Q and A

Karen Meech
Image: karen meech

Local astrobiologists seek ancient water on Earth

Karen Meech / As a faculty member at the University of Hawaii at Manoa and the leader of the UH branch of NASA’s Astrobiology Institute, Karen Meech considers some of the biggest of the big questions. One of her main areas of interest is water, and how its presence makes planets conducive to life. Next week, she’s giving a talk titled, “When and How Did Our Planet Become Conducive to Life?” as part of the Institute for Astronomy’s Frontiers of Astronomy Lecture series. Honolulu Weekly caught up with Meech beforehand to talk about everything from subsurface oceans to UFOs.

One of your areas of expertise is astrobiology. Tell me about the kinds of questions astrobiologists seek answers to.

Well basically, astrobiology is an exploration of life, how it originates, where in the solar system might be suitable places for life and how you make the ingredients for life in space.

So, easy ones then.

[Laughs] Right. Where in the solar system might you find a habitable world? At one point, Mars, from a distance, looked like it had a much more clement environment. More recent space stations have shown intriguing possibilities for icy moons in the outer solar system, which seem to have subsurface oceans like Jupiter’s moon, Europa. Saturn’s moon, Titan, has also recently been found to have some source of water underneath its ice. It’s a big moon that has a really thick atmosphere. It’s a very interesting world that has weather and geology and very interesting organic components. Of course all of this gets back to the really intriguing question of how did it all start on Earth? Are we completely unique?

Let’s go back to subsurface oceans, and talk a bit about what their presence on any given planet might indicate.

So for example, the large moon of Jupiter, Europa, it’s always been known–even from Earth-based observations–to have a lot of ice on it. When the Voyager got there, it had a very bizarre surface, not many craters on it. It’s basically an icy surface with a lot of cracks on it, a whitish moon with brown cracks. There’s an ocean beneath this icy surface and cracks have developed and some of that liquid has oozed up above the surface.

They don’t know how deep it is but the intriguing thing about it is you have liquid water and organic compounds on the surface that have oozed up from the ocean. That’s pretty far out in the solar system and it’s very cold, so there must be an energy source that’s keeping it liquid. This means you’ve got water, food and energy: all the ingredients for life.

What is the energy source out there?

Tides, tidal interaction with Jupiter, that squeeze the moon as it orbits Jupiter and keeps it warm inside the planet.

What are some of the biggest misconceptions you hear people have about the universe?

Oh God, that’s huge. [Laughs] That’s like saying, “Define life, tell me the history of earth.”

That was my next question.

Most people have a lot of misconceptions. You sit on an airplane and people ask what you do and you say, “astronomy,” and they spin off the latest theory about what they’ve heard and it’s usually wrong. UFOS are popular. People constantly confuse astronomy and astrology, too.

So what’s the latest theory worth sharing with the next astronomer I meet on a plane?

Well, I specialize in comets. I went to an astrobiology meeting in Iceland in 2004, and we went to a geothermal field where you saw huge plumes of steam coming out of the earth. And this woman said, “Oh you can go over and touch it, it’s cool. And it’s probably primitive water from the ancient world.”

There had been research in the 1980s and 1990s that comets were contributors to Earth’s water. But the way they were substantiating it was comparing the chemistry of ocean water to the chemistry of water from comets. But ocean water cycles through the upper Earth crust–so how can ocean water be primitive?

When she said maybe the water from plumes was primitive, I started thinking maybe that was the water we should measure. It turns out she was wrong in that case, but there may be primordial water that has never mixed with the oceans, deep within the earth, and some of that comes up from rocks.

I’ve actually been to Iceland collecting rocks myself with a rock hammer, not a tool I would have expected to using as an astronomer.

Why Iceland?

Both Iceland and Hawaii have a specific type of volcano called hotspot volcanoes, where the land is effectively moving across a really deep source of magma that’s coming from deep within the Earth, so it is bringing up rocks that could contain water that hasn’t mixed with water from the ocean. You slice the rocks, make very, very thin sections of them, and you can study the chemistry.

How do you determine which water is which?

One fingerprint of whether the gases of that rock have ever mixed is to look, not at water, but at helium. Helium’s isotopes, some versions are heavier than others and the proportions were actually made in space when the universe was created. On Earth, helium was produced radioactively. The other kind was produced in space, and the two have different ratios. If you happen to have something that has never mixed with Earth material, it should still show the ratio it had in space. If you pick a rock up that came from deep within the earth and it has this space-ratio in helium, then that’s the rock you want to test the water in.

We may never have the exact answers but the process of trying to figure out why earth has water at all is going to lead us to some interesting and surprising results. And it’s fundamentally important because water is essential to life.

Forgive me, but I have to ask about life on other planets.

There has got to be life out there, although I think the first life we ever discover will be microbial. If you take a 24-hour clock on our planet and look at when life appeared, it just happened, just in the last little bit of time. Of course, the real interesting thing for a lot of people is will we find intelligent life. I do think within our lifetime they will have an answer as to whether or not there are detectable signals of intelligent life in the vicinity of our solar system. You never know unless you look.

UH Art Building Auditorium, Wed 3/31, 7:30pm, free, [ifa.hawaii.edu]