Evidence revealed yesterday of possible early Martian life is "tremendously exciting," said Toby Owen, Institute for Astronomy scientist involved with Mars space missions and studies of the planet from Mauna Kea.

"It's something we've been hoping for for a long time, that there might be some evidence of very primitive life on Mars," he said.

An electron image of a particle from the meteorite shows carbonate globules in yellow. Some scientists say organic compounds within these globules were deposited by primitive life forms. Associated Press

Scientists from around the world had a series of meetings this summer to discuss how Mars evolved and how it relates to the way Earth got its atmosphere and beginnings of life, Owen said.

"Mars is a wonderful test case for this because it preserves very ancient history on its surface, which the Earth has lost."

Owen was a science team member for the Viking mission that landed on Mars 20 years ago and he's a member of Mars missions planned by the Russians and Japanese. He has studied Mars with the Canada-France-Hawaii telescope on Mauna Kea and plans more observations this winter.

One of 12 Martian meteorites recovered over the last century yielded the discovery of what NASA Administrator Daniel Goldin said were "extremely small, single-cell structures that somehow resemble bacteria on Earth."

About half of the Martian meteorites were found under Antarctica's ice in the past 10 years. Some pieces are under study at the UH Institute of Geophysics and Planetology.

The Antarctic meteorites were traced to Mars by the composition of their gases, said Ed Scott, member of the research team headed by institute Director Klaus Keil.

He said the UH group is studying the rocks primarily to learn about the red planet's volcanic processes, lava flows and atmosphere.

Investigating tiny sections of three meteorites under the microscope, graduate student Rachel Freedman said, "In a way, it's hard to make a judgement on the whole planet from small segments. We're sort of piecing things together."

Scientists from other universities and the Johnson Space Center found the microfossil remains in rocks 4.5 billion years old.

"It's exciting and fascinating but it doesn't mean life evolved beyond that level, single cell life. But it would be kind of cool if it did," she said.

UH researchers, also including Jeff Taylor, are examining pieces about 1.3 billion years old, Freedman said. Some of the other Martian meteorites are believed to be as young as 180 million years, she said. "It gives us a view of different terrains and ages across Mars."

"The feeling now is pretty widespread that in its first billion years Mars must have gone through some periods when the atmosphere was much thicker than it is today," he said.

"And it was warmer then because of the greenhouse effect - the same thing we're worrying about on Earth - and at that time liquid water could have existed on the planet's surface.

"What's exciting about that to us," Owen added, "is that it was in the same billion years (between 4.5 billion and 3.5 billion years) when life began on Earth."

Scientists know there was life on Earth as early as 3.5 billion years ago because of fossil remains of simple bacteria in rocks, Owen said.

A lot of evolution occurred in the Earth's first billion years, he said. But that first billion years of history is missing from the Earth because the planet is so active geologically, he said.

"All we can say is conditions on Mars must have been close enough to conditions on Earth that if it happened here, it might have happened there."

Owen and a colleague from Israel are working on the idea that both Mars and Earth acquired all the gases, or elements needed for life, from comets.

He said that seems to be supported by the meteorites. "The reality looks as if Earth and Mars, and even Venus for that matter, started out with the same storehouse of elements and each proceeded along different paths.

"But certainly in the early history of Mars, life could have started. The trick is how did it survive under worsening conditions?" Possibly, it migrated underground, as in some cases on Earth, he said.

In his research from Mauna Kea, Owen said he'll be looking for methane, indicating presence of life, even microbial life. "It would be living underground if we find it, but it would be life that's alive today. So that would be pretty neat." Even if it's there, however, he said he thinks chances of finding it are pretty slim.

His main project, Owen said, is to look at carbon dioxide and water on Mars to better understand the history of its atmosphere - once very thick, now very thin, dry and cold. "Early on, it looks like water was running over the surface, forming ponds and craters. There were lakes. There may even have been small oceans, but all of that is gone."

The Martian horizon as seen in a three-image composite taken in 1976 by the Viking 2 Mars lander, the last successful mission to the planet. At least 10 more missions are planned to visit Mars through the year 2003. Associated Press