Posted: Sat Feb 12, 2005 5:03 pm
<a href='http://liftoff.msfc.nasa.gov/News/2001/ ... arming.asp' target='_blank'>Here's the link.</a><br><br><!--QuoteBegin-Some Genius at NASA+--> <table border='0' align='center' width='95%' ><tr><td class='quotetop'><b>Quote:</b> (Some Genius at NASA)</td></tr><tr><td class='quotebody'> Global Warming for Mars <br><br>Could a terraformed Mars be in the future?<br><br>Mars is a very chilly place -- and that's an understatement! The annual mean temperature on the Red Planet is 55 degrees C below zero. That's about the same as the winter temperature at the South Pole on Earth. Brrrrrr! <br><br>If humans ever build communities on Mars, we will want to find a way to turn up the warmth of that planet. To learn more about making Mars a better place to live in the future, NASA recently sponsored a conference called "The Physics and Biology of Making Mars Habitable." Among the topics discussed was how to make Mars more comfortable. <br><br>One idea is to pump enough so-called "greenhouse" gases into the air on Mars to create a runaway greenhouse effect. Here on Earth, the thought of a runaway greenhouse effect is very alarming. But on Mars it's a plus, say scientists who study ways to terraform Mars. The idea is to warm up Mars enough for all of the planet's available carbon dioxide (CO2) -- which is now trapped in ice and frosts -- to evaporate into the atmosphere and help keep the planet's temperature up. <br><br>But there are two problems. First, even if all of Mars' available CO2 were coaxed out, it wouldn't necessarily warm the planet enough to make it comfortable for humans, because no one knows just how much CO2 is there. Second, the best way to get Mars to release its CO2 easily is, well... to warm it up. <br><br>Margarita Marinova, a college student at the Massachusetts Institute of Technology, thinks she has an answer to both problems: use man-made chemicals called perfluorocarbons (PFCs) to start warming Mars. Margarita has been studying the warming effects of PFCs, along with Chris McKay of NASA's Astrobiology Institute. <br><br>PFCs have several advantages, according to Margarita. First, they are super-greenhouse gases. A little bit of them does a lot of warming! Second, PFCs have a very long lifetime. On Earth, these are serious problems, but would be positive factors on Mars. Further, PFCs don't have negative effects on living things.<br><br>Unlike their chemical cousins called "chlorofluorocarbons" (or CFCs), PFCs do not destroy ozone. Ozone in Earth's atmosphere provides protection for living creatures against harmful ultraviolet (UV) radiation. Building up an ozone layer in the air of Mars would be an important goal for terraformers. Mars has only a very tiny amount of ozone at present and it needs to be increased as a UV protector, Margarita says. <br><br>Sunlight arrives at a planet's surface mostly as visible and ultraviolet light. The planet absorbs this solar energy, and then radiates warming infrared energy back out into the air. Greenhouse gases in the air work as a layer of global insulation, trapping the infrared radiation and preventing it from escaping away into space.<br><br>Carbon dioxide and water are good at trapping some of this infrared energy, but not all of it. On Earth, there's so much CO2 and water in the atmosphere that it doesn't matter if some of the infrared radiation escapes out into space. But on Mars, we will want to trap all the heat we can, and the right mix of PFCs could do the job well. <br><br>"When we first start warming Mars," explains Margarita, "we'll want to cover the whole range of infrared radiation." Once CO2 is released by the planet, she says, it will take over part of the job. Then PFCs will only need to be used where warming is weaker. <br><br>But how fast can Mars be heated up? <br><br>Margarita says it depends on how fast PFC gases are made. By rough calculations, 100 PFC factories -- each with the energy of a nuclear reactor -- working for 100 years could warm the planet Mars by six to eight degrees. At that rate, raising Mars' average temperature up to the melting point of water (from -55 degrees Celsius now) would take about 800 years! <br><br>It wouldn't really take that long, Margarita points out, because those figures don't include the boosting effect of CO2 that would be set free as Mars got warmer. She also says that creating better super-greenhouse gases could make it happen faster.<br><br>Human habitation of Mars is a long way off. NASA's current Mars exploration plans for the next 20 years do not include any manned mission to Mars. By the time people actually settle on Mars and can begin the task of terraforming it, advances in technology may make it much easier to warm its atmosphere than any way being studied today by scientists like Margarita Marinova.<!--QuoteEnd--></td></tr></table> <!--QuoteEEnd--><br><br>Better idea: Let's ship our greenhouse gases over there before it's too late for us!