Life On Mars

I was sitting at my desk when the Instant Messenger window opened up. It was Dave Brody. He had been our executive producer at SciFi when I hosted Inside Space.

Dave was excited about an announcement that had been made and exclusively reported by, where he now works:

Washington — A pair of NASA scientists told a group of space officials at a private meeting here Sunday that they have found strong evidence that life may exist today on Mars, hidden away in caves and sustained by pockets of water.

Here’s the full story if you’re interested. Dave and I have been through similar announcements before; specifically the Allen Hills Meteorite ALH84001&#185.

It is because of Dave that I actually got to hold that meteorite, safely sealed in a controlled environment, through a port in my rubber gloved hands

It would be astounding if life were actually found today, living on Mars. But hold on. To quote George Harrison, “What Is Life?” What these scientists consider life and what you and I probably think of when we hear the word are totally different.

I typed something like that back to Dave, who replied with his best read on what the first extraterrestrial life discovered might be. “Pond scum. Extremeophile&#178 Pond Scum.”

When scientists start talking about extraterrestrial life, they’re not talking about ET! They’re thinking about forms of life that I consider more chemistry that biology.

Still, Dave has a very important point that applies… even to the most rudimentary forms of life. “If it has our DNA, it means “they is us” (as Pogo once said).”

He’s right. I guess, that changes everything.

&#185 – From Wikipedia – A 4500-million-year-old meteorite found in the Allen Hills of Antarctica (ALH84001). Ejection from Mars seems to have taken place about 16 million years ago. Arrival on Earth was about 13000 years ago. Cracks in the rock appear to have filled with carbonate materials between 4000 and 3600 million years ago. Evidence of polycyclic aromatic hydrocarbons (PAHs) have been identified with the levels increasing away from the surface. Other antarctic meteorites do not contain PAHs. Earthly contamination should presumably be highest at the surface. Several minerals in the crack fill are deposited in phases, specifically, iron deposited as magnetite, that are claimed to be typical of biodepositation on Earth. There are also small ovoid and tubular structures that might possibly be nanobacteria fossils in carbonate material in crack fills (investigators McKay, Gibson, Thomas-Keprta, Zare). Micropaleontologist Schopf, who described several important terrestrial bacterial assemblages, examined ALH84001 and opined that the structures are too small to be Earthly bacteria and don’t look especially like lifeforms to him. The size of the objects is consistent with Earthly “nanobacteria”, but the existence of nanobacteria itself is controversial.

&#178 – Extremeophile seems to be an alternate spelling for extremophile.

An extremophile is an organism, usually unicellular, which thrives in or requires “extreme” conditions. The definition of “extreme” is anthropocentric, of course. To the organism itself its environment is completely normal. Non-extremophilic organisms are called mesophiles.

What Is Life?

The two NASA robots continue to poke around on the surface of Mars. We are explorers – even robotically. The difference between these explorers and a Columbus type explorer is what they’re looking for.

Back in the 15th Century, man was looking for a shortcut to goods he could use. If the trips were successful, spices, gold and other treasures would come back on a triumphant return. At the moment, nothing’s coming back from Mars.

Today’s explorers have a somewhat more ethereal goal. We’re looking for signs of life, the origins of life, the origins of our universe. It’s heady stuff. It’s exploration in the abstract. Unlike the 15th Century, there may be no practical payoff.

Today the AP reported; “Mars rover Opportunity has found evidence that the Red Planet was once wet enough for life to exist there, but the robot has not found any direct traces of living organisms, NASA scientists announced Tuesday.

Of course, the next step will be to look for signs of life. But (with apologies to George Harrison) what is life? It’s not a stupid question. If you’re thinking people, insects, plants, you’re way up the ladder from where scientists will look. In fact they will be looking for incredibly simple forms of life – forms so simple, that to me, it’s difficult to separate life from simple chemistry.

A few years ago I went to NASA’s Johnson Space Center in Houston to look at ALH84001, the Allen Hills meteorite. Some scientists believe this chunk of Mars, which through an unbelievable confluence of events ended up on Earth, holds fossilized evidence of Martian life. But the fossils are so simple, the life so rudimentary, that most lay people would yawn and turn away. That’s how I feel about its fossils – though the story of how it got to Earth and how why scientists know to go to Antarctica to find meteorites is more than a little fascinating.

Over the next few months, NASA will probably use the results of this incredible engineering triumph to try and fund more missions, and people will start talking about searching for life. Just remember, it might not mean what you first thought.