Posted: 31 Dec 2009 06:00 AM PST
2009 will go down as the sun's third quietest year on record, outpaced only by 1913 and last year.
260 of the year's 365 days (72 percent) were sunspotless. 2008 saw 266 sunspotless days, while the sun had no spots on 311 of the days in 1913. It was only a very active December that kept 2009 from besting last year's mark.
Sunspot activity waves and wanes in a roughly 11-year cycle, so hitting solar minima isn't surprising. But what the numbers underscore is that we spent much of the year still in the midst of the deepest, longest solar minimum in a long time.
People keep their eyes on sunspots because their frequency and intensity is correlated with the overall level of solar activity. Changes in the sun's energy flows can seriously impact conditions on Earth and our immediate environment in space. While a particularly active sun can generate geomagnetic storms that damage satellites and electrical grid infrastructure, a sun as quiet as the one of the last few years could affect the Earth's climate, although not by much.
"If you want to understand all the drivers of Earth's atmospheric system, you have to understand how sunspots emerge and evolve," Matthias Rempel of NCAR's High Altitude Observator told Wired.com for an earlier story.
The science of sunspots is still murky, despite new supercomputer simulations and theories about their formation. The sun remains filled with surprises.
It's been an erratic year for sunwatchers. At first, it appeared that 2009 might be even quieter than 2008. 87 percent of the days in the first three months of the year were sunspotless. In May, a big solar flare, the strongest of the new cycle, appeared to augur a return to normal for the sun. Then, August was nearly sunspotless. And in the final reversal, December has been far more active than the rest of the year.
Five regions on the sun were active at once on the 22nd, as seen above. Again assuming the current sunspot holds together until Thursday, there will have been at least one spot on 22 of the month's 31 days. Is the month's surge in activity a sign of things to come?
Tony Phillips, a NASA sky watcher who made the chart above and sketched the trend line, isn't quite ready to declare the solar minimum over.
"If the trend continues exactly as shown (prediction: it won't), sunspots will become a non-stop daily occurance no later than February 2011. Blank suns would cease and solar minimum would be over," Phillips wrote on Spaceweather.com. "If the past two years have taught us anything, however, it is that the sun can be tricky and unpredictable. Stay tuned for surprises."
Image: 1. SOHO. 2. Spaceweather.com.
Posted: 30 Dec 2009 12:44 PM PST
NASA on Tuesday selected three finalists to be the agency's next cheap, robotic exploration mission. Depending on which wins, a probe will head for Venus, the moon, or a near-Earth object no later than 2018.
The latter two missions would include the return of samples, while the Venusian lander would test the planet's composition much like the Phoenix Lander did on Mars. The NASA anointing means that the teams proposing the excursions will have some money to make more detailed plans.
The winning mission will be the next in a series of explorations under the New Frontiers program. New Frontiers missions have to run under $650 million and be ready to launch relatively quickly. In this case, the final pick will be made in 2011 and will launch just seven years later.
While NASA personnel will be digging into the proposals to come up with the official decision, we'd like to know which proposal you like. Read up on the contenders, and vote in the poll afterwards.
Name: The Surface and Atmosphere Geochemical Explorer (SAGE)
Name: Origins Spectral Interpretation Resource Identification Security Regolith Explorer (Osiris-Rex)
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