Looking for a unique Mother's Day gift? How about Space Roses? Proceeds from the sale of these far-out blooms support student space weather research.
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LYRID METEOR SHOWER: Earth is approaching a stream of debris from Comet Thatcher, source of the annual Lyrid meteor shower. Normally, sky watchers would see 10 to 20 meteors per hour when the shower peaks on April 21-22. This year, however, visible meteor rates will be sharply reduced by the glare of the full Moon. If you can't see the Lyrids, try listening to them as meteor radar echoes on Space Weather Radio.
SUNSPOT MIRAGE: For many photographers, departing sunspot AR2529 was an irresistible target at sunset. The sunspot's heart-shaped core beamed through the rosy twilight, marking the sun for a unique shot. On April 16th in San Francisco, California, it got a little weird. "Both the sun and the sunspot were stretched and distorted as the sun sank behind the waves of the Pacific Ocean," says Mila Zinkova, who photographed the mirage:
"Notice the vertical stretching of the sunspot," says she. "It was amazing to watch how the appearance of the sun changed as sunset progressed. Here is the full video."
Atmospheric optics expert Les Cowley explains what happened: "Each sunspot on Mila's picture is a mini mirage. The California Coast is famous for its temperature inversions. Air cooled by the offshore ocean current lies beneath warm air from inland. Sunset sunlight between the layers bends and splits into three mirage images. Two sun slices descend and one upside-down one rises. Nature is not always so simple though. In the case of Mila's sunset, there were multiple small inversion layers. Each inversion layer sliced up the sun like the corrugations of a Chinese lantern. If the air were steady enough we might see that some of the heart shaped sunspots were upside down."
Today, AR2529 has left the disk of the sun. Good-bye, and thanks for all the photo-ops.
Realtime Space Weather Photo Gallery
A DASH OF GREEN IN ARCTIC TWILIGHT: Around the Arctic Circle, night is vanishing as the summer sun rises over the polar realm. This is creating a short-lived mixture of colors in the sky: aurora green and twilight blue. Aleksander Chernucho sends this picture of the phenomenon from Russia's Kola peninsula:
"I think summer vacation is about to begin," says Chernucho, "because these are the last auroras of the 2015-2016 season."
Or, maybe, the second-to-last. An incoming solar wind stream on April 24-25 could add one more dash of green to the twilight before the Arctic sun finally overwhelms the Northern Lights. Monitor the aurora gallery for last-chance sightings.
Realtime Aurora 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, 2016, the network reported 24 fireballs.
(23 sporadics, 1 April Lyrid)
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, 2016 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.
| ||Cosmic Rays in the Atmosphere |
These measurements are based on regular space weather balloon flights: learn more.
|Situation Report -- Oct. 30, 2015 ||Stratospheric Radiation (+37o N) |
|Cosmic ray levels are elevated (+6.1% above the Space Age median). The trend is flat. Cosmic ray levels have increased +0% in the past month. |
|Sept. 06: 4.14 uSv/hr (414 uRad/hr) |
|Sept. 12: 4.09 uSv/hr (409 uRad/hr) |
|Sept. 23: 4.12 uSv/hr (412 uRad/hr) |
|Sept. 25: 4.16 uSv/hr (416 uRad/hr) |
|Sept. 27: 4.13 uSv/hr (413 uRad/hr) |
|Oct. 11: 4.02 uSv/hr (402 uRad/hr) |
|Oct. 22: 4.11 uSv/hr (411 uRad/hr) |
Approximately once a week, Spaceweather.com and the students of Earth to Sky Calculus fly "space weather balloons" to the stratosphere over California. These balloons are equipped with radiation sensors that detect cosmic rays, a surprisingly "down to Earth" form of space weather. Cosmic rays can seed clouds, trigger lightning, and penetrate commercial airplanes. Our measurements show that someone flying back and forth across the continental USA, just once, can absorb as much ionizing radiation as 2 to 5 dental X-rays. For example, here is the data from a flight on Oct. 22, 2015:
Radiation levels peak at the entrance to the stratosphere in a broad region called the "Pfotzer Maximum." This peak is named after physicist George Pfotzer who discovered it using balloons and Geiger tubes in the 1930s. Radiation levels there are more than 80x sea level.
Note that the bottom of the Pfotzer Maximim is near 55,000 ft. This means that some high-flying aircraft are not far from the zone of maximum radiation. Indeed, according to the Oct 22th measurements, a plane flying at 45,000 feet is exposed to 2.79 uSv/hr. At that rate, a passenger would absorb about one dental X-ray's worth of radiation in about 5 hours.
The radiation sensors onboard our helium balloons detect X-rays and gamma-rays in the energy range 10 keV to 20 MeV. These energies span the range of medical X-ray machines and airport security scanners.
| ||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 |