ANOTHER HOLE IN THE SUN'S ATMOSPHERE: A new hole is opening in the sun's atmosphere, and it is spewing a stream of solar wind into space. This extreme ultraviolet image from NASA's Solar Dynamics Observatory shows the opening, which stretches more than 600,000 km from top to bottom:
Researchers call this a "coronal hole"--a region where the sun's magnetic field opens up and allows solar wind to escape. Why is the hole dark? Because much of the hot glowing gas that used to be there is gone.
Solar wind flowing from this hole is expected to reach Earth on April 20th. G1-class geomagnetic storms and high-latitude auroras are possible at that time. Sky watchers between 50o and 60o N latitude should also be alert for STEVE, which tends to appear in that latitude range during springtime geomagnetic storms. Free: Aurora Alerts
COMPLEX ICE HALO DISPLAY: Many of us have seen a sun halo--a ring around the sun caused by ice crystals in clouds. The luminous rings are usually simple circles. On March 30th, however, things got complicated. "I saw an incredibly complex ice halo," reports Matthew Cook, who sends this picture from Ann Arbor, Michigan:
In Cook's photo, we see a complete parhelic circle, a circumscribed halo, a supralateral arc, a 22-degree halo, and a pair of sundogs. "It was a great display," he says.
Complex halos like this require not just one type of ice crystal, but many, with gem-like perfection and unusually precise crystal-to-crystal alignment. Clouds that contain such a rare ensemble of ice crystals are rare--but perhaps not as rare as you might suppose. Atmospheric optics expert Les Cowley discusses the odds of seeing such a display from your own backyard.
Realtime Space Weather Photo Gallery
MOTHER'S DAY IS LESS THAN 1 MONTH AWAY: Nothing says "I Love You" like a heart-shaped pendant from the edge of space. On Dec. 31, 2017, the students of Earth to Sky Calculus flew an array of cosmic ray sensors to the stratosphere onboard a giant helium balloon. This pendant went along for the ride:
You can have it for $119.95. The students are selling these pendants as a fund-raiser for their cosmic ray monitoring program--and they make great Mother's Day gifts. All proceeds support atmospheric radiation measurements and hands-on STEM education.
Each pendant comes with a greeting card showing the jewelry in flight and telling the story of its journey to the stratosphere and back again. Mom-satisfaction guaranteed.
Far Out Gifts: Earth to Sky Store
All proceeds support hands-on STEM education