~SPACE WEATHER UPDATE~
9~30~11
SUNDIVING COMET : This morning a quartet of amateur comet hunters (M. Kusiak, S. Liwo, B. Zhou and Z. Xu) independently noticed a comet in SOHO coronagraph images. The icy visitor from the icy solar system is diving toward the sun--probably a one-way trip. Kusiak expects the doomed comet to brighten to first magnitude between now and the early hours of Oct. 1st. [finder chart] [realtime images]
CHANCE OF FLARES: Sunspot 1302, quiet now for three days, still has a 'beta-gamma-delta' magnetic field that harbors energy for X-class flares. NOAA forecasters estimate a 30% chance of such eruptions today. X-flare alerts: text, voice.
SOLAR WIND BLASTS MERCURY: At a NASA teleconference yesterday, researchers working with data from the Messenger spacecraft offered new evidence that gusts of solar wind are penetrating Mercury's magnetic field and eroding material off the planet's surface. The spacecraft has actually flown through plumes of ionized sodium scoured from the surface and escaping from weak points in Mercury's magnetosphere. Click here and scroll down to "Presenter #4" for relevant data and images.
Another "scouring event" could be in the offing. The Solar and Heliospheric Observatory (SOHO) observed two farside CMEs on Sept 29th, and one of them is heading for the innermost planet:
Using observations from SOHO and the twin STEREO spacecraft, analysts at the Goddard Space Weather Lab have modeled the trajectory of these CMEs. The one on the left should hit Mercury on October 1st at 02:13 UT +/- 7 hours. Forewarned, mission scientists for the Messenger probe can be attentive to the CME's arrival and observe its effects on Mercury.
According to the CME's forecast track, the cloud will hit Venus later the same day. The ability to forecast CME impacts on other planets is a new development in space weather forecasting made possible by NASA's deployment of spacecraft around the full circumference of the sun. Stay tuned for more interplanetary forecasts here on spaceweather.com.
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Solar wind
speed: 489.0 km/sec
density: 0.9 protons/cm3
explanation | more data
Updated: Today at 1544 UT
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X-ray Solar Flares
6-hr max: B7 1349 UT Sep30
24-hr: C7 0400 UT Sep30
explanation | more data
Updated: Today at: 1500 UT
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Daily Sun: 30 Sep 11
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Sunspot 1302 has a "beta-gamma-delta" magnetic field that harbors energy for X-class solar flares. Credit: SDO/HMI
Coronal Holes: 30 Sep 11
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Solar wind flowing from this minor coronal hole should reach Earth on ~Oct. 3rd. Credit: SDO/AIA
