JUDY WOODRUFF: Finally, some tantalizing new findings about water on Mars.
Naturally, it raises more questions about the possibility of some kind of extraterrestrial
life there.
It's a perfect fit for our Miles O'Brien and our weekly segment on the Leading Edge of
science.
Amna Nawaz caught up with him.
AMNA NAWAZ: They may have long suspected it, but scientists have finally found for the
first time a large watery reservoir, possibly a lake, beneath the southern ice cap of Mars.
Radar suggests the reservoir is more than 12-miles-wide and similar in some ways to
lakes found beneath the Greenland and Antarctic ice sheets on Earth.
It's salty and buried nearly a mile below the three-billion-year-old ice cap.
For many, it's a huge moment.
And that includes Miles, who's long been covering the latest on the Red Planet, and joins me
now.
Miles, for those of us who haven't been following the Red Planet all the years, why is this
such a big deal?
MILES O'BRIEN: Well, Amna, I guess scientists, myself, and anyone who watches this closely
would have been surprised if they didn't find liquid water beneath the surface.
But it's not an easy thing to do.
You know, really, when you think about this, this is the culmination of about 150 years
of work that began with an Italian astronomer by the name of Schiaparelli, who trained his
telescope on Mars and saw what he called canali, which, translated, should mean channels, but
got mistranslated into canals, and really started off a whole trend which led us to
"The War of the Worlds" and the idea that there were really Martians.
This has gone on recently with NASA missions, including the Pathfinder missions, the Curiosity,
Spirit, and Opportunity missions, where there was all kinds of inferences of past water,
mineralogical data, that sort of thing.
Finally, the discovery of water ice at the poles.
So, think about it for a moment.
You have got all this evidence of distant, ancient water.
You have got water ice at the poles.
You know you have a hot core in the middle.
So if there's a hot core in the middle, water ice at the poles, somewhere along the way,
there has got to be water.
And that's what they discovered.
And the significance of that is, on this planet, wherever we find liquid water, no matter where
it is, bottom the ocean, in a hot acidic bath in Yellowstone, underneath a glacier in Antarctica,
wherever that may be, you find life.
AMNA NAWAZ: It's a huge moment.
Let's talk about how we got here in the first place.
What have they been looking at?
What did they use?
How do we know that the water is there?
MILES O'BRIEN: It's a European orbiter by the name of Mars Express.
It's been an orbit for 15 years.
And it has a radar device.
It has this long-wave radar.
It's kind of ground-penetrating radar that's been looking, analyzing beneath the surface
of Mars for all this time.
The data goes back really about a decade.
And the scientists have just been trying very carefully to make sure what they thought they
saw is what they thought.
And, in fact, after all these years of going through all the possibilities of what it might
or might not be, they have come to the conclusion it just has to be water.
And scientists I have talked to today say it's a very elegant piece of science.
There's a radar return about a mile-and-a-half below the surface of the south pole ice that
is clear-cut signs of liquid water.
AMNA NAWAZ: OK, so let's hear from one of the scientists who was actually the lead on
this research.
He's a planetary scientist in Italy.
This is him talking about exactly what they did find there.
Take a listen.
ROBERTO OROSEI, National Institute of Astrophysics: The radar data tell us that this water must
contain a large amount of salts.
This is because the ice above it is very transparent.
And this wouldn't be possible if the ice was too warm, too close to the melting point.
So, we have to conclude that the water in contact with the ice must be at least minus-10,
minus-20, maybe minus-30 Celsius.
AMNA NAWAZ: So, Miles, very salty water, very cold water.
You mentioned life where there is water.
What can actually live in these conditions?
MILES O'BRIEN: Well, your tiny, microscopic things, but that might be the extent of what
we ultimately find -- and it won't be easy to do, but maybe down the road -- in the way
of Martians.
It's important to understand that, you know, at that temperature, you would think it'd
be solid.
But if it's a briny solution, if it's a salty solution, and under pressure, which is what
you would have in this case, it can stay at liquid form at much lower temperatures.
And that part of Mars is a very cold place, indeed.
The question is, how would you ever verify if there were microbes there?
That would require some drilling.
And when I say that, some significant drilling, more than a mile-and-a-half deep at the south
pole.
AMNA NAWAZ: So is that what's next?
We're going to possibly see missions to drill on Mars?
MILES O'BRIEN: Well, the devil is in the details on that one, for sure, Amna....
(LAUGHTER)
MILES O'BRIEN: ... because, if you think about what it takes to do, you know, "Armageddon"-style
drilling with Bruce Willis on Mars, it involves a lot of very heavy machinery and drill bits,
which is very expensive and way beyond our capabilities right now to get to Mars.
One of the scientists I was talking to today, the principal investigator on Spirit and Opportunity,
Steve Squyres said, you know, if there's water there, it's very likely it is in the mid-latitude
regions, which would be a better place for humans to go anyway.
And it might be at a shallower depth, because it's warmer there.
So maybe, just maybe, they could do some drilling mid-latitudes, and it would be not as deep.
But, either way, it's not an easy mission.
So it'll be -- we will have to sort of stay tuned as to whether there are microbes in
this underwater lake in -- on Mars.
AMNA NAWAZ: We will be staying tuned, indeed.
We know you will as well.
Miles O'Brien, always great to talk to you.
MILES O'BRIEN: Amna, it's a pleasure.