Lipp's Lab:

Integrative Biology professor Jere Lipps studies evolution, but he doesn't limit himself to planet Earth: "I'm interested how life evolves, and the environmental context in which that happens, on any planet anywhere." Among other things, Lipps studies how life could evolve on Europa, a moon of Jupiter.

Jupiter has three ice-covered moons: Ganymede, Callisto and Europa. The latter is the best candidate for life, because it has a liquid ocean and slushy water under its icy crust. And the ice-water interface, as it turns out, is a good place for life to evolve.

When water freezes into ice, it forms a crystal structure that is pure H2O. Any other particles are "squeezed out of the crystal lattice of the ice," says Lipps. These particles and nutrients become concentrated in liquid channels that weave through the solid ice. And in order for life to form, says Lipps, "that's the first thing you have to do... concentrate the elements of life."

Many people assume that icy environments are too cold to support life. When Lipps went to Antarctica to study its biology, he initially thought so too. "I went down there with all the biases that everyone always has, that its a terrible place, harsh, life can't get along there. But that's just absolutely wrong." Lipps saw life all over the place--fish swimming in the cold cold water, and microbes in the channels in the ice. "And I've come to the opposite conclusion: that life really loves ice."

NASA scientists assumed that life on Europa, if it exists, would be deep under the ice. To get a look at it, we would need to drill through the icy crust and pull up some of the water beneath it. But Lipps disagreed. In Antarctica, there are fracture zones where ice is pushed up from the bottom to the surface. A similar process could occur on Europa, says Lipps; tides in Europa's oceans could grind up ice and force it to the surface.

So life could be transported from Europa's slushy innards to its frozen surface. But could it survive there?

Lipps says many scientists thought the solar radiation is "too fierce for life to exist on the surface... we'd last about 2 minutes." This is because scientists thought "Europa is like a cue ball: smooth. But it's not." Europa is covered in cracks and crevices, caverns and boulders and overhangs. "It's geologically extremely variable," says Lipps, providing life with plenty of places protected from the extreme radiation. "It only takes a meter and a half of ice to damp out that radiation." So life could potentially live just a meter and a half below the icy skin of Europa--essentially on the surface. And this, says Lipps, "freaks [people] out."

Based on his findings in Antarctica, Lipps made a list of habitat types where life could exist or where fossils could be found on Europa: in the oceans, on the sea floor near hydrothermal vents, and on the surface's icy shell, in impact craters, fissures, cracks, and lakes.

In addition to life itself, says Lipps, Europa's surface could show signs of life, called biosignatures. There could be fossils and other sorts of evidence, like chemicals or rock or ice structures that are indicative of life.

NASA had plans for a spacecraft, called Jupiter Icy Moons Orbiter (JIMO), which would one day travel to Europa and take photographs of its surface, focusing on the habitats on Lipps' list.

However, NASA's JIMO project was cancelled in 2005 and replaced by a new program, called Moon, Mars and Beyond. It is basically an ordered list of NASA's priorities, says Lipps, and "that essentially cancelled the ‘beyond' part."

Lipps has since started working on planetary protection: protecting other planets from ourselves, and protecting ourselves from alien life forms from other planets. There are tiny microbes that stow away on our spacecrafts, and these microbes could contaminate other planets. In one respect, "it's just environmental conservation," says Lipps.

But there is a second part to planetary protection: if we find life on another planet, we can't be sure that it is actually extraterrestrial--we may have inadvertently brought it from Earth. So we need to sterilize our spacecrafts before they are launched. The early Mars missions may have already contaminated Mars, says Lipps. Subsequent Mars missions have gotten around this problem by landing far away from the early landing sites.

How can we completely sterilize spaceships? We could do it with heat, says Lipps, "but you'd burn up the electronics." So Lipps leaves these technical questions to NASA's engineers. He just comes up with the possibilities. "Whenever I look at the marine environment from a ship, I tell the captain what to do... So I approach Europa in the same way," telling the engineers where a Europa-bound spaceship should land, in order to be near sites of biological and geological interest. It is of course easiest to land on a flat surface, but, says Lipps, "I don't want to land in a parking lot, I want to land on the side of a mountain. That's where the outcrops are, that's what I want to look at. [The engineers say] ‘Oh we can't do it.' Well think about it. Maybe we can."

Interplanetary missions require serious long term planning. And with the "beyond" missions on the backburner, it is almost certain that Lipps will never know if there is life on Europa. Is it difficult to plan missions that you will never see? "Yes," says Lipps. At first "it was a psychological shock," even for a geologist accustomed to thinking of time in millions of years. "It's really tough to accept that, to think that you put in that effort and then you never see the result." But that is no reason to stop asking these questions. "It's still science and it's still figuring out the puzzle and it's still exciting and fun, so I'll keep doing it."

Courses: Lipps teaches Astrobiology (IB 167), and The Biology and Geomorphology of Tropical Islands (IB C158), which is taught at the Gump South Pacific Research Station on the island of Mo'orea in French Polynesia. He sometimes teaches Paleontology of Protists and other graduate courses.

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