tagged w/ SOL
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A recent, prolonged lull in the sun's activity did not prevent the Earth from absorbing more solar energy than it let escape back into space, a NASA analysis of the Earth's recent energy budget indicates.
An imbalance like this drives global warming — since more energy is coming in than leaving — and, because it occurred during a period when the sun was emitting comparatively low levels of energy, the imbalance has implications for the cause of global warming.
The results confirm greenhouse gases produced by human activities are the most important driver of global climate change, according to the researchers.
They found that the Earth absorbed 0.58 watts of excess energy per square meter than escaped back into space during the study period from 2005 to 2010, a time when solar activity was low. By comparison, the planet receives 0.25 watts less energy per square meter during a solar minimum, than during a period of maximum activity in the sun's 11-year cycle. (Currently, the sun is in the midst of Solar Cycle 24, with activity expected to ramp up toward solar maximum in 2013.)
"The fact we still see a positive imbalance despite the prolonged solar minimum isn't a surprise given what we've learned about the climate system," lead researcher James Hansen, director of NASA's Goddard Institute for Space Studies, said in a statement. "But it's worth noting, because this provides unequivocal evidence that the sun is not the dominant driver of global warming."
However, in an email to LiveScience, Hansen noted that "the sun is a small but not negligible factor," in determining the size of the imbalance. Over the past decade, the imbalance declined slightly due, in part, to the solar minimum, according to Hansen. [Gallery: Our Amazing Sun]
Solar activity refers to the activity of the sun's magnetic field. Fluctuations in solar activity, including magnetic field-powered sunspots and solar flares, have been linked to past changes in climate, including, controversially, the Little Ice Age. Some skeptics have attributed contemporary climate change to natural fluctuations in solar activity, rather than human-emitted greenhouse gases — the explanation endorsed by nearly all climate scientists, including those convened by the Intergovernmental Panel on Climate Change.
Incoming solar radiation is measured by satellites; the recent minimum set records for the reduction in solar radiation since satellite measurements began in the 1970s.
http://www.livescience.com/18255-solar-cycle-climate-change-warming.htmlA recent, prolonged lull in the sun's activity did not prevent the Earth from... more
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Marc Jacobs lanzó al mercado una línea de lentes oscuros que se caracterizan por tener las varillas con rayas multicolores.Marc Jacobs lanzó al mercado una línea de lentes oscuros que se... more
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Can a single picture sum up all of 2010? In a way, yes. The above multiple-exposure photo shows the figure-eight path of the sun over the course of the entire year, known as an analemma.
Analemma photographs are made by taking a picture of the sun from the same place at the same time of day once or twice a week, generating 30 to 50 frames. This picture, made in Veszprem, Hungary, combines 36 photos of the sun taken at 10 a.m. local time between January and December. A separate picture of the neighborhood taken from the same location but at a different time of day was digitally composited into the foreground.
The sun makes this shape over a year because Earth rotates on a slightly different axis than the sun, and our planet also travels on an elliptical orbit. As one hemisphere of Earth tilts farther from the sun, the arc of the sun's daily path seen from that location lowers toward the horizon. The sun's arc then gets higher in the sky as the tilt reverses. The sun's highest point in the sky, seen in this analemma, occurs during the summer solstice, while its lowest point is during winter solstice. (Find out about a lunar eclipse that happened on the 2010 winter solstice.)
Because of the time and precision involved, photographs of analemmas can be very difficult to produce. So far, only about 20 people worldwide have released successful analemma photos, according to Babak Tafreshi, founder of the astrophotography website The World at Night (TWAN).
http://news.nationalgeographic.com/news/2010/12/photogalleries/101228-sun-end-year-analemmas-solstice-eclipse-pictures/#/year-in-picture-analemma-sun-path-eclipse_30692_600x450.jpgCan a single picture sum up all of 2010? In a way, yes. The above multiple-exposure... more
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The unfurling of a Japanese solar sail, the first demonstration of a new space propulsion technology, went exactly according to plan.
According toJAXA’s blog posts and photos from the event, the IKAROS spacecraft’s sail appears to be in place. It’s a big step in its attempt to travel driven only by sunlight.
“This is the first sail ever deployed in space, and if they succeed in using it for solar-sail flight — it’ll still be a few weeks before we know that — it’ll be a milestone,” said Louis Friedman, executive director of the Planetary Society, an organization dedicated to promoting space exploration, which is readying its own solar-sailing mission.
A solar sail uses the pressure from photons striking its surface to push the spacecraft through space. Materially, the 650 square-foot sail is made of incredibly thin, aluminized plastic that’s only 0.0003 inches thick, a little thicker than spider silk, or about the diameter of a red blood cell. When a photon strikes its surface, it bounces off, imparting its momentum to the sail. Each photon might not deliver much thrust, but over time, all that light adds up.
“The actual force might be just a few millionths of a g, but because it acts continuously, it allows you to build up large velocity changes over time,” Friedman said. “That’s where a sail really does its work is long missions.”
The Japanese sail also has thin-film solar cells built into it. They could be used to generate electricity to drive an engine that would work alongside the sail.
The key difficulty with such a thin and large object is that it’s hard to deploy. “The things we’re watching for are all their dynamical behaviors that you ultimately can’t model and that might cause undue stress on the material,” Friedman said.
In the IKAROS design, the sail was unfurled by using centrifugal force generated by spinning the craft.
Space-travel proponents are particularly interested in the technology because it doesn’t require fuel, which makes it the leading (and basically) only candidate for very long-distance travel.
“It’s the only way we know — that anybody knows — to ultimately do practical interstellar flight because you don’t have to carry your propellant along with you,” Friedman said. “Anything else you do, whether it’s nuclear or advanced engines, you’re always carrying propellant and the mass becomes too great.”
Read More http://www.wired.com/wiredscience/2010/06/solar-sail-deployment#ixzz0qUZaKojeThe unfurling of a Japanese solar sail, the first demonstration of a new space... more
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"Sol" will be premiering at the 2008 Santa Barbara International Film Festival! Festival dates are Jan. 24th-Feb. 3rd. Go to sbiff.org for more info!
Sol is the best skateboard video to come out of the Central Coast area since "Fulfill the Dream". It features Ross Norman, Jeremy Cannon, Sean Bolis, and Pablo Favela, along with special appearances by; Jesse Silvey, Steve Quellar, Riley Muraoka, Dustin Semenza, Beto Guerrero, and Masaki Itoi.
Filmed by Santa Barbara area filmers, Anthony Petti, Marty Osborn, and Adriano Caldas.
Edited and Produced by Erik Hatch (Fulfill the Dream, Guilty, Underdog)
"Sol" will be premiering at the 2008 Santa Barbara International Film... more
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See what happens when nine people volunteer to live and work together in a house that focuses on everything from compost and farming to food justice. Check out what happens when people continue being polite and start getting really into sustainable development...The Real Environmentally Cool World: Oakland.See what happens when nine people volunteer to live and work together in a house that... more
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