When is the best time to see auroras? Where is the best place to go? And how do you photograph them? These questions and more are answered in a new book, Northern Lights - a Guide, by Pal Brekke & Fredrik Broms.
SURPRISING TELECONNECTIONS: NASA's AIM spacecraft is discovering surprising "teleconnections" in Earth's atmosphere that link weather and climate across vast distances. Strange but true: The ground temperature in Indianapolis is correlated with the frequency of noctilucent clouds over Antarctica. Get the full story and a video from Science@NASA.
THE TURQUOISE FRINGE: Lunar eclipses are supposed to be red, yet when the Moon passed through Earth's amber shadow on April 15th, many observers witnessed a softly-glowing band of turquoise blue. Robert and Elisabeth Slobins send this picture of the phenomenon from Fort Myers, Florida:
The source of the turquoise is ozone. Prof. Richard Keen, an atmospheric scientist from the University of Colorado explains: "During a lunar eclipse, most of the light illuminating the Moon passes through the stratosphere, and is reddened by scattering. However, light passing through the upper stratosphere penetrates the ozone layer, which absorbs red light and actually makes the passing light ray bluer!" This can be seen, he says, as a turquoise fringe around the red.
For years, Keen has been using lunar eclipses to probe the transparency of the stratosphere. When the stratosphere is clogged with volcanic ash and other aerosols, lunar eclipses tend to be dark red. The bright orange color of the April 15th eclipse, along with the ready visibility of the turquoise fringe, suggests that the stratosphere is clear. This is a key finding for climate change models.
To see the effects of ozone on the eclipse, you have to be looking at just the right moment. Readers are invited to browse the gallery for more examples:
Eclipse Photo Gallery
CHANCE OF M-CLASS FLARES: NOAA forecasters estimate a 60% chance of M-class flares today. The most likely source may be sunspot AR2035, which produced this M1-class eruption during the late hours of April 16th:
Watch the movie again. A dark plume of plasma leaps out of the blast site, and some it it left the sun in the form of a faint, Earth-directed CME. NOAA forecasters expect the storm cloud to reach Earth on April 19th around 1800 UT, possibly sparking geomagnetic storms. High-latitude sky watchers should be alert for auroras. Solar flare alerts: text, voice
Space Weather Photo Gallery
Aurora Photo Gallery
Mars 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. 15, 2014, the network reported 13 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 17, 2014 there were 1466
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