DOUBLE ASTEROID FLYBY: A pair of big, near-Earth asteroids will fly by the Earth-Moon system on Sept. 14th. 2012 QG42 is a 300-meter space rock that comes from the inner asteroid belt; it will pass 2.8 million km (7.4 lunar distances) from Earth.
2012 QC8 is even bigger, about 1.1 km in diameter, hailing from the vicinity of Jupiter; it will pass about 8.7 million km (22.7 lunar distances) from Earth. Astronomers monitoring the incoming space rocks say they are glowing like 14th to 15th magnitude stars, which makes them good targets for advanced amateur telescopes. Ephemerides: 2012 QG42, 2012 QC8.
2012 QC8 is even bigger, about 1.1 km in diameter, hailing from the vicinity of Jupiter; it will pass about 8.7 million km (22.7 lunar distances) from Earth. Astronomers monitoring the incoming space rocks say they are glowing like 14th to 15th magnitude stars, which makes them good targets for advanced amateur telescopes. Ephemerides: 2012 QG42, 2012 QC8.
EXPLOSION ON JUPITER: Apparently, something hit Jupiter during the early hours of Sept. 10th (11:35 UT), igniting a ferocious fireball in the giant planet's cloudtops. Amateur astronomer Dan Peterson Racine, Wisconsin, saw it first through his Meade 12" LX200 telescope. "It was a bright white flash that lasted only 1.5 - 2 seconds," he reports. Another amateur astronomer, George Hall of Dallas, Texas, was video-recording Jupiter at the time, and he confirmed the fireball with this video screenshot:
The fireball was probably caused by a small asteroid or comet hitting Jupiter. Similar impacts were observed in June and August 2010. An analysis of those earlier events suggests that Jupiter is frequently struck by 10 meter-class asteroids--one of the hazards of orbiting near the asteroid belt and having such a strong gravitational pull.
Astronomers around the world will now begin monitoring the impact site for signs of debris--either the cindery remains of the impactor or material dredged up from beneath Jupiter's cloud tops. Some impacts do produce such debris, while others don't. Researchers aren't sure why; perhaps this event will provide some clues.
Astronomers around the world will now begin monitoring the impact site for signs of debris--either the cindery remains of the impactor or material dredged up from beneath Jupiter's cloud tops. Some impacts do produce such debris, while others don't. Researchers aren't sure why; perhaps this event will provide some clues.
SOLAR CONJUNCTION OF MERCURY: An astronomical conjunction is underway this week--but don't bother looking up because it is hidden in broad daylight. Mercury is passing only a degree and a half from the sun. Using an opaque disk to block the sun's glare, the Solar and Heliospheric Observatory (SOHO) took this picture of the close encounter on Sept. 10th:
In the weeks ahead, Mercury will move away from the sun, emerging from the glare in mid-October to assume the role of Evening Star in the western sky at sunset. Until then, it takes a coronagraph to see the comings and goings of the innermost planet. Join SOHO for a ringside seat. www.spaceweather.com
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