Extremophiles and Life Beyond Earth

by AMNH on


Research about organisms that can weather Earth’s harshest environments has broadened ideas of where living things can thrive. On Sunday, March 11, the Museum’s 2012 Milstein Science Series kicks off with Extremophiles: Life in Extreme Environments, an exploration of how such organisms survive and what studying Earth’s extremophiles could mean for the search for extraterrestrial life. Seth Shostak, one of the guest speakers at the March 11 program, is a senior astronomer at the SETI Institute and researches whether life—from the intelligent to the extreme—could exist elsewhere in the universe. Below, Shostak answers a few questions about extremophiles and the search beyond life as we know it.

How does the study of life in extreme environments on Earth inform our search for life beyond our planet?

Seth Shostak: When we think about life beyond Earth, we usually think of life on a planet that’s like Earth because we know life can work with liquid oceans, nice temperatures, lots of oxygen, and a thick atmosphere. But by studying extremophiles, we find that life can survive in environments that are not good enough for us, but plenty good for them. The bottoms of oceans, temperatures above boiling, very cold regions—all these are kinds of environments we’d find on lots of planets that might not be the place to build condos but might be festooned with life.

What types of extremophiles are the most important for the search for extraterrestrial life?

Shostak: You could say penguins are extremophiles, but the main ones being studied are bacteria-sized. Ones that we rightly focus on are the extremophiles in the deep-sea vents of the ocean where sunlight doesn’t reach. That’s an interesting locale because it might be the kind of thing you’d find on some moons of Jupiter, like at the bottom of Europa’s ocean, which is pitch dark with ice above it.

Part of your research at the SETI Institute involves using radio telescopes to search for intelligent life. What kind of signals are you looking for?

We look for the type of signals that transmitters make. Most people think we are looking for messages or patterns in signals, but that’s what they do in the movies. In reality, we look for signals that are limited to one spot on the radio dial. Nature makes a lot of radio noise, from lightning bolts, the Sun, quasars, and pulsars, but that static is everywhere you tune. And so we look for the kind of signals that we know transmitters can make and nature cannot.

Can you describe the new citizen science program SETI launched to decipher these signals?

In some parts of the radio spectrum, there’s so much interference due to human activities that our computer programs get confused. But eyes are pretty good at looking at displays and picking out patterns, so we’ve asked citizens to look at some of these data to give us their opinion. And if many think, hey, there’s something here, we’ll have our antennae go back and look.

What are some things we need to understand better about the home planet in order to understand the potential for life beyond it?

Beyond extremophiles, another challenge is to understand how life got started on Earth, because we don’t know that yet. If we took all the life on Earth and threw it on Mars, some things would still be alive two years later. The question is whether life could have ever gotten started on Mars.

While giving a talk at a conference, I said sending celebrities to space could get people interested and showed a cover of People magazine with Justin Bieber on the front. If you send Bieber to space, some people will develop some interest, and if you have more interest, you’ll eventually have more people, which means it will be less expensive and all sorts of technical developments will follow. Look around at an airport, and people are reading People magazine, not the Journal of Geophysical Research. People are interested in people.