Astro Bob blog: Northern lights for St. Patty's Day?Space weather forecasters predict a modest chance of aurora tomorrow night and Wednesday for Canada and the northern U.S.
By: Bob King, Duluth News Tribune
Northern Lights for St. Patty's Day?
Sunspot group 1054 is putting on a nice show in sun's northern hemisphere. The "lead" spot is the one on the right. This photo was taken this morning through a small telescope and solar filter. Details: f/14 at 1/5000", ISO 100. Photo: Bob King
2010 is off to a much better start for sunspots and solar activity than 2009 when 71 percent of the days were spotless. We've only had six spotless day this year compared to 260 last year. I realize it's only mid-March but one sunspot group after another has dotted the sun for weeks now, a sight never seen in '09.
This morning I took out the telescope to take a few photos of the moderately large group numbered 1054. This group is easily observed in a small telescope equipped with a safe solar filter. 1054 has a classic appearance with a large lead sunspot and smaller "followers" bringing up the rear. The main spot is easily several times bigger than the Earth. Imagine them next to each other in space, the Earth a cool, blue marble, the other incandescent fire. Sunspots only appear dark in contrast to the sun's visible surface called the photosphere because they're several thousands of degrees cooler. Every sunspot group is a region of concentrated magnetic energy where potential fireworks like solar flares can occur.
Other forms of solar activity include coronal mass ejections (CMEs) or explosions in the sun's corona (right) that can launch enormous numbers of subatomic particles into the solar system causing rapid changes in Earth's magnetic field than can spark northern lights displays, shortwave radio fadeouts and even the disruption of electric power grids. Yesterday the sun kicked out a dandy CME the contents of which are expected to brush the Earth starting tomorrow and continuing through the 17th. Aurora forecasters with the National Oceanic and Atmospheric Administration (NOAA) predict a modest chance that the aurora will light up the sky those nights.
Since green is the most common color of the aurora, what could be more appropriate for St. Patrick's Day? Also in our favor is the fact that March is potentially the best time of year for northern lights because our planet's magnetic field is oriented to best connect with particles streaming from the sun.When all those teeny tiny electrons and protons make their way to the upper atmosphere they crash into the air molecules high overhead and excite them to glow in curtains and arcs. Rarely is so much hoohah initiated by so little.
When you're out celebrating Tuesday or Wednesday night, be alert for a green "rainbow" low in the northern sky. While you're not likely to find a pot of gold at it's end, you just might be rewarded with the sight of a long lost friend. To watch a longer animation of the CME that may affect us, click HERE. The recently-ejected material starts moving rapidly away from the sun near the end of the animation when the clock reads March 14.
The Milky Way looks like a huge kite tail flapping in the early dawn sky Monday morning. At far left is Deneb in the Northern Cross; Vega is a top and Altair to the lower right. Connect the three and you have the Summer Triangle. Details: 20mm lens at f/2.8, 30-second exposure at ISO 1600. Photo: Bob King
After a week of cloudy nights the sight of the summer sky and Milky Way were refreshing this morning. By 5:30 a.m. the Summer Triangle was easy to see above the trees while the Teapot of Sagittarius puffed steamy clouds of stars in the southeast from its spout. Beautiful.
(The CME in the animation above occurred on January 4, 2002. Images were taken by the SOHO observatory (NASA/ESA). The sun is covered by a metal mask but its outline is marked by the white circle. Animation by Windows to the Universe staff (Randy Russell).