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Public Radio's Environmental News Magazine (follow us on Google News)

Moons & Money

Air Date: Week of

Astrophysicist Neil deGrasse Tyson tells host Steve Curwood why water spewing geysers may mean there’s life on one of Saturn’s moons, and how proposed budget cuts could affect the search for life and other space science programs.


CURWOOD: Scientists have found yet another place where there may be life beyond Earth. New data shows that one of Saturn’s moons has water--one of the essential elements of life--spewing from its surface.

And with me now is Neil deGrasse Tyson. Dr. Tyson heads New York's Hayden Planetarium, and is a regular contributor to our program. Welcome back to Living on Earth, Neil.

TYSON: Pleasure to be back, thanks.

CURWOOD: And it’s good to have you here. Hey, let’s talk about these new findings on one of Saturn’s moons. This moon is called Enceladus, and the information came from the Cassini spacecraft. What exactly did it find?

TYSON: Well, it found evidence of a plume rising up from the surface of this moon of Saturn. Saturn is far enough away so that anything out there is just frozen, and this moon is duly frozen on its surface. But then you have this plume rising up from a frozen surface, and that raised some eyebrows. And if you look at other auxiliary data you’re left with no other conclusion than that you have this pool of water under pressure beneath this frozen surface; and if you build up enough pressure, and you have the heating from Saturn, you can evaporate some of that water, and it’ll punch through and make a geyser just like what you have at Yellowstone National Park. Except these geysers are ice geysers rather than hot water geysers.

CURWOOD: What’s heating it up?

TYSON: Well, there’s several heating sources in the Saturn system. There’s a radiation field. There’s also the tidal forces of Saturn on the moon; they actually have a way of stressing the solid planet, the way when you hit a racket ball the ball starts to get warm because you stressed it and it punched back into shape. When you do that with a solid body you end up heating up the body, and what might have been frozen down beneath the surface begins to liquefy, and that action can create interesting sort of geological features and geological behavior for these moons. And Enceladus is not the only moon that demonstrates this heating and consequences from it; there are moons of Jupiter that do this, as well. So, we were well-equipped to interpret what we saw.

CURWOOD: So now, how does this all relate to the question of life beyond Earth?

TYSON: That’s an excellent question because… I heard a comedian joke, why do we spend all this money looking for water when it’s just something that comes out of your kitchen faucet? (Laughs)

CURWOOD: (Laughs)

TYSON: The difference is there are no aliens coming out of your kitchen faucet. I think. Water, on Earth, is always associated with life – liquid water, that is. Wherever you find water, you find life. Wherever you find life, you find liquid water. And so that shapes the way we pose our questions as we explore the solar system. We want to look for the water, and by doing so, we believe, significantly increases our chances of finding life. Or, more specifically, life as we know it. So water is always a tantalizing find whereever we discover it.

CURWOOD: By the way, where else in the solar system might there be life?

TYSON: Well, let me first tell you the places where there’s water. We still don’t know if there’d be life there; we need some more experiments. Certainly, Enceladus. We’ve got liquid water in Jupiter’s moon Europa. That one is also heated by the tidal forces of Jupiter, and we’ve been eyeing that one for quite some time, actually. In fact, there’s even a mission in planning, but not funded, to got to Europa and try to perform experiments that would search for life that may exist beneath the frozen surface.

Also top of the list, of course, is Mars. As a planet, Mars has all this evidence of once having had liquid water flowing on its surface. It may have even been an oasis. All of that’s gone now. Something bad happened on Mars, something we don’t know, and so the study of Mars can be extremely important if we want to keep the flowing of water here on Earth. So, this search for life can ultimately point right back to us for our own survival.

CURWOOD: Speaking of Mars, I was looking at that new site on Google, Google Mars, where you can just look at all the craters and dunes and everything. That’s so exciting.

TYSON: I’ve seen the Google Earth site. I have yet to check out the Google Mars site, but I’m completely jazzed by the idea. Because the Google Earth allows you to become even more familiar with Earth, not as just some place that has warring factions, but as an orb, as a planet. You can think of where you live on a planet rather than in a nation, for example.

And by doing the same for Mars it’s a good thing because it brings Mars into your office, or into your home, in the way Earth is brought into your home. And that’s how it ought to be, because the solar system is not someplace out there, it is our backyard. It is a space we share with other planets. And so the more of that, the more familiar we become with our cosmic environment, I think the more understanding we can bring to even our own planet.

CURWOOD: Neil, let’s turn to the NASA budget for a moment. As I understand it, while the overall budget goes up a little bit some things are being deeply cut. For example, the folks that study life, or the prospect of life, on other parts of the solar system – astrobiology is being cut. And some of the satellites that monitor the weather on the Earth, and climate systems, those are being cut. What’s going on here?

TYSON: Yeah, the cuts are not unique to Earth-monitoring or to astrobiology – they’re spread across many sub-disciplines within the sciences of NASA. And what has happened is there’s been a redistribution of monies within the agency to enable the shuttle to finish its directive to complete the construction of the space station. We have obligations to international partners to run that through its course. My hope is that by the time that’s done there can be a renewed era for NASA where we can redouble what has been a very successful science portfolio in the NASA activities over the past decades.

CURWOOD: Neil deGrasse Tyson is an astrophysicist and head of the Hayden Planetarium in New York. He’s also the new host of the PBS science magazine “NOVA ScienceNow” beginning this fall season. Neil, thanks for taking the time.

TYSON: Thanks for having me on.



Cassini Discovers Water on Saturn’s Moon Enceladus

Cassini Imaging Team Site

Google Mars (new interactive site)


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