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EXPLOSION ON THE SUN: For days, astronomers have been monitoring a magnificent filament of magnetism stretching across the face of the sun. This morning, April 28th, it erupted. NASA's Solar Dynamics Observatory recorded the blast:
Hurled upward by magnetic instabilities, the erupting filament split the sun's atmosphere, creating a "canyon of fire." The glowing walls of the canyon trace the original channel where the filament was suspended by magnetic forces above the sun's surface. From end to end, the structure stretches more than 350,000 km--a real Grand Canyon:
A coronal mass ejection (CME) is also emerging from the blast site: SOHO image. At first glance, the CME appears to be moving well away from the sun-Earth line. However, coronagraph data are too preliminary to rule out a glancing blow to our planet in the days ahead. Stay tuned for updates. Solar flare alerts: text, voice.
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STUBBORN AURORAS: On April 27th, Earth passed through a fold in the heliospheric current sheet. This sparked a display of "stubborn auroras" around the Arctic Circle. Thomas Kast sends this picture from Vihiluoto, Finland:
"Bright summer nights are taking over," says Kast. "When I took this photo at 1:28 am, the sun was only 11o below the horizon. As you see in the photo, the aurora not only had to fight against the twilight but also the city lights of Oulu on the right and the bright Moon to its left. "
"For two more days auroras can theoretically be seen here [at latitude +65 N]," he adds.
That might not be enough time. The next display of Arctic auroras is expected three days from now when a minor CME might sideswipe Earth's magnetic field. Just how stubborn can Northern Lights be? Stay tuned. Aurora alerts: text, voice.
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VOLCANIC PLUME = COLORFUL SUNSETS: European MetOp satellites have been monitoring aerosols blasted into the atmosphere by Chile's Calbuco volcano on April 22nd. This 5-day movie shows a plume of sulfur dioxide spreading east from Chile to Brazil:
Credit: The Global Ozone Monitoring Experiment-2 (GOME-2) onboard MetOp-A and MetOp-B
The effect of this plume on Brazilian sunsets has been dramatic. Helio C. Vital of Rio de Janeiro reports: "Pushed by strong winds, aerosols from Calbuco reached Rio on April 26th and produced an spectacular display of bright unusual colors across most of the western sky during evening twilight. The red-magenta glow lasted until an hour after local sunset."
This is what he saw:
As the sun set and the twilight faded, Jupiter and the Moon over Rio were surrounded by a distinctly purple hue.
Purple is one of the telltale signs of a volcanic sunset. Fine volcanic aerosols in the stratosphere scatter blue light which, when mixed with ordinary sunset red, produces a violet hue. But purple isn't the only thing to look for, says atmospheric optics expert Les Cowley. In addition, he advises, sky watchers in Chile and Brazil should "be alert for a very bright yellow twilight arch, fine cloud structure in the arch seen through binoculars, and long diffuse rays and shadows."
Stay tuned for updates from beneath the volcanic plume.
Space Weather Photo Gallery
Comet Photo Gallery
Every night, a network
all-sky cameras scans the skies above the United
States for meteoritic fireballs. Automated software
maintained by NASA's Meteoroid Environment Office
calculates their orbits, velocity, penetration depth
in Earth's atmosphere and many other characteristics.
Daily results are presented here on Spaceweather.com.
On Apr. 28, 2015, the network reported 10 fireballs.
In this diagram of the inner solar system, all of the fireball orbits intersect at a single point--Earth. The orbits are color-coded by velocity, from slow (red) to fast (blue). [Larger image] [movies]
Potentially Hazardous Asteroids (PHAs
are space rocks larger than approximately 100m that
can come closer to Earth than 0.05 AU. None of the
known PHAs is on a collision course with our planet,
although astronomers are finding new
all the time.
April 28, 2015 there were 1575
potentially hazardous asteroids.
Notes: LD means
"Lunar Distance." 1 LD = 384,401 km, the distance
between Earth and the Moon. 1 LD also equals 0.00256
AU. MAG is the visual magnitude of the asteroid on
the date of closest approach.
official U.S. government space weather bureau
first place to look for information about sundogs,
pillars, rainbows and related phenomena.
call it a "Hubble for the sun." SDO
is the most advanced solar observatory ever.
views of the sun from NASA's Solar and Terrestrial
and archival images of the Sun from SOHO.
the NOAA Space Environment Center
underlying science of space weather