RADIO-ACTIVE SUNSPOT: Sunday in new Mexico, a startling roar issued from the loudspeaker of amateur astronomer Thomas Ashcraft's radio telescope. "It was sunspot 1057," he says. "All day long it had been producing small radio bursts around 21 MHz. Then, at 1813 UT, it let loose a big one. The burst only lasted a minute, but it saturated the radios." Click here to listen.

Photo credit: Larry Alvarez of Flower Mound, Texas

The sounds heard were a mix of Type III and Type V radio emissions. They're caused by beams of electrons shooting out of the sunspot into the sun's atmosphere overhead. Not all sunspots produce radio emissions, but AR1057 is definitely "radio-active." "I'll be listening for more bursts in the days ahead," says Ashcraft.

You can, too, using your own radio telescope. NASA's Radio JOVE program will sell you a kit and teach you how to become an amateur radio astronomer all for less than $200.

more images: from Eric Roel of Valle de Bravo, Mexico; from Phillip Jones of Frisco, Texas; from John Minnerath of Crowheart Wyoming; from Francisco A. Rodriguez of Cabreja Mountain Observatory, Canary Islands;

RADIO-ACTIVE SUNSPOT: Yesterday in new Mexico, a startling roar issued from the loudspeaker of amateur astronomer Thomas Ashcraft's radio telescope. "It was sunspot 1057," he says. "All day long it had been producing small radio bursts around 21 MHz. Then, at 1813 UT, it let loose a big one. The burst only lasted a minute, but it saturated the radios." Click here to listen.

Photo credit: Rogerio Marcon of Campinas, Brazil [details]

The sounds you just heard were a mix of Type III and Type V radio emissions. They're caused by beams of electrons shooting out of the sunspot into the sun's atmosphere overhead. Not all sunspots produce radio emissions, but AR1057 is definitely "radio-active." "I'll be listening for more bursts in the days ahead," says Ashcraft.

You can, too, using your own radio telescope. NASA's Radio JOVE program will sell you a kit and teach you how to become an amateur radio astronomer all for less than $200.

more images: from Eric Roel of Valle de Bravo, Mexico; from Phillip Jones of Frisco, Texas; from John Minnerath of Crowheart Wyoming; from Francisco A. Rodriguez of Cabreja Mountain Observatory,

SUNSPOT CONJUNCTION: On Thursday in Cape Elizabeth, Maine, astrophotographer John Stetson and his son Peter observed a very rare event--a sunspot-space station conjunction:

Photo details: 5-inch AP refractor, Baader solar filter, Luminera 2-0 camera

"We knew when to look thanks to a prediction from CalSky," says Stetson. "The International Space Station transited the solar disk in only 0.62 seconds. We managed to catch the station's silhouette just as it was passing sunspot 1057." Stetson has been photographing solar transits for years; he ranks this one as "the best yet."

As far as we know, this is the first time the ISS has been observed in conjunction with a big sunspot. Next up: How about a sunspot-space station eclipse? It is possible to anticipate such an event because CalSky shows sunspots in their transit prediction graphics. Astrophotographers, check the web site for opportunities.

more images: from Rogerio Marcon of Campinas-SP-Brasil; from Wouter Verhesen of Sittard. The Netherlands; from Alcaria Rego of Almada, Portugal; from Andy Devey of Barnsley, South Yorkshire, UK; from John C McConnell of Maghaberry Northern Ireland; from Gianfranco Meregalli of Milano Italy; from Monika Landy-Gyebnar of Veszprem, Hungary;

NASA's Wide-field Infrared Survey Explorer (WISE).

The creature designed and built WISE, NASA's Wide-field Infrared Survey Explorer, to search for "dark" objects in space like brown dwarf stars, vast dust clouds, and Earth-approaching asteroids. WISE finds them by sensing their heat in the form of infrared light most other telescopes can't pick up.

Most of the asteroids WISE is finding are in the main asteroid belt between Mars and Jupiter, but a fraction of them are different—they're the kind of Earth-approaching asteroids that send shivers all the way down a Brontosaurus' spine.

"WISE has only been in orbit for about three months, but we've already found a handful of asteroids classified as 'potentially hazardous,' including one seen in 1996 but lost until re-observed by WISE. To be named 'potentially hazardous,' an asteroid's orbit has to pass within about 5 million miles of Earth's orbit. One of our discoveries' orbit will cross Earth's orbit less than 700,000 miles away."

Above: This blink comparison shows why infrared wavelengths are so good for asteroid hunting. It's a patch of sky in the constellation Taurus photographed at two different times by the infrared Spitzer Space Telescope. The two frames are correctly aligned; the objects are moving because they are asteroids. At thermal infrared wavelengths, most of the bright objects in the plane of the solar system are space rocks. [more]

WISE tracks each potentially hazardous near-Earth object (NEO) it finds every three hours for up to 30 hours and then produces a "short track" predicting where it will be for the next few weeks. The WISE team sends all of this information to the NASA-funded Minor Planet Center in Boston. They post it on a publicly available NEO confirmation page, where scientists and amateur astronomers alike can continue to track the asteroid.

The asteroid that is thought to have wiped out the dinosaurs was big--about 6 miles or 10 km in diameter. The chances of a similar hit in modern times are almost non-existent, but that doesn't mean we're out of the woods. Smaller asteroids are fairly common, and they could do damage, too, in the rare event of impacting the Earth. As recently as 1908, for instance, an asteroid some tens of meters across exploded over Tunguska, Russia, wiping out eight hundred square miles of remote forest.

Right: The red dot in this image is the first near-Earth asteroid discovered by WISE. [full story]

"Regional damage from a small asteroid strike can be very serious indeed," says Wright. "We need to keep surveying the skies to find these NEOs and precisely measure their orbits. If we can find the really dangerous asteroids early enough, we might have time to figure out how to deal with them."

Many telescopes on Earth are already searching. Notable programs include LINEAR, the Catalina Sky Survey and others². Working together over the years they have found more than a thousand potentially hazardous asteroids.

WISE's contribution to the total will be impressive. Between now and late October, when the mission is slated to end, Wright estimates the observatory will find a hundred thousand asteroids, mostly in the main belt, and hundreds of near Earth objects.

SUNSPOT 1057: New sunspot 1057 has almost doubled in area since it first appeared yesterday. With a pair of dark cores each larger than planet Earth, the growing active region is an easy target for amateur solar telescopes:

Rogerio Marcon took the picture on March 24th from his backyard observatory in Campinas, Brazil. The swirling magnetic fields evident in the image harbor energy for C-class eruptions. The active region has already hurled one coronal mass ejection (CME, movie) into space and more could be in the offing. Stay tuned.

more images: from Monika Landy-Gyebnar of Veszprem, Hungary; from John Minnerath of Crowheart, Wyoming; from Wouter Verhesen of Sittard, The Netherlands; from Pete Lawrence of Selsey, West Sussex, UK; from Peter Paice of Belfast, Northern Ireland; from Pavol Rapavy of Observatory Rimavska Sobota, Slovakia; from John C McConnell of Maghaberry Northern Ireland;

EMERGING SUNSPOT 1057: New sunspot 1057 is big and beautiful, and it has already unleashed a coronal mass ejection (CME, movie). The cloud is not heading toward Earth but future CMEs could be as the sunspot turns to face our planet this week. Readers with solar telescopes are encouraged to monitor developments.

STARSCAPE: It's been a quiet day on the sun. But even a quiet day on a raging stellar inferno can take your breath away. Click on the image below to view a hundred billion sq. kilometers of local starscape:

Roger Marcon recorded this magnificent view on March 22nd from his backyard observatory in Campinas, Brazil. "I couldn't fit the whole thing in a single exposure," he says. "To cover the expanse, which includes sunspot 1056 on the left and a bushy magnetic filament on the right, I took ten pictures and stitched them together." His high-tech equipment: an off-the-shelf Coronado SolarMax40 filter and a 200mm (~8 inch) refracting telescope.

Forecasters of solar activity say tomorrow should be quiet, too. Sounds like a good day to photograph the sun.

SUNSPOT SPRING: After fading away for a day, sunspot 1056 has returned and it is growing rapidly. The active region does not yet pose a threat for strong flares but this could change if its expansion continues apace. Readers with solar telescopes are encouraged to monitor developments.

sunspot images: from James Kevin Ty of Manila, Philippines; from John C McConnell of Maghaberry Northern Ireland; from Peter Paice of Belfast, Northern Ireland

NORTHERN LIGHTS: Arctic sky watchers are waiting for the CME to hit. A coronal mass ejection that left the sun on March 14th should deliver a glancing blow to Earth's magnetic field sometime today. NOAA forcasters estimate a 30% chance of geomagnetic activity when the cloud arrives. Stay tuned for Northern Lights.

PROMINENCE, CONTINUED: For the second day in a row, astronomers are monitoring an enormous prominence rising over the northwestern limb of the sun. "Twenty-four hours after I first saw it, it is still alive and more monstrous (in a beautiful way) than ever," reports Alan Friedman, who sends this picture from his observatory in downtown Buffalo, New York:

Note sunspot 1054 in the lower right corner

The magnificent arch stretches more than 20 Earth-diameters from end to end. Our planet would easily fit through any of the "little" plasma gaps evident in Friedman's photo. The size of the prominence makes it an easy target for backyard solar telescopes, and many observers say it is a mesmerizing sight as it surges and seethes through the eyepiece. Monitoring is encouraged.

more images: from G. Harmon and J. Stetson of South Portland, Maine; from John Boyd of Santa Barbara, CA; from Rainer Ehlert of San Luis Potosi, Mexico; from Nick Howes using the Faulkes Telescope North in Hawaii

Current conditions

AURORA WATCH: A solar wind stream is heading for Earth, and so is a coronal mass ejection (CME). Together, they add up to a geomagnetic storm alert for March 17th and 18th. The impact of the solar wind plus CME will brighten Arctic skies already alive with Northern Lights:

INCOMING: This morning, the Solar and Heliospheric Observatory recorded a halo CME emerging from the vicinity of sunspot 1054: movie. The cloud appears to be heading toward Earth and it could spark geomagnetic storms when it arrives on or about March 17th. High-latitude sky watchers should be alert for auroras.

Current conditions

COMET TOAST: The solar system has one less comet. On March 12th, the Solar and Heliospheric Observatory (SOHO) watched as a comet plunged into the sun and disappeared. Fierce solar heating completely destroyed the icy visitor from the outer solar system. Click on the image to see the comet's last hours:   The comet was probably a member of the Kreutz sungrazer family. Named after a 19th century German astronomer who studied them in detail,Dirk Peeters.Kreutz sungrazers are fragments from the breakup of a giant comet at least 2000 years ago. Several of these fragments pass by the sun and disintegrate every day. Most are too small to see but occasionally a big fragment--like this one--attracts attention. UPDATE: Several readers have noticed that the doomed comet was actually a string of doomed comets, plural. Click here for a Youtube video posted by Kurt McNamara, and here for a sequence of labeled diagrams from Dirk Peeters.

THE MYSTERY OF PHOBOS: Something is wrong with Phobos. The martian moon looks like a solid, but it is not as dense as a rocky solid should be. Some researchers think Phobos might be riddled with vast caverns; others say it is just a "rubble pile" masquerading as a solid body. To solve the mystery, Europe's Mars Express spacecraft is making a series of close Phobos-flybys this month. High-res photos could be available as early as this Wednesday. Stay tuned!

SOLAR FILAMENTS: Today,astronomers around the world are monitoring a pair of dark magnetic filaments on the sun. Rogerio Marcon sends this composite image from his backyard observatory in Campinas, Brasil:

The largest filament, which is curling over the sun's northeastern limb, stretches at least 50,000 km from end to end. SOHO has been monitoring the plasma-filled behemoth for more than three days: movie. How long can this filament hold itself up? If it collapses and hits the stellar surface, the impact could produce a powerful Hyder flare. Readers with solar telescopes are encouraged to monitor developments.

more images: from Robert Arnold of Isle of Skye, Scotland; from Peter Paice of Belfast, Northern Ireland; from Mike Borman of Evansville, Indiana; from David Gradwell of Near Birr Ireland; from Malcolm Park of London UK; from James Kevin Ty of Manila , Philippines; from Stephen Ames of Hodgenville, KY; from Davide Cirioni of Cilavegna, Italy; from Fabio Mariuzza of Biauzzo - Italy; from Bavais Joel of Ath, Belgium; from Alan Friedman of downtown Buffalo, NY; from Brian Woosnam of North Wales UK; from Cai-Uso Wohler of Bispingen, Germany; from S. Barube and J. Stetson of S.Portland, Maine; from Greg Piepol of Rockville, Md

QUIET SUN: All the spots on the Earth-facing side of the sun are fading away. The sun is quiet and the chance of an Earth-directed solar flare this weekend is very low.

The eruption hurled a billion-ton CME away from the sun (image), but not toward Earth. The blast site is located on the sun's eastern limb where it faces away from our planet. This marks the fourth time in the past two days that a CME has billowed away from the sun without heading in our direction. Earth keeps dodging the bullet.

With solar activity on the rise, it's only a matter of time before a CME hits. And then...be alert for auroras.

Current conditions

SOLAR ERUPTIONS: The far side of the sun is alive with activity. On Feb. 28th, NASA's twin STEREO spacecraft observed one and perhaps two clouds of material blasting away from a high-latitude, site not visible from Earth. The Solar and Heliospheric Observatory (SOHO) recorded a movie of the clouds billowing over the sun's northern limb. So far, none of this activity appears to be Earth-directed.