Post by WitchBoy on Jun 28, 2002 20:21:15 GMT -5
Scientists who claim there could never have been life on Mars have always pointed out that liquid water is needed for sophisticated life forms to exist. Even when it was discovered that water is trapped on Mars underground or in ice, the skeptics said only bacteria could survive such conditions. Now new images of the planet reveal Ma'adim Vallis, one of the biggest valleys on Mars, was formed when a large lake overflowed. If there was once enough water on Mars for a gigantic flood—where is it all now?
They think it all started when a was created by an asteroid impact 3 ½ billion years ago. Researchers at the National Air and Space Museum say a flood of water from a huge lake — large enough to flood both Texas and California —overflowed into the impact crater. When that crater filled up, says geologist Ross Irwin, the water eroded away a barrier and went cascading across the surface of the planet. Within a short time, the canyon called Ma'adim Vallis, which is the size of the Grand Canyon, was carved from the surface of Mars. The force and volume of the water was enough to carve a valley 6,900 feet deep and 550 miles long within a matter of months. "Imagine more than five times the volume of water in the Great Lakes being released in a single flood and you'll have a sense of the scale of this event," says Irwin.
The water is originally thought to have come from the rain or snow that fell when Mars had a warmer atmosphere that wasn’t as thin as it is now. Unlike Arizona's Grand Canyon, which took millions of years for the Colorado River to create, Ma'adim Vallis was made "within a matter of months, certainly less than a year," says Irwin. The Mars canyon gives us still more evidence that Mars, which is now a cold, dusty place with water existing only as buried ice, was once wetter and warmer. Some researchers estimate that up to 40 percent of the Martian surface could have been covered with water. No matter where the water went, Mars was once a perfect place for life.
Nobody knows for sure where all the water went, but theories suggest that some of it was chemically split up into hydrogen and oxygen. The hydrogen could then have escaped to space. The oxygen stayed on Mars, giving the planet its rusty, reddish color.
They think it all started when a was created by an asteroid impact 3 ½ billion years ago. Researchers at the National Air and Space Museum say a flood of water from a huge lake — large enough to flood both Texas and California —overflowed into the impact crater. When that crater filled up, says geologist Ross Irwin, the water eroded away a barrier and went cascading across the surface of the planet. Within a short time, the canyon called Ma'adim Vallis, which is the size of the Grand Canyon, was carved from the surface of Mars. The force and volume of the water was enough to carve a valley 6,900 feet deep and 550 miles long within a matter of months. "Imagine more than five times the volume of water in the Great Lakes being released in a single flood and you'll have a sense of the scale of this event," says Irwin.
The water is originally thought to have come from the rain or snow that fell when Mars had a warmer atmosphere that wasn’t as thin as it is now. Unlike Arizona's Grand Canyon, which took millions of years for the Colorado River to create, Ma'adim Vallis was made "within a matter of months, certainly less than a year," says Irwin. The Mars canyon gives us still more evidence that Mars, which is now a cold, dusty place with water existing only as buried ice, was once wetter and warmer. Some researchers estimate that up to 40 percent of the Martian surface could have been covered with water. No matter where the water went, Mars was once a perfect place for life.
Nobody knows for sure where all the water went, but theories suggest that some of it was chemically split up into hydrogen and oxygen. The hydrogen could then have escaped to space. The oxygen stayed on Mars, giving the planet its rusty, reddish color.
