Astronomy Picture of the Day 3-18-03

NASA ^ | 3-18-03 | Robert Nemiroff and Jerry Bonnell

[petuniasevan]

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2003 March 18

Coronal Holes on the Sun
Credit: SOHO - EIT Consortium, ESA, NASA

Explanation: The ominous, dark shapes haunting the left side of the Sun are coronal holes -- low density regions extending above the surface where the solar magnetic field opens freely into interplanetary space. Studied extensively from space since the 1960s in ultraviolet and x-ray light, coronal holes are known to be the source of the high-speed solar wind, atoms and electrons which flow outward along the open magnetic field lines. During periods of low activity, coronal holes typically cover regions just above the Sun's poles. These coronal holes, however, have just moved into view near the Sun's equator, and particles escaping them have already caused notable aurora here on Earth. Coronal holes like this one may last for a few solar rotations before the magnetic fields shift and change configurations. Shown in false-color, this picture of the Sun on March 9 was made in extreme ultraviolet light by the EIT instrument on board the space-based SOHO observatory.

[petuniasevan]

SOlar and Heliospheric Observatory images are available in near-real time at the SOHO: Exploring the Sun website.

If you'd like to keep tabs on aurora conditions, or if you are a radio broadcaster, DXer, or ham operator, stop by the Spaceweather.com site. There's also lots of information on asteroids, meteor showers, eclipses, etc.

Here is what the corona looks like visually (only visible from Earth during total eclipse).

[petuniasevan]

[GodBlessRonaldReagan]

Whoa! Fantastic pic - the fury of our sun is unimaginable...

[MeekOneGOP]

Very nice, thanks . . .

[foolish-one]

Saw the Sun for the first time Saturday through a 4.5" reflector with a solar filter. Was not expecting to be impressed. I was wrong!

[Joan912]

WOW!!

[MozartLover]

Spectacular!!!

[RightWhale]

The best auroral displays in recent years were in the mid 70s. There has been nothing like that since. It was also a rabbit maximum, and there have been no rabbit maxima like that since. With the 11 year sunspot cycle, now updated to the 22 year cycle, astounding auroral displays were expected in the mid 90s, but although aurora displays were frequent, huge, swirling, sky-covering, colorful displays were nothing like the ones of the mid 70s. I don't know if the rabbit maxima and sunspot maxima are actually related, but both have that 11 year wavelength.

31.5 hours.

[Capitalism2003]

woah...

[firewalk]

Thank you for the ping

[sistergoldenhair]

Whoa! Now that's impressive.