Added by Erik West on September 7, 2011
A sunspot erupted, causing a flare that peaked at about 6:20pm eastern time (10:20pm UTC/GMT) on Tuesday.
In a statement on its web site on Wednesday, NASA said the flare was four times stronger than an earlier flare and can cause interference with high-frequency radio communications and may even cause radio blackouts. NASA says the radio blackout can last for up to an hour.
A solar flare is a burst of radiation from a sunspot – a region of intense magnetic activity visible as dark spots on the sun. Sunspots appear to be darker than the surrounding region because they are cooler at about 2,700 deg Celsius to 4,200 deg Celsius, compared with 5,500 deg Celsius on the rest of the sun. A solar flare is an explosive event that can last several minutes to several hours and may feature a coronal mass ejection (CME). A CME can release billions of tons of matter at several million kilometres per hour.
A CME was associated with the solar flare, yet it is expected to only graze a small part of earth’s northern atmosphere. The effects of the flare may be experienced for two days between September 8 and September 10.