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A celestial recording at Alibaug
October 30, 2003 16:18 IST
The world's premier magnetic observatory at Alibaug, Maharashtra, recorded the geo-effect of the Coronal Mass Ejection of the 'extreme' solar flare that erupted from giant sunspot number 486, within 19 hours of its occurrence.
Dr Shobana Alex of the Indian Institute of Geomagnetism, which houses the observatory, on Wednesday said normally the S-3 class solar radiation storm reaches the earth's geomagnetic field after 32 to 40 hours.
"The solar magnetic storm of yesterday, which erupted at 11 UT (universal time), could be recorded at Alibaug within 19 hours (about 5.30 UT)," Alex said.
She said in 1859, the Colaba observatory in Mumbai, shifted to Alibaug later, had made a similar recording.
The sun was travelling at around 2125 km per second when the CME cloud left, according to NASA astronomers.
Although the particle velocity of the CME was very high, the main phase storm effect (or field) recorded by the observatory was only -300 nT (Nano Tesla) as compared to the 1859 record of -1700 nT, Alex said.
She added that although the solar flare was considered extreme by scientists, the geomagnetic effect was not as high as in 1859.
An increase in the "compressional effect" in the geomagnetic field by 80 nT was also recorded.
A solar flare is an explosion on the sun that happens when energy stored in twisted magnetic fields (usually above sunspots) is suddenly released.
Flares produce a burst of radiation across the electromagnetic spectrum, from radio wave to X-ray and gamma rays.
A space radiation happens when an explosion on the sun accelerates solar protons toward earth.
NASA scientists on Wednesday warned that communications on earth could be disrupted this week by this spectacular eruption and that it might even hamper fire-fighting efforts in California.
The explosion of gas and charged particles into space from the corona, the outermost layer of the sun's atmosphere, is not harmful to people. But it could knock out satellite communications, which some emergency crews are relying on in battling California's wildfires, its scientists said.
Similar solar events in recent years have disrupted television transmissions, GPS navigation, oil pipeline controls and even the flow of electricity along power lines.
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