Johnald's Fantastical Daily Link Splurge |
- How to Make an All-Instant Thanksgiving Dinner
- How to Catch Microbes Hitchhiking to Mars
- Aerial Art Sends Climate Message
- Pulsing Stars Could Fill in for GPS Satellites
| How to Make an All-Instant Thanksgiving Dinner Posted: 24 Nov 2010 10:22 AM PST
It's the day before Thanksgiving, and you forgot to reserve a turkey. Or maybe you are short on time, or just really lazy and don't want to actually cook the meal. Either way, modern food science has the entire turkey day menu covered: Just add water. We put together an all-instant menu, made up of only room-temperature foodstuffs requiring, at most, boiling water or a microwave to prepare. No baking, barbecuing, broiling, frying, grilling, roasting, sauteing or stewing necessary. When it comes to instant gratification, freeze-drying is king, we're told by Washington State University food engineer Juming Tang. And it preserves flavor while making food inhospitable to bacteria. "It was developed in the 1950s, and gives you the highest quality product over canning, pickling and other food-preservation techniques," Tang said. "But it's also the most expensive, about three to 10 times as much." So if you are ready to boil and microwave your way out of any kind of really labor-intensive Thanksgiving preparations, here's what you need. Turkey |
| How to Catch Microbes Hitchhiking to Mars Posted: 24 Nov 2010 09:31 AM PST
Microbial stowaways on Mars rovers could raise false alarms for astrobiologists hoping to find evidence of life — or worse, could wipe out native Martians waiting in the soil. A new study suggests that current techniques for cleaning Mars rovers could let some of the hardiest life forms, single-celled salt-lovers and tiny animals called tardigrades, slip through. "We might actually select for these organisms," said Adam Johnson, a graduate student at Indiana University and lead author of a paper to be published in the journal Icarus. "They would be the most likely thing to be able to survive." Johnson and colleagues subjected some of Earth's toughest life forms from the most extreme environments they could find to 40 days in a mockup Mars environment. The subjects included bacteria from Siberian permafrost; single-celled microorganisms called haloarchaea from briny saltwater in Mexico; yeastlike organisms from cold saline springs in the Canadian arctic; and tardigrades (also known as water bears), the world's toughest multicellular animal, which have been known to survive trips into space. "We threw a lot of organisms at the experiment," Johnson said. "A lot of studies just focus on one, but we really just threw the kitchen sink at it."
The researchers cooked up a batch of simulated Martian soil, called regolith, from volcanic basalt rocks taken from two different outcrops in Oregon. They baked the mixture for 12 hours at 750 degrees Fahrenheit to make sure it was free of organic materials. Then they mixed carefully measured samples of the organisms into the soil, and let the concoction sit in a glass chamber meant to simulate the Martian atmosphere for a week. After that first week, Johnson set the chamber to mimic the daily temperature variations, solar cycle and ultraviolet radiation at the Martian surface for 40 days. Earlier studies had found that the single biggest threat to Earthly microbes was ultraviolet radiation, but being buried in just a millimeter of soil could protect organisms enough to keep them alive. Johnson and colleagues expected organisms that like extreme cold, called psychrophiles, to fare best in the negative-40-degree Martian nights. Surprisingly, cold-loving critters dropped off quickly in their first week in the chamber, when temperatures were held at a balmy 50 degrees Fahrenheit. "Really temperature and atmosphere doesn't matter," Johnson said. "It seemed to be the actual conditions of the regolith and [the organisms] themselves that determined the chance of survival." Most of the creatures died from drying out, or from the harsh chemical conditions in the fake Martian soil. "They become almost mummified," Johnson said. "It looks like organisms go almost into a freeze-dried type state." The only organisms that made it were the salt-loving haloarchaea from Mexico, and the hardy tardigrades. Tardigrades can slow down their metabolisms by a factor of 10,000 under harsh conditions, allowing them to dry up without dying. Based on their success in the simulated Mars chamber, Johnson thinks they could last more than 300 days on Mars. "This is the first study where we've actually shown that an organism could potentially last for several hundred days on the surface of Mars," he said. Current techniques for sterilizing spacecraft use dry-heat treatments and chemicals similar to those that could be produced in the Martian soil. Whatever organisms survive those treatments are also the most likely things to survive and thrive once they reach Mars, Johnson said. "Everybody knows that this is not the greatest way to go about it, but that's the way they do it," said astrobiologist Rocco Mancinelli of the SETI Institute, a coauthor of the paper. "I personally think it has to be revamped." "This paper points out the need for ongoing re-examination and updating of sterilization and detection methods used for planetary protection purposes during cleaning and preparation of spacecraft," said Margaret Race of the SETI Institute, who studies how best to avoid contaminating Mars with earthly life, and vice versa, but was not involved in the new study. "We are continuing to find microorganisms that surprise us in their hardiness." Image: Brett's Blog See Also:
Follow us on Twitter @astrolisa and @wiredscience, and on Facebook. |
| Aerial Art Sends Climate Message Posted: 24 Nov 2010 09:18 AM PST << Previous | Next >>  With a series of large-scale artworks visible from above, activists at 350.org hope to harness the power of aerial imagery to raise environmental consciousness beyond the local, drawing attention to climate policy in ways that statistics do not. The organization's name comes from what climate scientists say is the upper limit on atmospheric carbon dioxide levels. Beyond 350 parts per million, climate change will likely outpace the ability of natural and human systems to adapt. As of now, atmospheric CO2 is about 390 ppm. The artworks precede next week's United Nations climate-policy meeting in Cancun, where negotiators will try to strike a global deal on fossil fuel emissions. Their last attempt, in Copenhagen one year ago, ended in failure. Since then, the global weather has become even weirder, with extreme events — heat waves in Russia, floods in South Asia, megastorms on the U.S. East Coast — fitting predicted climate-change patterns. In the United States, still the world's major producer of greenhouse gases, a bipartisan climate-change bill failed. It's easy to become cynical about the situation. But the people filling a dry riverbed in these images and forming other symbolic messages in the other images in this gallery still have hope.
Top: Girl Scouts, church groups and other local citizens in Santa Fe, New Mexico, stand with blue tents and posters in the Santa Fe riverbed./DigitalGlobe and 350.org. Bottom: Don Usner/350.org See Also:
Brandon's Twitter stream, reportorial outtakes and citizen-funded White Nose Syndrome story; Wired Science on Twitter. |
| Pulsing Stars Could Fill in for GPS Satellites Posted: 24 Nov 2010 08:57 AM PST
To find your favorite coffee shop in an unknown city, getting directions via satellite works like a charm. But that technology won't get you from Earth to Jupiter.
Unlike the Global Positioning System of satellites used in cars and smart phones, the pulsar positioning system wouldn't need humans to make daily corrections. "You could be on a spacecraft and you could be able to navigate without having any help from Earth," says Angelo Tartaglia, a physicist at the Polytechnic University of Turin in Italy.
Though the navigation system proposed by Tartaglia and colleagues is just a proof of concept, a GPS-like system under construction in Europe called Galileo could implement the ideas within a decade, he says. The principle behind the pulsar positioning is not too different from ordinary GPS. The GPS receiver in a car or phone receives radio signals from satellites orbiting the Earth. The satellites are synchronized with atomic clocks to emit signals simultaneously. Because the satellites are all different distances from the receiver, each message reaches the device at a different time. From those time differences, a GPS device infers the distance to each satellite, and hence can calculate its own position. The best consumer devices can pinpoint your location to within a meter under ideal conditions, but tall buildings or other interference can throw them off by 10 to 20 meters or more. Because the satellites move so fast (they orbit the Earth twice every day), Einstein's special theory of relativity must be considered. Relativity requires that clocks on board tick slower than those on Earth. After two minutes, the satellite's clocks are already out of sync with Earth clocks. Transmitting the correct time to each satellite is a constant chore for the Department of Defense, which determines the real time from an ensemble of clocks on Earth. A pulsar's regular blips can be used to tell time just like the signals received from GPS satellites. But the math in the new pulsar-based system already accounts for relativity, so those corrections aren't necessary. Pulsars, the dense leftovers of supernovae that sweep beams of radiation from their poles, serve as really good clocks, in some cases comparable to atomic clocks. Plus, a pulsar doesn't move much relative to the Earth in the time between its pulses, and the distance it does move over several months is predictable. Instead of tracking real pulsars, the Italian team simulated its proposed navigation system on computers by using software that mimics pulsar signals as if they were received at an observatory in Australia. The researchers recorded these fake pulses every 10 seconds for three days. Inferring the distance between the pulsars and the observatory, the team tracked the trajectory of the observatory on the Earth's spinning surface to an accuracy of several nanoseconds, or the equivalent of several hundred meters, the team reported in a paper posted at arXiv.org on October 30. Pulsars are extremely weak sources, however, and detecting them normally requires a large radio telescope—a heavy payload for spacecraft. So the researchers propose to create their own sources of pulsing radiation by planting bright radio wave emitters on celestial bodies like Mars, the moon or even asteroids. At least four sources have to be visible at a time to determine a position in the three dimensions of space and one dimension of time. Including just one particularly bright radio pulsar outside the plane of the solar system would be ideal because it would be the tip of a tetrahedron, a configuration that would make calculations more accurate, Tartaglia says. Or, you could look for pulsars that emit X-rays, a much brighter signal. X-ray antennas are also smaller and lighter, says physicist Richard Matzner at the University of Texas at Austin. Their drawback is oversensitivity to electrons surrounding the Earth. But an X-ray–based positioning system could pinpoint an object to within 10 meters, an improvement on the 100-meter or so accuracy of the radio pulsar system. Either system would be accurate enough to track a spacecraft speeding at 19,000 meters per second, the maximum speed the exploratory spacecraft Cassini reached zipping past the Earth in 1999 on its way to Saturn. It's easy to calculate a satellite's position along the line of sight by measuring Doppler shift —the change of frequency with an object's speed — but more difficult to create a three-dimensional picture of a spacecraft trajectory, says Scott Ransom, an astronomer at the National Radio Astronomy Observatory in Charlottesville, Va. A pulsar system could track those three dimensions and detect if the spacecraft was straying from its course. Pulsar-based systems may not be as precise as GPS, but they could be a backup system for GPS if the ground control for the satellites fails. "It would be better than nothing," says Matzner. "It's an insurance policy." Image: A Chandra X-ray observatory image of the Crab Nebula's pulsar. NASA/CXC/SAO/F. D. Seward, W. H. Tucker, R. A. Fesen See Also: |
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