Heralded as Biggest Explosion Ever
The most massive solar eruption ever recorded occurred last Monday, July 1, 2002, at 13:19 GMT (Greenwich Mean Time), or 9:19 AM Eastern Daylight Time.
This event was captured in the images here by the Solar and Heliospheric Observatory (SOHO) satellite, a joint venture of National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA).
The eruption, known as a coronal mass ejection (CME), extended more than 30 times the Earth's diameter from the Sun. (Click here for a photo comparing the relative sizes of the Earth and a smaller solar eruption.) This particular CME is called a solar prominence, a gigantic loop of expelled solar gases.
Solar prominences begin as huge clouds of relatively cool, dense plasma (ionized gases) suspended in the Sun's corona or atmosphere. If the magnetic fields of the cloud become unstable and collapse, the resultant enormous forces expel the gases beyond the Sun's surface and into the Solar System. As they travel, the gases emit characteristic frequencies of light that reveal their makeup.
This prominence emitted light in the extreme ultraviolet range (304Å wavelength), which is characteristic of ionized helium (He II) at a "relatively" cool temperature of 60,000° Kelvin, which is 60,273° Centigrade, or 108,526° Fahrenheit. The surrounding corona is typically above 1,000,000° Kelvin.
A CME blasts billions of tons of matter at millions of miles per hour into space. Luckily, the eruption was not aimed toward Earth. If these ionized particles of gas had entered our atmosphere, they would disturb the magnetosphere, disrupting radio and satellite communications, in addition to providing amazing displays of the aurora borealis.
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The image below is the SOHO satellite's tracking of the CME over the course of 90 minutes.