Mike Wall, Space.com (January 3, 2010)
"A patch of land near the huge Martian volcano Olympus Mons may bear evidence of recent plate tectonic activity on the Red Planet, new research suggests.
"The many ridges and scarps on the rumpled apron of land north and west of Olympus Mons are likely signs of tectonic thrusting, according to the study. And this activity could be very recent — within the last 250,000 years or so.
"If the study's conclusions are confirmed, they would overturn conventional wisdom, which holds that plate tectonic forces are unlikely to have played a major role in shaping the surface of Mars - particularly in the recent past...."
(NASA and An Yin (UCLA), via Space.com, used w/o permission)
Hats off to Mr. Wall, the article's author, for taking time to explain some of the ideas involved in this new development of our knowledge (and speculation) of Mars:
"...'People don't want there to be plate tectonics on Mars,' said study author An Yin of UCLA, who presented his findings in December at the fall 2010 meeting of the American Geophysical Union in San Francisco. "But I think there's good evidence for it." [Mars map suggesting recent plate tectonic activity]
"A shifting surface?
"Earth's surface has been shaped over the eons by giant crustal plates that pull apart, smash together and dive under one another.
"These plates slide around on a layer of partially molten rock called the mantle. Earth's interior is hot enough for mantle rock to remain in a soft, relatively plastic state, partly because our planet is relatively large. The more massive a planet, the hotter it is on the inside.
"Mars is much smaller than Earth - about half as wide, and only 11 percent as massive. Consequently, many scientists think the Red Planet is too small, and its interior too cold, to host plate tectonic processes...."
The Lemming particularly appreciated the term, "half as wide." Too many writers use "big" in situations like this: leaving the reader to guess whether they mean diameter, volume, mass, or something else.
Mars (maybe) having recently-active tectonic plates is, first, unexpected. And still debatable. Debated.
Whether or not crustal plates on Mars moved around recently is important to the search for life on Mars, as well as the (geology?) of the planet. There's good reason to believe, as the article pointed out, that Earth's crust being recycled on a regular basis is part of what makes this a fit place to live.
Finally: "Recent" and 250,000 years may not seem to belong in the same sentence. That's a long time, on the scale we use to think about the World Cup or mortgage payments.
Looking at the 4,500,000,000-plus Earth - and Mars - have been around, though? 250,000 years ago is practically contemporary.
- "Mars, Mud Volcanoes, and the Search for Life"
(August 20, 2010)
- "New Look at the Lost Ocean of Barsoom"
(June 15, 2010)
- "Mars isn't Earth, Earth isn't Mars: And Why That Matters"
(May 12, 2010)
- "Earth May Not Be a 'Class M' Planet"
(December 5, 2009)
- "Ancient Lake on Mars - Maybe"
(June 20, 2009)