AURORA WATCH: Northern fall has begun with a vibrant flourish of green--that is, green Northern Lights. A solar wind stream hit Earth on Sept. 21st sparking an intense, three-day display of polar auroras. Get ready for more: Another solar wind stream is due on Sept. 27th or 28th. Updates and a gallery of spectacular photos may be found at http://www.spaceweather.com.

AURORA SEASON BEGINS: For reasons not fully understood, the weeks around the autumnal equinox produce, on average, more geomagnetic storms than any other time of year. Even the mildest solar wind stream brushing against Earth can ignite auroras. Earth is inside a high-speed solar wind stream this weekend and another is due on Sept. 27th or 28th. High latitude sky watchers should be alert for Northern Lights. (Tip: Local midnight is often the best time to watch.) Visit http://www.spaceweather.com for sky maps, photos and more.

Last week in Boulder, Colorado, scientists converged on the "Living With A Star" workshop to share the latest research in solar physics. At one point, nearly 200 participants sat slack-jawed as they watched a new movie recorded by Japan's Hinode spacecraft showing a sunspot emerging from the depths of the sun. The newborn spot resembled nothing less than a swimming planet-sized trilobite. See for yourself--and find out what it means--in today's Science@NASA story.

PHOTOGENIC SUNSPOT: During the weekend new sunspot 963 emerged, and it is putting on a remarkable show for onlookers with solar telescopes. Images featured on today's edition of http://spaceweather.com include must-see footage of a fire-fountain-like eruption plus snapshots of the International Space Station (ISS) transiting the active region. The big double-sunspot is just beginning a two week journey across the face of the sun, promising many more photo-ops in the days ahead.

A big sunspot is emerging over the sun's eastern limb, posing a threat for significant solar activity. Already it has unleashed several M-class solar flares. One of the eruptions, an M3-flare on June 1st, caused a shortwave radio fadeout over Europe. Amateur astronomers with solar telescopes should keep an eye on this photogenic sunspot, while shortwave radio listeners should be alert for flare-triggered fadeouts and other propagation effects.

Visit http://spaceweather.com for photos and more information.

RADIO-ACTIVE SUNSPOT: A new sunspot is growing near the sun's eastern limb, and it is crackling with solar flares. Yesterday, one of the flares, a C1-class explosion, unleashed a radio burst heard in loudspeakers of shortwave radios across the United States. Ham radio operators may wish to point their antennas at the sun in the days ahead in case this activity continues.

Visit http://spaceweather.com to hear the sounds of this "radio-active" sunspot.

May 2, 2007: SPARKLING SUNSPOT: Sunspot 953, which emerged one week ago, has proven to be one of the most photogenic sunspots in years. For one thing, it is crackling with micro solar flares (sometimes called "Ellerman Bombs"); this makes the sunspot appear to sparkle when viewed through the eye piece of a backyard solar telescope. There's also an active magnetic filament winding outward from the sunspot's dark core. So far, no major solar flares have issued from this active region, but it's still a great show. Check http://spaceweather.com for the latest pictures and movies.

A HEXAGON ON SATURN: The Cassini spacecraft has photographed a bizarre geometrical figure encircling Saturn's north pole: a hexagon. NASA scientists say they've never seen anything like it on any other planet. Images are posted on http://spaceweather.com.

On March 19th around 0230 UT, the Moon passed in front of the Sun, producing a partial solar eclipse visible from Russia, India, China and the northern reaches of Alaska. In those places the normally-round sun will turn into a crescent and cast strangely-curved shadows on the ground. Visit the March 19th archived page on http://spaceweather.com for more information and for photographs from the eclipse zone.

NASA Science News: No human has ever witnessed a solar eclipse quite like this: NASA's STEREO-B spacecraft was about a million miles from Earth last month when it photographed the Moon passing in front of the sun. The resulting movie looks like it came from an alien solar system.

The full story is available at: http://science.nasa.gov...stereoeclipse.htm

NASA Science News: One pole of the sun is cooler than the other. That's the surprising conclusion just announced by scientists who have been analyzing data from the ESA-NASA Ulysses spacecraft.

The full story is available at: http://science.nasa.gov...coolmystery.htm

AURORA MYSTERY: Scientists have been watching and studying auroras for centuries. But if you thought everything is known about Northern Lights, you'd be wrong. One key mystery is the "auroral substorm." Sometimes, with no warning, gently shimmering pale auroras erupt in a riot of wildly-shifting colors. Why? The answer could reveal important new information about Earth's magnetosphere.

On Saturday, Feb. 17, NASA plans to launch a fleet of five satellites into Earth orbit. The name of the mission is THEMIS and its goal is to crack the mystery of the auroral substorm. Visit Spaceweather.com over the weekend for launch photos and mission updates.

Visit http://spaceweather.com for more information.

SOUTH POLE FLYBY: Today, the ESA-NASA Ulysses spacecraft is flying over uncharted territory--the mysterious South Pole of the sun.

The full story is available at NASA.

SOLAR ACTIVITY: Something on the far side of the sun exploded yesterday, hurling a bright coronal mass ejection over the sun's eastern limb. An active sunspot must be lurking just around the corner. It should appear in a few days when solar rotation carries that part of the sun into view. Stay tuned for solar activity.

Visit http://spaceweather.com for more information.

DENVER FIREBALL: A spectacular fireball streaked over Denver, Colorado, this morning. Observers described it as "brilliant, slow, twinkling, sparkly and full of rainbow colors." Contrary to some reports, it was not a Quadrantid meteor. It was the decaying body of a Russian rocket that launched the French COROT space telescope on Dec. 27th.

Links to video and a ground track may be found at http://spaceweather.com.

HOT COMET: Comet McNaught (C/2006 P1) is plunging toward the Sun. It won't hit, but at closest approach on Jan. 13th it will be much closer to the Sun than the planet Mercury. The comet will experience fierce heating and it could brighten considerably, emerging from the encounter brighter than a 1st magnitude star.

For the next few mornings, northerners can see Comet McNaught before it disappears into the Sun's glare. It's an easy target for binoculars hanging low in the eastern sky at sunrise. After Jan. 11th, only SOHO (the Solar and Heliospheric Observatory) will be able to track the comet as it angles toward the bright Sun. SOHO images are posted in near-real time on the Internet, so you can watch the comet-sun encounter and see what happens.

Visit http://spaceweather.com for observing tips and more information.