I’m told weather was great at Svalbard in Norway for this morning’s total solar eclipse. Completely clear skies. The solar corona, only seen during an eclipse, looks fashionably punk with a head full of beautiful, magnetically-aligned spikes.
Because the corona is a million times fainter than the blazing surface of the Sun you can’t see it in the daytime. Only during a eclipse when the moon covers our star can we finally glimpse its hidden crown.
Every day, the orbiting Solar and Heliospheric Observatory uses a coronagraph to create and artificial eclipse as seen from space. It uses an opaque disk to block the brilliant solar surface called the photosphere, so astronomers can study the corona any time without the expense, time and uncertain weather that can make eclipses on Earth so touch-and-go.
While very dilute compared to the Sun itself, the corona is extremely hot, about a 1,800,000° F. During periods of high solar activity, especially during the peak of the 11-year sunspot cycle, the corona is evenly distributed around the solar disk. In “slow” times, it stretches out in long streamers from the Sun’s equator.
The corona’s shape is determined by magnetic fields that originate from within the Sun and extend outward for some 5 million miles. I’ve been fortunate enough to stand under the moon’s shadow during several eclipses, and it’s always the highlight. The Sun’s atmosphere, threaded with delicate loops and spikes, looks electric. Alive. If you’ve never seen a total solar eclipse, make sure to put it on your bucket list.
The moon, responsible for today’s spectacle, will put on a solo encore this evening when it will be just far enough from the Sun to glimpse shortly after sunset.
This truly is a “young” moon, just 14 hours old as seen from the East Coast, 15 from the Midwest, 16 from the mountain states and 17 from the West Coast.
Use the diagram to help you find it. The moon will be just 3° high 20 minutes after sunset. You’ll need a very open, clear sky and a pair of binoculars to attempt the challenge.
Ah, the aurora. Hard to believe, but it’s been glimmering in the north for four nights in a row as seen from the northern U.S. and southern Canada. Guy Sander of Duluth spotted it at 1:15 this morning and brought his camera along for the ride.
NOAA space weather forecasters are predicting a G1 or minor geomagnetic storm for this evening before activity tapers off for the weekend. Cause? Another one of those holes in the Sun’s corona that allows subatomic particles to flow as free as the spring breeze from there to here.
Speaking of spring, the vernal equinox begins this evening at 5:45 p.m. (CDT). That’s when the Sun crosses the celestial equator moving north. Day and night are an equal 12 hours apiece across the planet except for the North Pole where the Sun will be up 24 hours now through the first day of fall. The South Pole will see their last day of 24-hour sunlight; starting tomorrow 6 months of night commence.