SUBSIDING CHANCE OF FLARES: Since it exploded spectacularly on April 19th, sunspot AR2651 has calmed. The sunspot's magnetic field is decaying and, for now, it no longer poses a threat for strong flares. Free: Solar Flare Alerts
POTENT CORONAL HOLE TURNS TOWARD EARTH: A large hole in the sun's atmosphere is turning toward Earth, and it is spewing a stream of fast-moving solar wind toward our planet. NASA's Solar Dynamics Observatory photographed the giant fissure on April 21st:
This is a "coronal hole" (CH) -- a vast region where the sun's magnetic field opens up and allows solar wind to escape. Gaseous material flowing from this coronal hole is expected to reach our planet on April 23rd or 24th and could spark moderately-strong G2-class geomagnetic storms. NOAA forecasters say the odds of a magnetic storm is 75%.
We've seen this coronal hole before. On March 27th it lashed Earth's magnetic field with a fast-moving stream that ignited intense auroras around both of Earth's poles. The coronal hole is potent because it is spewing solar wind threaded with "negative polarity" magnetic fields. Such fields do a good job connecting to Earth's magnetosphere and energizing geomagnetic storms. Free: Aurora Alerts
CONTACT BINARY ASTEROID: When mountain-sized asteroid 2014 JO25 flew past Earth on April 19th, it looked like a fast-moving speck of light in backyard telescopes. NASA radars saw much more. The 70-meter antenna at Goldstone CA pinged the asteroid, illuminating it with radio energy as it passed by. The resulting images reveal a peanut-shaped asteroid that rotates about once every five hours:
"The asteroid has a contact binary structure - two lobes connected by a neck-like region," says Shantanu Naidu, a scientist from NASA's Jet Propulsion Laboratory in Pasadena, California, who led the Goldstone observations. "The largest of the asteroid's two lobes is about 2,000 feet (620 meters) across."
These images have a resolution as fine as 25 feet (7.5 meters) per pixel. Additional radar observations are being conducted at both Goldstone and Arecibo on April 20 and 21, and could provide even greater detail. Stay tuned!
Realtime Asteroid Photo Gallery
Realtime Space Weather Photo Gallery