Posted on 02/17/2004 3:44:06 PM PST by ambrose
Using Titan to Understand Earth and Mars
Tue Feb 17, 7:37 AM ET
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By Robert Roy Britt Senior Science Writer, SPACE.com
Plans have just been finalized for the Cassini spacecraft's exploration of Saturn's moon Titan, a giant world with a composition that resembles early Earth. Scientists expect the distant moon to help them understand the general nature of wind, oceans and how things might once have been on our home planet as well as Mars.
The investigation, which gets underway this summer, could also help theorists better model Earth's changing climate and the ultimate effects of global warming.
Titan is half the size of Earth and the only moon in the solar system with an atmosphere, which is loaded with methane and, like Earth's air, some nitrogen.
Ralph Lorenz, of the Lunar and Planetary Lab University of Arizona, presented the finished exploration plan over the weekend in Seattle at a meeting of the American Association for the Advancement of Science (news - web sites). It calls for 44 flybys of Titan over four years by Cassini after it arrives at Saturn this July. The craft will also deploy a probe to the surface of the moon next year.
Last week, Lorenz discussed with SPACE.com what he and colleagues hope to learn from Titan.
He explained that wind, waves and ocean currents are well understood only as they relate to current conditions on Earth. Scientists want to better grasp the underlying physics -- including what happens in wildly different conditions -- so they can predict how the natural world would react to change.
"We know that given the various factors that the result is X," Lorenz said. "We don't know for example, which of the factors is most important, or how the result will change if we change factor Y."
Earth's climate is heavily dependent on the transport of heat from equatorial regions to higher latitudes of the ocean and the atmosphere.
"Without, for example, the Gulf Stream, Northern Europe would be inhospitably cold, like much of Canada or Siberia at the same latitude," Lorenz said. "We don't know whether global warming might cause that ocean circulation to shut down. The only tool we have for studying that sort of effect is computer modeling, and that has many uncertainties. Observing Titan's ocean circulation and climate will give us more data to refine these models."
Cassini launched in 1997 and studied Jupiter on its way toward Saturn. It has taken a long, looping path that included flybys of inner planets to get gravitational boosts that saved fuel and reduced mission costs.
Lorenz works on Cassini's radar mapping team and is a co-investigator of the Surface Science Package on the Huygens probe, which will sample the atmosphere before landing Titan or splashing into an ocean. Huygens' measurements will complement various observations made by Cassini during the flybys, from radar mapping to optical and near-infrared imaging and a probe of the moon's gravity field.
"It's an absolute bonanza of science in many different fields," Lorenz said.
If Titan has seas, their composition will be markedly different from those on our planet.
Last year, observations by the Arecibo radio telescope suggested Titan has oceans of methane and ethane -- what we call natural gas on Earth. Because Titan's surface is about -290 degrees Fahrenheit (-179 Celsius) both compounds would be liquid in the Titan seas.
How will waves and tides behave? How do these waves sculpt beaches? How deep are the seas and what is their relationship to the atmosphere?
Lorenz thinks answers to these and other questions could sharpen idea about early Mars, which is thought to have harbored oceans or lakes that might have been water-based.
"We don't know very well how to predict what the wind generation would be like with a different atmosphere and gravity," he said. "By seeing the process in action on Titan, we'll be able to make better predictions."
Titan also looks to scientists like a ripe, prebiotic world. It is perhaps similar to Earth in its early era, before life developed. Theorists will try to use Titan's chemistry, once explored, to figure out how our own planet made the leap from lifeless to life bearing.
"Titan is the largest single unexplored piece of real estate in the solar system," Lorenz said, "and with an atmosphere and probably a hydrological cycle as well, it's likely to be the most interesting."
Here it is:
Even if not -- even if it's just a sea of LNG -- I think it's time to stop referring to earth's hydrocarbons as "fossil fuels".
Unless, that is, we're prepared to assert that the various "methane planets" were once teeming with life, and in truly staggering amounts.
Parts of the "early earth" ARE still here though.
Those amazing robots. The mission is still being designed long after launch.
Translation: It's an absolute bonznza of taxpayer funded largesse to scientists
Dishonest 'scientist' alert.
In your opinion and the opinions of the hogs feeding at the public trough anyway. However, the reality is a bit more complex. Scientific exploration comes at a cost, and for every billion spent on looking at new pictures of extraterrestrial rocks and dust there is a billion dollrs not spent on things that the people who actually earned it have as priorities.
The top 1% of taxpayers pay 38% of the taxes, so if we figure about 80,000,000 taxpayers (not sure on this number) then 800,000 people are paying .38*$820,000,000 or about $1025 each to support engineers and PhDs whose sole product is pictures of rocks and dust. At the other end of the spectrum the lowest 50% only pay 3% of the taxes, so to Joe Schlub the Mars pictures only cost $0.62 Easy to see why some people don't care. Less than one lotto ticket to most.
You seem awfully willing to squander other peoples' money on things that you think are a good idea.
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