After all, the Earth and Mars are not thought to be much older than 4.5 billion years and the first incontrovertible evidence of life here - bacteria and algae - does not appear in the fossil record until 3.1 billion years ago. From those primitive organisms, we evolved. So why should precisely the same sort of processes not have taken place on Mars?
What raises the stakes in such speculation is the existence of remarkable evidence that complex artificial structures - monuments, gigantic edifices - may have been built on Mars at some remote date. These structures, detected in NASA video images sent back by the Viking Orbiter in 1976, have never been photographed since but have become the focus of a widening controversy over the past 20 years.
Because they include several enormous pyramids and a massive Sphinx-like face, an apparently lunatic fringe argues that they must be the work of intelligent and technologically advanced beings. A civilization, in other words.
Scientists have officially opposed this view, asserting that the structures are not structures at all but tandem geological patterns.During the thousands of millions of years after that rock and its fossils formed on Mars there was ample time for incredibly primitive organisms to have become much more complex - perhaps even forms capable of developing a civilization.
After all, the Earth and Mars are not thought to be much older than 4.5 billion years and the first incontrovertible evidence of life here - bacteria and algae - does not appear in the fossil record until 3.1 billion years ago. From those primitive organisms, we evolved. So why should precisely the same sort of processes not have taken place on Mars?
What raises the stakes in such speculation is the existence of remarkable evidence that complex artificial structures - monuments, gigantic edifices - may have been built on Mars at some remote date. These structures, detected in NASA video images sent back by the Viking Orbiter in 1976, have never been photographed since but have become the focus of a widening controversy over the past 20 years.
Because they include several enormous pyramids and a massive Sphinx-like face, an apparently lunatic fringe argues that they must be the work of intelligent and technologically advanced beings. A civilization, in other words.
Scientists have officially opposed this view, asserting that the structures are not structures at all but tandem geological patterns.
Increasingly, however, even the most orthodox academics have begun to sound less sure. Earlier this year, for example, several months before the discovery of signs of life in a Martian meteorite, Professor Car Sagan, of Cornell University in the U.S., made a significant admission. The Face on Mars, he said, was 'probably sculpted by slow geological processes over millions of years'. Nevertheless, he also said: "I could be wrong. It's hard to be sure about a world we've seen so little of in extreme close-up."
Sagan urged that forthcoming American and Russian missions to Mars should make a special effort "to look much more closely at the pyramids and at what some people call the Face and the City.
COHERENT SHAPES
A casual glance reveals only a jumble of hills, craters and escarpments. Gradually, however, as though a veil is being lifted, the blurred scene begins to feel organized and structured - too intelligent to be the result of random natural processes.
Although the scale is grander, it looks the way some archaeological sites on Earth might look if photographed from 1,000 miles up.A72 by Dr. Tobias Owen, who is now professor of astronomy at the University of Hawaii. The same frame, covering approximately 34 by 31 miles - also shows many other features that could be artificial.
These cluster around latitude 40 degrees north in the region of Marsk known to astronomers as Cydonia, and were photographed from an altitude of more than 1,000 miles with relatively poor resolution.
A casual glance reveals only a jumble of hills, craters and escarpments. Gradually, however, as though a veil is being lifted, the blurred scene begins to feel organized and structured - too intelligent to be the result of random natural processes.
Although the scale is grander, it looks the way some archaeological sites on Earth might look if photographed from 1,000 miles up.
