How Many Microbes Live on Earth? | Peter Girguis
About The Episode
Sorry, Beyoncé, it turns out microbes rule the world. Microbiologist Peter Girguis explains how to conceptualize just how many microbes are on Earth… and how understanding this helps us look for life on other worlds.
For more, check out the extended interview with Peter Girguis.
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PETER: Microbes really rule this planet. I mean, they run the planet and there are about 10 to the 27th microbes on earth. And one of my favorite things to tell students, and this is legit true, is if you took those microbes, each about a micron in size, and you strung them end-on-end, like pearls on a necklace, they stretch 105,000 light years.
HAKEEM: What?
PETER: Right.
HAKEEM: Holy cow.
PETER: Right. So, right?
HAKEEM: Go ahead.
PETER: That's across our Milky Way. That crosses the galaxy, right? So when I think of big numbers, I don't think of astronomical numbers anymore. I think of microbial numbers, and it's a reminder that there's a lot of them here. And with that being said, they work together to run the planet. And so if we want to think about life on say, Mars or Europa or Titan or in some of this, you look to Earth first and say, "What are the fundamentals here? What is it that these microbes do and how do they make a living?" And that helps us think about what to look for on those other planetary bodies.
HAKEEM: Man, as a scientist, I'm skeptical. And when you first said microbes run the world, I immediately thought, not according to Beyonce, she's like Girls, we run the world.
PETER: In addition to Beyonce, microbes run the world.
HAKEEM: All right, all right.