September 12, 1996

McGill researcher continues the hunt for life on Mars

by Sylvain Comeau


Dr. Hojatollah Vali

A few weeks after the media frenzy, Hojatollah Vali still doesn't know what hit him. Vali, a geoscientist in the Department of Earth and Planetary Sciences, was one of the researchers who announced to the world in early August that they had discovered possible evidence of life on Mars within a potato-sized chunk of meteorite. The resulting whirlwind of publicity stunned the softspoken, reflective Vali.

"At the press conference (organized by NASA in the U.S.) I expected to see a few reporters waiting for us. Instead it was a big room full of excited people."

As the sole Canadian representative from the scientific team, Vali spent a week going from one interview to the next, with seemingly every radio station and newspaper in town wanting a piece of him. The media coverage of perhaps the biggest story of the year was exhaustive, but Vali is concerned by a certain lack of depth in the reporting of the discovery.

"Not one story I saw mentioned our research paper (in the August 16 issue of Science magazine). The only thing that counts in this discovery is the science."

Vali's part in the science behind the hype was to determine, using electron microscopy, that magnetite and iron sulfide particles found on the meteorite were unlikely to have occurred without the help of organic microorganisms, based on similar particles found on earth which normally do not occur through inorganic means.

Magnified image of fine-grained magnetite and iron sulfide particles of possible biogenic origin on the Martian meteorite's surface

The rest of the team discovered four other pieces of evidence, including amplified images from the meterorite "resembling terrestrial microorganisms, documented terrestrial biogenic carbonate structures, or micro-fossils," according to the research paper.

Vali is careful to emphasize that the team's findings are not conclusive proof, are open to scientific interpretation, and need further study. And he makes an important distinction when asked the $10,000 question: how sure are you that this discovery indicates life?

"That depends on how you define life. Based on what we saw, the probability of biogenic activity is 70%. For life, less than 50%." The difference is subtle but significant: "With life, you might think of something moving, being active, like a developed bacteria. Biogenic activity could mean something much simpler than bacteria: very basic microorganisms, maybe composed of just a membrane, which we don't know of here on earth and which are capable of some chemical reactions."

Somewhat surprisingly, Vali is not ready to scoff at the notion of intelligent life elsewhere. He doesn't expect to see any little green men, but Vali will admit that the Mars discovery, and other recent ones on earth, have got him thinking differently about life.

"Every day we learn something new. Recently a scientific paper reported finding a thermophilic microorganism, one which lives at high temperatures, producing magnetites. I didn't know that before, and I wouldn't have believed that five years ago.

"If microorganisms can live in such harsh conditions--at 165C--how can we know if a higher life form couldn't also survive in harsh conditions on other planets? I wouldn't be surprised, because that's evolution--adaptation to the environment."

The meteorite, designated ALH84001 for the Allan Hills icefield in Antarctica where it was found, comes to us from deep inside inside Mars and is estimated to be 4.5 billion years old. The current theory is that meteors and asteroids hitting Mars blasted a crater in the planet, and that a second impact sent loose rocks from the crater into space.

Eventually, after an estimated 15 million years, one landed in Antarctica 13,000 years ago and in 1996 became world famous. But Vali and his colleagues would like more samples than the few that conveniently fell to earth. They hope to get a chance to study rock samples taken directly from Mars.

"NASA is hoping to send a landing vehicle to Mars in 2001 or so. If that happens, we will get to work on samples from the surface and subsurface. The surface of Mars is frozen and exposed to strong ultraviolet radiation from the sun, but we would expect to find layers of sediment near the surface and if there is life, that's where it might be found."

Other follow-up studies will involve more earthly material. "We have samples from Antarctica and the North Pole which are exposed to permafrost, similar conditions as on Mars. There are microorganisms within these rocks, and if we can determine what they are doing, it may enhance our understanding of the microorganisms which might have existed inside the meteorite."

Vali is going to NASA for six months starting in January, but he hopes to do most of the follow-up work at McGill. "The Department of Cell Biology and Anatomy has one of the best electron microscopy facilities in North America and it has been essential to my research over the past few years. I also plan to work with the departments of Chemistry and Biology as we look into biological activities on Mars."

That spirit of collaboration may eventually extend even further. Earth and Planetary Sciences has conducted preliminary discussions with both NASA and the Canadian Space Agency to conduct joint research and to establish a Centre for Space Science Research at McGill.

"We are discussing with them the possibility of doing more research in universities, which is far less expensive than research in space," says Earth and Planetary Sciences chair A.E. Williams-Jones.

Though pleased with his team's discovery, Vali likes the long-term approach. "We shouldn't jump to conclusions based on one study. This should just be a scientific contribution, and we should have a chance to work on it and come up with more results. Why don't we just take this as a first step--the beginning of an investigation?"

Fourth rock from the sun

Mars is a slightly pear-shaped planet, smaller than Venus or Earth, and rotates around the sun in 687 days

The landscape is a dusty, red, eroded lava plain. Red atmospheric dust is kicked up by winds of up to 125 mph/200 kph, giving the planet a pink sky. Recorded temperatures vary from -148F/-100C to 32F/0C

The atmosphere is 95% carbon dioxide, 3% nitrogen, 1.5% argon and 0.15% oxygen. The atmospheric pressure is 7 millibars, equivalent to the pressure 22 mi/35 km above Earth

There are four enormous volcanoes near the equator of the planet. The largest, Olympus Mons, is 15 mi/24 km high with a crater 40 mi/65 km wide

Studies of Mars in 1985 showed that enough water might exist to sustain prolonged missions by space crews

Reactions to the possibility of life on Mars

"If the results are verified, it is a turning point in human history, suggesting that life exists not on just two planets in one paltry solar system, but throughout this magnificent universe."
-Astronomer and author Carl Sagan

"I hope it's true with all my heart, but this is nonsense. There's just no proof. Ted Koppel called last night and asked me to be on Nightline, but I refused because I didn't want to be a grouch."
- Ray Bradbury, author of "The Martian Chronicles"

"It's so unsurprising. It's not evoking in me and most paleontologists any wondrous new thoughts because we've been well aware of the likelihood that Mars was habitable for at least a billion years of its history."
-Harvard paleontologist Stephen Jay Gould

"If they found intelligent life, meaning human life, it would violate everything we know and believe as Christians."
-Evangelist Jerry Falwell

"The good effect of this discovery is to keep our imaginations open. The great obstacle to progress is not ignorance but the illusion of knowledge. Perhaps this little rock will destroy the illusion that we are alone in the universe."
-Historian Daniel Boorstin

Links to other sites

McGill Earth and Planetary Sciences Life on Mars page

NASA site

Science Magazine

New Scientist

Federation of American Scientists

CNN Interactive

More links (Yahoo!)