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TROUBLE CONTACTING MARS: NASA is suspending communications with Mars rovers and orbiters this month as the Red Planet passes almost directly behind the sun. Mars is less than 2o from the sun now, and the distance will narrow to a mere 0.4o on April 17th. "The sun can easily disrupt radio transmissions during the near-alignment," explains a NASA press release.
FAST-GROWING SUNSPOT: Solar activity is low, but a fast-growing sunspot could break the spell of quiet. AR1718 has more than doubled in size during the past 48 hours as shown in this movie from the Solar Dynamics Observatory:
The magnetic field of AR1718 is rapidly changing and therefore prone to instabilities. If it criss-crosses and reconnects--bang! A solar flare could occur. Because of the sunspot's central location on the solar disk, any eruptions would be Earth-directed. NOAA forecasters estimate a 20% chance of M-class flares on April 9th. Solar flare alerts: text, voice.
Realtime Space Weather Photo Gallery
COMET ISON UPDATE: In November 2013, Comet ISON could become one of the brightest and most active comets in years when it races through the hot atmosphere of the sun. Right now, though, it is just a dim speck in the deep-freeze of space near the orbit of Jupiter. Alberto Quijano Vodniza photographed the barely-visible comet on April 7th from his private observatory in Pasto, Narino, Colombia:
Comet ISON may look underwhelming, but that is only because it is so far away, more than 400 million miles from the sun. In fact, it is already an active comet with considerable promise. Recent measurements by NASA's Swift spacecraft shows that the comet's nucleus is spewing more than 112,000 pounds (51,000 kg) of dust, or about two-thirds the mass of an unfueled space shuttle, every minute. To produce so much dust, the comet's nucleus is probably about 5 km wide. For comparison, the nucleus of bright sungrazing Comet Lovejoy, which wowed observers in 2011, was only about one-tenth as large. Comet ISON could put on quite a show when it approaches the sun later this year.
More about Comet ISON: NASA video, 3D orbit, ephemeris, light curves.
Realtime Comet Photo Gallery
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[previous years: 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2011]
Potentially Hazardous Asteroids (
PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding
new ones all the time.
On April 9, 2013 there were 1391 potentially hazardous asteroids.
Notes: LD means "Lunar Distance." 1 LD = 384,401 km, the distance between Earth and the Moon. 1 LD also equals 0.00256 AU. MAG is the visual magnitude of the asteroid on the date of closest approach. | The official U.S. government space weather bureau |
| The first place to look for information about sundogs, pillars, rainbows and related phenomena. |
| Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever. |
| 3D views of the sun from NASA's Solar and Terrestrial Relations Observatory |
| Realtime and archival images of the Sun from SOHO. |
| from the NOAA Space Environment Center |
| the underlying science of space weather |