Was Mars like Earth at one point?

Matthew Golombek, who is one of this world's most noted experts on Mars, believes the red planet once may have been like Earth. Whether organisms lived or live there, he adds, nobody knows yet.

Golombek is chief scientist of NASA's science operations team leader for the Spirit and Opportunity rovers that are beaming back photographs and data from the surface of Mars. A senior research scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., he will speak Wednesday in a free public lecture at the University of Utah.

Golombek's book, "Mars: Uncovering the Secrets of the Red Planet," was published by the National Geographic Society, and he is author of almost 400 scientific papers, abstracts and articles, says a U. release.

He will give the "Frontiers of Science" lecture starting at 7:30 p.m. in the Aline Wilmot Skaggs Biology Building auditorium. The topic is Mars' climate change from wet to dry.

"The compelling story about Mars is there is a fair bit of evidence to suggest the environment early on in its history — say about 3.9, 4 billion years ago — could have been very similar to Earth's," Golombek said in a Deseret Morning News telephone interview.

At that time, Mars may have been warm enough and wet enough for liquid water on the surface, he said. Those conditions are key to life as we know it.

But how can anyone know about conditions on that distant planet, billions of years ago? The answer came with the streams of data from the remote-controlled rovers, which have been trucking across the desert of Mars and using their cameras, spectrometers and other instruments for the past three years.

"The rovers found evaporate rocks that were left behind from the evaporating salty sea water," he said. Salts remain on the surface long after the seas dried.

"We have compelling evidence that these rocks were deposited in very salty conditions, and actually somewhat acidic conditions as well," he said. "Liquid water appears to have been stable at the surface at that time."

Life began on Earth roughly 3.9 billion years ago, he noted. "Did life start on Mars?" Are we an accident of the highest order, he asked, or is life "commonplace, and will form anytime liquid water's stable?

"And we don't know that." It is a compelling question, Golombek said, that we can address by going to nearby planets and studying conditions there.