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SUNSET SKY SHOW: When the sun goes down tonight, look west into the sunset. The slender cresent Moon is approaching Venus from below. Try to catch them before the sky fades to black. Venus and the Moon look especially beautiful when they are framed by twilight blue. [photo gallery]
INCOMING CME, STORMS POSSIBLE ON EARTH DAY: On Saturday, April 18th, a magnetic filament attached to sunspot group AR2321 erupted, producing a C5-class solar flare. NASA's Solar Dynamics Observatory watched the filament split the sun's atmosphere as it hurtled away from the blast site:
Part of the escaping filament formed the core of a faint CME, which is now heading almost directly for Earth. The cloud should reach our planet during the late hours of April 21st. In combination with a solar wind stream already en route, the impact could spark geomagnetic storms around the poles on April 22nd, Earth Day.
This is a minor CME launched by a minor C-class flare, so it is natural to expect only minor storms when the CME arrives. Indeed, that is probably what will happen. It is notable, however, that the intense geomagnetic storm of March 17, 2015, was triggered by a C-flare/CME combo only a little more intense than this one. The "St. Patrick's Day Storm" reminds us that any CME impact can produce a significant disturbance. Indeed, NOAA forecasters estimate a 65% chance of polar magnetic storms when the CME arrives. Auroras for Earth Day, anyone? Stay tuned. Aurora alerts: text, voice.
Realtime Aurora Photo Gallery
SPACE YEAST MAKES SPACE BREAD: Thought experiment: Suppose you flew a packet of baker's yeast high above Earth's surface, to the edge of space itself, and exposed the microbes to a blast of cosmic rays. Then you made some bread. How would it taste? "It is delicious," reports Eileen Weingram of Highland Lakes, NJ, who actually did the experiment:
On March 17th, during the strongest geomagnetic storm of the current solar cycle, the students of Earth to Sky Calculus flew a Space Weather Buoy to the stratosphere. Along with radiation detectors and other sensors, the payload carried packets of brewer's and baker's yeast. En route to the stratosphere, the microbes experienced temperatures as low as -63 C and cosmic ray doses 40x Earth-normal.
To support the students' research, Eileen Weingram bought a packet of the baker's yeast. "It made a huge loaf of bread," she says. "Very yummy."
If this story whets your appetite, you can bake some "space bread" of your own. Packets of yeast are still available for only $49.95. Contact Dr. Tony Phillips to place your order--and let the baking begin! All sales support high altitude balloon flights to measure the effect of solar storms on Earth's atmosphere.
Realtime Space Weather Photo Gallery
LYRID METEOR SHOWER: Earth is entering a stream of debris from Comet Thatcher, source of the annual Lyrid meteor shower. If forecasters are correct, the shower will peak on April 22-23 with 10 to 20 meteors per hour. Sky watchers are already seeing some early arrivals. Dan Bush photographed this Lyrid fireball over Albany, Missouri, before sunrise on April 20th:
"I captured an early Lyrid meteor in two of my all sky cameras," reports Bush. "This is a 1 minute image stack. The brighter streak in the east from behind the tree is the trail of an airplane."
Reports of Lyrids have also been received from Mexico and Washington state.
The Lyrid meteor shower is usually mild, and this year may be no exception. Nevertheless, these early sightings could herald a nice display. The best time to look is between about 11 pm on April 22nd and sunrise on April 23rd. [sky map]
Observing tips: Dress warmly. Bring a reclining chair, or spread a thick blanket over a flat spot of ground. Lie down and look up. Meteors can appear in any part of the sky, although their trails will tend to point back toward the constellation Lyra, from which the meteors get their name. The hours before dawn are best, because that is when Lyra is highest in the sky.
Realtime Meteor Photo Gallery
Realtime Comet Photo Gallery
Every night, a network of NASA 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. 20, 2015, the network reported 51 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 ones
all the time.
On April 20, 2015 there were 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.
| ||The official U.S. government space weather bureau |
| ||The first place to look for information about sundogs, pillars, rainbows and related phenomena. |
| ||Researchers call it a "Hubble for the sun." SDO is the most advanced solar observatory ever. |
| ||3D views of the sun from NASA's Solar and Terrestrial Relations Observatory |
| ||Realtime and archival images of the Sun from SOHO. |
| ||from the NOAA Space Environment Center |
| ||the underlying science of space weather |