Monday, April 23, 2007

Dimensions of the Sun

NASA releases so many great pictures that, I admit, I've become a little callus toward them. But these new pictures are AWESOME!

What's with the hype? The first batch of 3-dimensional photos of the sun taken by the STEREO spacecraft is out! You'll need 3-D glasses so if you don't have some laying around (like I do), you might want to order a batch or request a free pair for the occasion.

STEREO (Solar TErrestrial RElation Observatory) consists of two almost identical observatories. The observatories are space-based, with one observatory traveling ahead of the Earth in its orbit and one traveling behind.

This allows the observatories to view the same areas from slightly different perspectives. Using a technique called stereoscopy, the two sets of data are then combined to form 3D images.

STEREO's primary objective is to investigate coronal mass ejections (also called CMEs). CMEs are big flares on the sun like the one shown in the picture on the right.

See the bright looping structure? That's the CME. You can't see the actual sun in this picture because an occulting disk was used to block out the most intense sunlight. The white circle in the picture marks the photosphere, so the CME is about twice as big as the visible sun!

A picture may be worth a thousand words - but they can't really capture the fact that CMEs are one of the biggest explosions in our solar system and, according to NASA, approach the power in ONE BILLION hydrogen bombs!

Why do we want to study these explosions? For that I'll leave you with NASA explanation:

Why the need for STEREO?

Coronal mass ejections (CMEs), are powerful eruptions that can blow up to 10 billion tons of the Sun's atmosphere into interplanetary space. Traveling away from the Sun at speeds of approximately one million mph (1.6 million kph), CMEs can create major disturbances in the interplanetary medium and trigger severe magnetic storms when they collide with Earth's magnetosphere.

Large geomagnetic storms directed towards Earth can damage and even destroy satellites, are extremely hazardous to Astronauts when outside of the protection of the Space Shuttle performing Extra Vehicular Activities (EVAs), and they have been known to cause electrical power outages.

CMEs: a Fundamental Science Challenge

Solar ejections are the most powerful drivers of the Sun-Earth connection. Yet despite their importance, scientists don't fully understand the origin and evolution of CMEs, nor their structure or extent in interplanetary space. STEREO's unique stereoscopic images of the structure of CMEs will enable scientists to determine their fundamental nature and origin.

1 comment:

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