Thursday, May 19, 2011

Recent Astronomy Images and News

Here's some amazing footage of the sun from NASA's Solar Dynamics Observatory



Those flares can cause magnetic fields that affect the earth and display as auroras like this:

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Here are two photos of Mars taken by the Mars Reconnaissance Orbiter. The first shows "swirls of tracks left by dust devils" and the second "the bedrock on the floor of a crater near Noachis Terra"

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There are more images here. Mars has a very varied landscape.

NASA reports Free-Floating Planets May Be More Common Than Stars. "Astronomers have discovered a new class of Jupiter-sized planets floating alone in the dark of space, away from the light of a star. The team believes these lone worlds are probably outcasts from developing planetary systems and, moreover, they could be twice as numerous as the stars themselves. 'Although free-floating planets have been predicted, they finally have been detected,' said Mario Perez, exoplanet program scientist at NASA Headquarters in Washington. '[This has] major implications for models of planetary formation and evolution.'"

NASA also wrote, NASA's Galaxy Evolution Explorer Helps Confirm Nature of Dark Energy. "A five-year survey of 200,000 galaxies, stretching back seven billion years in cosmic time, has led to one of the best independent confirmations that dark energy is driving our universe apart at accelerating speeds." "The results tell us that dark energy is a cosmological constant, as Einstein proposed."

io9 reports on a Nature article, The Earth’s core melts and freezes all at the same time. "The researchers examined heat flow at the boundary between the core and the mantle. In areas like the Pacific Ring of Fire, the tectonic plates are undergoing subduction, which involves one of the plates being pushed underneath into the other and into the mantle below. Because the crust is cooler than the mantle, this subduction process causes a net loss of heat in the mantle. As the subducted ocean plates sink to the bottom of the mantle, they begin to suck up heat from the core itself. All this exacerbates the freezing process down in the core. But here's where things get interesting - it's also possible for plate tectonics to produce the opposite effect. There are areas beneath Africa and the Pacific Ocean where the plates are so large that very little heat can escape upwards, meaning the mantle is hotter than average. This in turn means that there is less heat flow from the core. The heat stays further down, and the core can actually become hot enough for the solid inner core to start melting again, in a reversal of the general trend. This means that Earth's inner core is simultaneously melting and freezing, which is a pretty neat trick."

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