...AND A TOTALLY DIFFERENT ECLIPSE: Last night, NASA's Solar Dynamics Observatory (SDO) observed an unusual event on the sun: An erupting cloud of plasma was eclipsed by a dark magnetic filament. Play the movie for a visual explanation:
The source of the explosion is a farside active region due to turn toward Earth in a few days. For now, though, the blast site lies just behind the sun's eastern limb--perfectly situated for this rare kind of eclipse. Note the filament of relatively cool dark material snaking across the sun's surface in the foreground. That filament partially blocks our view of hot plasma exploding behind it. By studying how the light of the explosion is filtered by the foreground material, SDO mission scientists might be able to learn something new about dark filaments on the sun.
PHOBOS GRUNT UPDATE: Russian Mars probe Phobos Grunt, stranded in Earth orbit since its main engines failed to fire after launch on Nov. 8th, is beginning to sink back into the atmosphere. Analysts expect re-entry to occur sometime in early to mid-January 2012. Until then, it is possible to see the doomed probe zipping brightly across the night sky. Kevin Fetter video-recorded this pass over his home in Brockville, Canada, on Dec. 8th:
In the video, Phobos Grunt was shining about as brightly as a 3rd-magnitude star, but it can get much brighter than that. Tom Smith watched it fly over Anaheim, California, during the early hours of Dec. 9th: "Phobos Grunt was brighter than the 1st-magnitude star Deneb and moving noticeably faster than the International Space Station," he reports.
Ready to see for yourself? Check SpaceWeather's online Satellite Tracker or your smartphone for Phobos Grunt flyby times.
CONGESTED INTERSECTION: Ranging in size from microscopic space dust to mountainous asteroids, trillions of meteoroids zing through the inner solar system on a daily basis. What are the odds that seven of them would cross the same point in space? Pretty good, actually. In fact, it happened just last night. Regard the following orbit diagram, then read on for an expanation:
These are the orbits of seven objects that hit Earth on the night of Dec. 8/9. NASA’s All Sky Fireball Network recorded the meteoroids as they disintegrated in the atmosphere over the United States, each one producing a bright fireball. Note how all the orbits converge on a single point--our planet.
Every night the network's cameras scan the skies over the United States, forming an inventory of what hits the atmosphere. Combining images from multiple cameras, network software rapidly calculates the basic parameters of each interloper: orbit, speed, disintegration height, and more. At the moment, cameras are located in only four states (New Mexico, Alabama, Georgia, Tennessee), but the network is expanding to provide even better coverage. Soon we'll see just how congested our intersection in space really is. Stay tuned.