almost definitely all dead by now. Rest in peace, little microbes.
(2:46)
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(3:01)
*SciShow end credits*