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mercoledì 19 aprile 2017

asteroid fly-by 2015 JO25

ASTEROID FLYBY TODAY: Approaching from the direction of the sun, mountain-sized asteroid 2015 JO25 is flying past Earth today, April 19th, approximately 1.8 million km away. NASA says there is no danger of a collision. This unusually bright space rock is about twice as reflective as the Moon. Amateur astronomers may be able to see it in backyard telescopes as a magnitude 11 speck of light during and after the flyby. Got an image? Submit it here.
SPECTACULAR CME: Old sunspot AR2644 has returned--and it is still active. On April 18th at approximately 2000 UT, the sunspot's magnetic canopy exploded and hurled a bright coronal mass ejection (CME) into space. The ESA/NASA Solar and Heliophysics Observatory caught the cloud as it raced away from the sun:

This CME will probably miss Earth. The explosion's epicenter was too far off the Sun-Earth line for a direct hit. NOAA analysts are still evaluating the possibility of a glancing blow, however, so stay tuned for updates.

More CMEs may be in the offing.  In early April this sunspot produced a series of strong M-class flares and shortwave radio blackouts on Earth. Geoeffective activity stopped only when the sunspot went into hiding on the farside of the sun. Two weeks later it's back--and so are the explosions.

Note: By longstanding tradition, sunspots that travel around the backside of the sun and re-appear are renumbered. AR2644 therefore has a new designation: AR2651.
Realtime Aurora Photo Gallery


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