Saturday, April 05, 2008

Super-Charged 'Tsunami' Explodes Across the Sun

When you look up at the Sun -- rather, when you think of the Sun shining steadily above you -- you may go a lifetime without realizing how tremendously violent an object it is. But don't worry, NASA is there to observe the universe for us, and report back on how truly amazing a place it is out there.

Among the many NASA probes currently exploring the solar system, a pair of near-Earth satellites known collectively as the Solar TErestrial Relations Observatory (STEREO for short) are studying the Sun. Why two satellites? So they can watch the Sun in 3D of course.

Artist conception of the STEREO probes (Photo Courtesy NASA)

Launched on the shoulders of a Delta II rocket in October of 2006, STEREO is half-way through its two year mission, which has yielded some of the most spectacular images and video of the Sun to date.

Recently, NASA released video of "solar tsunami" that tore through the Suns atmosphere last year. For the story, and some very grainy, but very fascinating video,
check out the BBC's coverage.

A solar tsunami is created by cataclysmic disturbances on the surface of the Sun like coronal mass ejections and solar flares. In the wake of these events, "a pressure pulse" tears through the hot gas of the Sun's atmosphere.

These pulses, or solar tsunamis, are fast, super-charged explosions. In the 2007 event, the pulse moved across the face of the Sun in 35 minutes. That's pretty swift considering the Sun's diameter is about
100-times the diameter of Earth's, or 870,000 miles. That means the 2007 solar tsunami captured on video by STEREO was moving at a brisk 1.7 million miles per hour.

As if the speed of these pulses weren’t amazing enough, consider this. "The energy released in these explosions is phenomenal; about two billion times the annual world energy consumption," one expert told the BBC

Solar tsunamis move the same way sound does on Earth, by pressure waves in the air (gas). But since these waves are enhanced by the Sun's powerful magnetic fields, they're called magneto-acoustic waves (by very smart people that are more impressed by numbers and facts than catchy terms like "solar tsunami").

Magneto-acoustic waves on the sun, solar tsunamis, or whatever you want to call them were first detected by NASA's
Solar and Heliospheric Observatory (SOHO) about ten years ago.

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I started pound360 to channel my obsession with vitamins, running and the five senses. Eventually, I got bored focusing on all that stuff, so I came back from a one month hiatus in May of 2007 (one year after launching Pound360) and broadened my mumblings here to include all science.