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STAR WARS DAY: "May the 4th be with you." Yes, May 4th is Star Wars Day. To celebrate, Spaceweather.com and the students of Earth to Sky Calculus plan to launch a neutron sensor to the stratosphere. Successfully gathering neutron data today could set the stage for an even more interesting measurement later this week if, as predicted, a geomagnetic storm breaks out. Read more about the approaching storm, below:
EARTH-DIRECTED CME: A filament of magnetism straddling the sun's southern hemisphere erupted on May 2nd (not May 3rd as was previous reported) and hurled a CME into space. Modeling by NOAA analysts suggests that the CME will reach Earth on May 6th. For storm probabilities, scroll past this movie of the expanding cloud:
Forecasters estimate a 45% chance of geomagnetic storms when the CME arrives. Bright moonlight and summer twilight will probably overwhelm any auroras around the Arctic Circle. The Antarctic Circle is much darker. Stay tuned for Southern Lights. Aurora alerts: text, voice
Aurora Photo Gallery
METEORS FROM HALLEY'S COMET: Earth is entering a diffuse stream of debris from Halley's Comet, source of the annual eta Aquarid meteor shower. Over the weekend, NASA's network of all-sky meteor cameras detected 8 eta Aquarid fireballs over the USA. This one was bright enough to see through the glare of the waxing full Moon:
The shower is expected to peak on May 5-6 when our planet passes through the heart of the debris stream. Unfortunately, not all of the eta Aquarids are fireballs. A typical meteor from Halley's Comet is about as bright as the stars of the Big Dipper--not so easy to see in the glaring moonlight.
Nevertheless, sky watchers could still see dozens of meteors. The best time to look is before before local sunrise on May 6th. Eta Aquarids are fast, moving at 66 km/s (148,000 mph), and often trace long bright paths across the sky. Set your alarm and enjoy the show.
Meteor Photo Gallery
THE NEPAL EARTHQUAKE AND SPACE WEATHER: High above Earth, more than 60 km above sea level, there is a layer of our planet's atmosphere called "the ionosphere." It is where UV radiation from the sun strips electrons away from the atoms of normal air, creating a zone of charged gas that envelopes the globe.
The ionosphere is very sensitive to solar storms. Turns out, it can be sensitive to earthquakes, too. NASA is reporting that the magnitude 7.8 earthquake in Nepal on April 25th created waves of energy that penetrated the ionosphere and disturbed the distribution of electrons. Note the wave pattern, circled, in the upper panel of this ionospheric electron density plot:
Basically, these are waves of electron density rippling from a point in the ionosphere above the epicenter of the quake. The waves were measured by a science-quality GPS receiver in Lhasa, Tibet. It took about 21 minutes for the waves to travel 400 miles between the epicenter and the GPS receiving station.
The bottom panel of the plot is a "dynamic spectrum." Note the hot spots outlined in black. They show that the ionosphere was ringing with periods of ~2 and ~8 minutes. Presumably, these "tones" are related to atmospheric pressure waves billowing up from the trembling Earth below.
The ionosphere is the stage upon which much of space weather plays out. Auroras, meteors, and noctilucent clouds all occur there. The "Ionosphere Natural Hazards Team" at JPL studies how Earth itself affects this stage via earthquakes, volcanoes and tsunamis. You can read their report about the Nepal earthquake here.
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 May. 4, 2015, the network reported 12 fireballs.
(8 sporadics, 4 eta Aquariids)
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.
May 4, 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