|Eve Of The War
|Ben Bova: We're learning more about Mars
|Page 1 of 1|
|Author:||eveofthewar [ Sun Jun 04, 2006 4:08 pm ]|
|Post subject:||Ben Bova: We're learning more about Mars|
By Ben Bova
FROM : Naplenews.com
There's a delicate ballet going on around the planet Mars.
After a seven-month journey from Earth, a robotic spacecraft is now looping around the red planet, dipping into its thin atmosphere to slow itself down so that it can eventually settle into a circular orbit.
The Mars Reconnaissance Orbiter is the largest and most sophisticated probe ever to study Mars. At 2.4 tons, it's more than twice as big as any of the previous spacecraft sent there.
MRO will study Mars' atmosphere, its rust-red surface, and even peer beneath the surface with ground-penetrating radar in an effort to detect permafrost: water frozen underground.
Previous orbiters and landers have detected tantalizing hints that water once flowed across the Martian surface in ages past.
Today, Mars is a pole-to-pole frozen desert where overnight temperatures plunge to a hundred degrees below zero or colder. The Martian atmosphere is thinner than our Earth's high stratosphere.
Mars certainly looks like a dead, frozen, arid world. But was it always this way? Was there once a warmer, wetter Mars? Did life once exist there? Does some form of life still exist on Mars today? That's what is so fascinating about Mars. The possibility that this neighbor world may have once harbored life. Or might still.
When people start to think about the possibilities of life on other worlds they first turn their thoughts to Mars, the red planet.
"Martians" are the archetype for extraterrestrial creatures, thanks in large part to H.G. Wells, whose 1898 novel The War of the Worlds has fixed in the public's mind the idea of malevolent intelligent aliens.
The famous 1938 Halloween broadcast of Wells' story by Orson Welles added a new shudder of fear: thousands of radio listeners actually believed that New Jersey was being invaded by Martians. (But how intelligent could the aliens be if they wanted to invade New Jersey?) In the late 19th century, many respected astronomers gave serious thought to the idea that life might exist on Mars.
With the telescopes of that day, Mars was the only planet whose surface could be seen. It looked distinctly Earthlike. Mars is tilted on its axis almost exactly as Earth is. It revolves in almost the same period as Earth: 24 hours, 37 minutes. There are ice caps at its poles, which shrink in the summer and grow in the winter.
In 1877, the Italian astronomer Giovanni Schiaparelli reported seeing straight-line markings on the rust-red disk of Mars. He called them canale, which in Italian means "channels." But the term was immediately taken by many to mean "canals." Canals on Mars? That would mean there must be canal builders on Mars.
In 1893, Percival Lowell, a wealthy Boston businessman, moved to Flagstaff, Arizona, where he spent the rest of his life studying Mars.
Lowell was certain that there were intelligent Martians, desperately crisscrossing their dying world with canals to bring water from the ice caps at the poles to the parched regions closer to the equator.
Lowell saw a vast network of canals on Mars. They even seemed to grow darker in the Martian springtime, presumably because more water was flowing through them as the ice cap melted.
Most professional astronomers pooh-poohed Lowell's ideas. They showed evidence that Mars was too cold and too dry to support life.
Besides, most of them didn't see any canals and nobody saw the intricate network of canals that Lowell did.
In those telescopes of the 19th century, Mars was a faint reddish disk that faded in and out of focus. Eyestrain was a persistent problem: astronomers had not yet started to use cameras to record what they saw; they peered through their telescopes for long hours and drew sketches of what they observed.
Lowell was not only a persistent observer. He was a very successful writer. His books about a dying Mars peopled by diligent canal builders were tremendously popular, even though most professional astronomers regarded them with disdain, if not disgust.
Even worse, as far as academia was concerned, Lowell's concept of Mars became the basis for fantastic fiction by the likes of H.G. Wells and, later, Edgar Rice Burroughs.
Yet, it was those lurid tales by Burroughs that inspired a youngster named Carl Sagan to spend his life investigating the possibilities of life on Mars — and elsewhere in space.
It turns out that the canals Lowell saw were mainly the result of eyestrain. The professionals were right and Lowell was, to say the least, overly optimistic. Once spacecraft began probing Mars in the 1960s they found that there were no canals, and no canal builders.
But those space probes began to build up evidence that Mars was once warmer than it is now. They photographed channels in the red sands where water must have once flowed. They detected chemical evidence that some of the Martian rocks were once immersed in water.
So the search goes on. The Mars Reconnaissance Orbiter is merely the latest robotic vehicle to study the red planet. There will be more.
Eventually, human explorers will set their boots on those rust-red sands.
Will they find fossils of long-extinct organisms? Or perhaps even living creatures, such as the lichen that live inside rocks in the frozen wastes of Antarctica's dry valleys? Or colonies of bacteria dwelling deep underground? After all, such bacteria live a mile or more below ground here on Earth, eating solid rock.
The search will continue because human beings yearn to know whether our world is the only place where life exists. If we find life on Mars — extinct or extant — we will know at last that we are not alone.
Nobody expects intelligent canal builders on Mars. But maybe farther out, on worlds orbiting other stars? Who knows?
Naples resident Ben Bova is the author of more than 110 books, including "Faint Echoes, Distant Stars," a nonfiction study of the search for life in the universe Bova's Web site is www.benbova.com.
|Page 1 of 1||All times are UTC|
|Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group