FIRST QUIET, THEN UNREST: Geomagnetic activity is expected to be low for the next two days (June 27th-28th) as Earth exits a stream of solar wind. On the third day (June 29th), our planet's magnetic field could become unsettled again when a new stream of solar wind arrives. Deep-sky auroras (visible to cameras but not the naked eye) are possible later this week. Free: Aurora Alerts
EARTH-FACING SUNSPOT: Lonely sunspot AR2664 is growing and has become a target for astrophotographers. Bernard Durand sends this picture of the sunspot's primary dark core (about as wide as Earth) and surrounding maelstrom from Serbannes, France:
"I used a Daystar Quark Combo filter to take this picture," he says. It shows the red glow of solar hydrogen seething all around the sunspot.
As the sunspot has grown, it has also developed an unstable beta-gamma magnetic field that harbors energy for M-class solar flares. Any such flare today would be Earth-directed as the sunspot is directly facing our planet.
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NEW ATMOSPHERIC RADIATION RESULTS: For the past two+ years, Spaceweather.com and the students of Earth to Sky Calculus have been monitoring cosmic rays in the atmosphere above California using high-altitude space weather balloons. After more than 100 flights, they find that dose rates have increased over the Golden State by 13% since March 2015.
Now we know the same thing is happening over New England--only more so.
The Earth to Sky team has flown balloons over Maine and New Hampshire four times since 2015, most recently on June 15, 2017. Although the data are relatively sparse compared to the better-sampled west coast, the results are clear. Radiation in the stratosphere over the northeastern corner of the USA is not only stronger than California, but also intensifying much faster--a 19% increase in New England vs. 13% in California.
What's happening? Generally speaking, cosmic rays are increasing throughout the entire solar system. This is because of the sunspot cycle. The sun is currently plunging toward a deep Solar Minimum. As it descends, the sun's weakening magnetic field and flagging solar wind provides less and less shielding against high-energy particles from deep space. Every planet in the Solar System is getting an extra dose.
The difference we see between California and New England is telling us something local about Earth. After the sun's magnetosphere deflects many cosmic rays, Earth's magnetic field and atmosphere provide another line of defense. Our data show that central California is better defended by geomagnetism than New England.
Cosmic rays penetrate commercial airlines, dosing passengers and flight crews enough that pilots are classified as occupational radiation workers. Some research shows that cosmic rays can seed clouds and trigger lightning, potentially altering weather and climate. Furthermore, there are studies ( #1, #2, #3, #4) linking cosmic rays with cardiac arrhythmias in the general population.
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AURORA SURPRISE: A minor solar wind stream brushed against Earth's magnetic field on June 25th. Forecasters didn't expect much--but we were wrong. A beautiful display of auroras appeared near Bassano, Alberta:
"It was a bit of a surprise," says photographer Alan Dyer. "I positioned myself at the south shore of this prairie lake to shoot what I hoped was going to be a good display of noctilucent clouds over the water. I got a nice aurora instead!"