GEOMAGNETIC STORM UNDERWAY: A minor G1-class geomagnetic storm is underway on July 21st following the arrival of a slow-moving CME that left the sun on July 15th, almost a full week ago. This minor storm could set the stage for more intense activity in the days ahead when a high-speed stream of solar wind and another CME (described below) are expected to arrive on July 22nd and 23rd, respectively.Aurora alerts: SMS Text.
SOLAR TSUNAMI AND CME (UPDATED): Sunspot AR3060 exploded during the early hours of July 21st (0110 UT), producing a C5-class solar flare and a solar tsunami. The "tsunami" is the shadowy shock wave seen racing away from the blast site in this extreme ultraviolet movie from NASA's Solar Dynamics Observatory:
Soon after the explosion, the US Air Force reported a Type II solar radio burst--a natural form of radio noise produced by shock waves in the leading edge of a CME. Characteristics of the burst suggested that a CME was tearing through the sun's atmosphere at a speed of 1063 km/s (2.4 million mph).
Coronagraphs onboard the Solar and Heliospheric Observatory (SOHO) have since seen the CME:
In the movie we see a superposition of multiple CMEs. The brightest clouds at the 8 o'clock and 10 o'clock positions may be from farside eruptions. They are not heading for Earth. Of greater interest is a faint full-halo CME which emerges just before 0206 UT. That one was launched by the tsunami and is squarely inside the Earth strike zone. NOAA forecasters expect it to arrive on July 23rd, possibly sparking G2-class geomagnetic storms. Solar flare alerts: SMS Text.
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APOLLO 11 PROOF SILVER DOLLAR (COLLECTOR'S ITEM): Fifty-three years ago today, Apollo 11 astronauts were walking on the Moon. Like the original astronauts, this rare Apollo 11 silver dollar has been to space:
You can have it for $249.95. The US Mint created Apollo 11 silver dollars to celebrate the first Moon landing--but you can no longer buy them from the Mint. You can, however, get one from Earth to Sky Calculus. The coin was flown to the stratosphere onboard the students' cosmic ray research balloon.
The silver dollar is curved and reproduces the helmet of astronaut Buzz Aldrin. Reflected in Buzz's visor are Neil Armstrong, the United States flag, and the lunar lander. The opposite side of the coin shows Neil's iconic footprint on the Moon. Included is a greeting card showing the coin in flight and a certificate of authenticity.
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