Global Warming on Mars
Photos may show Earth-like activity on Mars
By Bruce Lieberman
UNION-TRIBUNE STAFF WRITER
September 21, 2005
Mars is still nothing like Earth, but earthquakes and global warming may be changing the face of the Red Planet, new NASA photos taken from orbit suggest.
The emerging picture of a geologically old but still evolving world is exciting to Mars scientists, who hope to learn whether life did or ever could exist there.
The latest findings, made by comparing photos taken by a camera aboard NASA's Mars Global Surveyor spacecraft, were announced yesterday.
"What the Mars orbital camera has revealed from this long and detailed study of the Red Planet is a dynamic Mars, a planet that can change – not on the mind-boggling millions and billions of years, but on the order of years and decades," said Michael Meyer, chief scientist for NASA's Mars Exploration Program.
The discovery of recent changes on Mars were made after analyzing images at Malin Space Science Systems, a Sorrento Mesa company that designed the camera aboard the Mars Global Surveyor. The spacecraft has been orbiting Mars 249 miles above its surface since Sept. 12, 1997.
Placing photographs side by side, researchers at the company discovered mysterious gullies appearing on the walls of sand dunes in less than three years, tracks from boulders that had tumbled down the steep wall of a crater between November 2003 and December 2004, dramatic melting of ice at the south pole over three consecutive martian summers, and even a meteorite crater that hadn't existed 20 years ago.
The boulder tracks have particularly interested scientists. Exactly what may have shaken the boulders loose is unclear. Strong winds could have dislodged them, but researchers yesterday said they couldn't rule out a "marsquake."
"Seismic activity would be my guess, and it would be the first evidence that we have of anything like that," said Mike Malin, principal investigator for the Mars Orbiter Camera on NASA's Mars Global Surveyor, and head of Malin Space Science Systems.
It's not unreasonable to suspect that Mars does have occasional quakes, although the planet today is essentially geologically inactive, the scientists said. Confirmation that one or more earthquakes caused the boulders to fall would be significant because that would mean Mars is still warm enough to have rock move beneath the ground.
That in turn might suggest that volcanism is still occurring on Mars – generating enough heat to maybe support primitive life deep beneath the surface of the planet, said Jack Mustard, a geologist at Brown University in Providence, R.I.
On the surface, Mars looks mostly cold and dead – pummeled by meteorites and eroded by billions of years of wind storms. With an atmosphere of mainly carbon dioxide and some water vapor, it orbits the sun from an average distance of 143 million miles – compared with 93 million miles for Earth. The Red Planet's thin atmosphere and its distance from the sun make average temperatures 81 degrees below zero.
But scientists suspect that Mars may have had a very different past. Spacecraft in orbit and on the surface have found evidence suggesting that water may have been abundant billions of years ago. Some of the more intriguing finds include geologic features that resemble river beds, delta regions and large basins.
Two NASA rovers have roamed the planet since early last year searching for evidence of past water, and one of them has found compelling evidence. More missions are planned to hunt for the chemicals essential for life. Last month, NASA launched its Mars Reconnaissance Orbiter, which will search for evidence that water persisted on the surface long enough to provide a habitat for life.
In the meantime, the discoveries announced yesterday suggest that Mars is still a dynamic place, even if it's a pale shadow of its youth.
Two photographs discussed yesterday, one taken July 17, 2002, and the second taken April 27 of this year, show that gullies down the face of a sand dune formed at some point in between those two dates.
It's unlikely water would have formed the gullies because liquid water would have trickled down into the sandy dune before it was able to flow downhill, said Malin.
Instead, the gullies may have formed after carbon dioxide frost, trapped by windblown sand during the martian winter, vaporized rapidly in the spring, he said. The release of carbon dioxide gas could have made sand flow as a fluid that carved the gullies.
Malin said he has seen a similar phenomenon in Antarctica, where water ice can be incorporated into sand dunes.
At Mars' south pole, an escarpment of frozen carbon dioxide has retreated nearly 10 feet a year over the past three summers.
"It's evaporating now at a prodigious rate," said Malin.
The significance of this is Mars is experiencing climate change, or has experienced climate change."
Why Mars may be warming is a mystery, he said.
Bruce Lieberman: (619) 293-2836; bruce.lieberman@uniontrib.com
http://www.signonsandiego.com/news/science/20050921-9999-1m21mars.html
By Bruce Lieberman
UNION-TRIBUNE STAFF WRITER
September 21, 2005
Mars is still nothing like Earth, but earthquakes and global warming may be changing the face of the Red Planet, new NASA photos taken from orbit suggest.
The emerging picture of a geologically old but still evolving world is exciting to Mars scientists, who hope to learn whether life did or ever could exist there.
The latest findings, made by comparing photos taken by a camera aboard NASA's Mars Global Surveyor spacecraft, were announced yesterday.
"What the Mars orbital camera has revealed from this long and detailed study of the Red Planet is a dynamic Mars, a planet that can change – not on the mind-boggling millions and billions of years, but on the order of years and decades," said Michael Meyer, chief scientist for NASA's Mars Exploration Program.
The discovery of recent changes on Mars were made after analyzing images at Malin Space Science Systems, a Sorrento Mesa company that designed the camera aboard the Mars Global Surveyor. The spacecraft has been orbiting Mars 249 miles above its surface since Sept. 12, 1997.
Placing photographs side by side, researchers at the company discovered mysterious gullies appearing on the walls of sand dunes in less than three years, tracks from boulders that had tumbled down the steep wall of a crater between November 2003 and December 2004, dramatic melting of ice at the south pole over three consecutive martian summers, and even a meteorite crater that hadn't existed 20 years ago.
The boulder tracks have particularly interested scientists. Exactly what may have shaken the boulders loose is unclear. Strong winds could have dislodged them, but researchers yesterday said they couldn't rule out a "marsquake."
"Seismic activity would be my guess, and it would be the first evidence that we have of anything like that," said Mike Malin, principal investigator for the Mars Orbiter Camera on NASA's Mars Global Surveyor, and head of Malin Space Science Systems.
It's not unreasonable to suspect that Mars does have occasional quakes, although the planet today is essentially geologically inactive, the scientists said. Confirmation that one or more earthquakes caused the boulders to fall would be significant because that would mean Mars is still warm enough to have rock move beneath the ground.
That in turn might suggest that volcanism is still occurring on Mars – generating enough heat to maybe support primitive life deep beneath the surface of the planet, said Jack Mustard, a geologist at Brown University in Providence, R.I.
On the surface, Mars looks mostly cold and dead – pummeled by meteorites and eroded by billions of years of wind storms. With an atmosphere of mainly carbon dioxide and some water vapor, it orbits the sun from an average distance of 143 million miles – compared with 93 million miles for Earth. The Red Planet's thin atmosphere and its distance from the sun make average temperatures 81 degrees below zero.
But scientists suspect that Mars may have had a very different past. Spacecraft in orbit and on the surface have found evidence suggesting that water may have been abundant billions of years ago. Some of the more intriguing finds include geologic features that resemble river beds, delta regions and large basins.
Two NASA rovers have roamed the planet since early last year searching for evidence of past water, and one of them has found compelling evidence. More missions are planned to hunt for the chemicals essential for life. Last month, NASA launched its Mars Reconnaissance Orbiter, which will search for evidence that water persisted on the surface long enough to provide a habitat for life.
In the meantime, the discoveries announced yesterday suggest that Mars is still a dynamic place, even if it's a pale shadow of its youth.
Two photographs discussed yesterday, one taken July 17, 2002, and the second taken April 27 of this year, show that gullies down the face of a sand dune formed at some point in between those two dates.
It's unlikely water would have formed the gullies because liquid water would have trickled down into the sandy dune before it was able to flow downhill, said Malin.
Instead, the gullies may have formed after carbon dioxide frost, trapped by windblown sand during the martian winter, vaporized rapidly in the spring, he said. The release of carbon dioxide gas could have made sand flow as a fluid that carved the gullies.
Malin said he has seen a similar phenomenon in Antarctica, where water ice can be incorporated into sand dunes.
At Mars' south pole, an escarpment of frozen carbon dioxide has retreated nearly 10 feet a year over the past three summers.
"It's evaporating now at a prodigious rate," said Malin.
The significance of this is Mars is experiencing climate change, or has experienced climate change."
Why Mars may be warming is a mystery, he said.
Bruce Lieberman: (619) 293-2836; bruce.lieberman@uniontrib.com
http://www.signonsandiego.com/news/science/20050921-9999-1m21mars.html
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