"Now, we also appreciate the high salinity of the water when it left behind the minerals Opportunity found. "At first, we focused on acidity, because the environment would have been very acidic," Knoll says. Inspection suggests that, instead, it was at the top of an underground water table, Squyres reports.Įxperiments with simulated Martian conditions and computer modeling are helping researchers refine earlier assessments of whether the long-ago conditions in the Meridiani area studied by Opportunity would have been hospitable to microbes. Scientists previously hypothesized this material might preserve a record of the ground surface from just before the impact that excavated the crater.
Opportunity spent recent months examining a bright band of rocks around the inner wall of a crater. "All of Spirit's most important findings, such as evidence for hot springs or steam vents, came after the prime mission." "The engineering efforts that have enabled the rovers' longevity have tremendously magnified the science return," says Steve Squyres of Cornell University, principal investigator for the rovers' science payload. At a meeting of the American Association for the Advancement of Science in Boston, scientists and engineers discussed on Friday new observations by the rovers, recent analysis of some earlier discoveries, and perspectives on which lessons from these rovers' successes apply to upcoming missions to Mars. Opportunity and its twin, Spirit, began their fifth year on Mars last month, far surpassing their prime missions of three months.
"Not all water is fit to drink," says Andrew Knoll, a member of the rover science team who is a biologist at Harvard University. Like salt used as a preservative, high concentrations of dissolved minerals in the wet, early-Mars environment known from discoveries by NASA's Opportunity rover may have thwarted any microbes from developing or surviving. NASA/JPL-Caltech/Cornell University February 18, 2008 This view from NASA's Mars Exploration Rover Opportunity shows bedrock within a stratigraphic layer informally named "Lyell," which is the lowermost of three layers the rover has examined at a bright band around the inside of Victoria Crater. And if you're harnessing every watt of energy pouring out of every star in the galaxy, who'd miss a little extra energy being used for communications. Physicists predict that civilizations will eventually advance to the point that they master all the energy of their home planet, their star system, and eventually their entire galaxy. Why bother sending out puny radio signals when you can harness the energy of an entire star. The advantage to this, of course, is that stars are visible for tremendous distances. From long distances, astronomers wouldn't be able to resolve the individual stars, but they'd definitely know something strange was going on. With 16 stars in formation, you'd have a shape that mother nature would never arrange on her own, but would be stable for long periods of time. Imagine binary systems, orbiting binary systems, orbiting binary systems. One interesting suggestion, made to Lanier by Piet Hut at the Institute for Advanced Study is a multiply nested binary system. The more stars you put into formation, the better your message will be. With this technique, and a few million years to time to kill, you could line up stars into a formation that shows an intelligence was behind it.
Over a long period of time (a really really long period of time), you could impart enough of a velocity change to drive your star anywhere you wanted it to go. These objects could rain into the inner Solar System and prod the Sun's motion through the galaxy. Send out a fleet of these spacecraft to tinker with the orbits of Kuiper Belt objects. Over a long period of time, you can move the asteroid enough in its orbit to prevent it from striking the Earth. By flying a spacecraft near an asteroid, and fighting against the gravity pulling it down, you can actually pull the asteroid off course. In order to actually move a star requires a gravitational tractor, and engineers are already planning this kind of a mission for a threat closer to home: asteroids.
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