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COMPLETE DESTRUCTION OF A COMET: Earlier today, a comet dove into the sun. It did not come back out again. SOHO (the Solar and Heliospheric Observatory) witnessed the disappearance:
"That was the total destruction of a 600 km/s snowball, witnessed exclusively by SOHO," says Karl Battams of the Naval Research Lab in Washington DC. "My good friend and colleague Matthew Knight estimated the comet peaked at ~mag -0.5, putting it squarely in the top ten (five?) of SOHO's brightest Kreutz sungrazers."
Kreutz sungrazers are fragments from the breakup of a single giant comet many centuries ago. They get their name from 19th century German astronomer Heinrich Kreutz, who studied them in detail. Kreutz fragments pass by the sun and disintegrate almost every day. Most, measuring less than a few meters across, are too small to see, but occasionally a bigger fragment like this one attracts attention.
SUMMERTIME AURORAS: It's not often that a flash of lightning and distant peal of thunder makes you look up and see ... green. Yet that's what happened on the night of Aug.2-3 when auroras backlit a summer thundercloud over Center, Wisconsin. Extreme weather photographer Jeremy Friebel captured the moment:
"I took the picture from cornfield around 1 am," says Friebel.
The display occurred scant hours after a solar wind stream hit Earth's magnetic field, igniting a G1-class geomagnetic storm. At high latitudes, a rare apparition of summertime auroras lit the skies of the northern hemisphere. Thunder heralded green lights over Canada, Europe, and a handful of northern-tier US States.
The odds of more auroras are waning as Earth exits the solar wind stream. NOAA forecasters say there is a 40% chance minor geomagnetic storms on August 4th. Aurora alerts: text or voice
Realtime Aurora Photo Gallery
GREEN-BLOODED BOBBLEHEAD: The 50th Anniversary of Star Trek is now. To celebrate (and to support their crowdfunded research program) the students of Earth to Sky Calculus flew the pointy-eared science officer to the stratosphere on July 24, 2016. Here he is at the apex of the flight, more than 32.2 km (112,200 ft) above Earth's surface:
You can buy this collector's item for only $129.95 in the in the Earth to Sky Store.
Proceeds from the sale support space weather research. Bobblehead Spock hitchhiked on a helium balloon payload that carried an array of X-ray/gamma-ray sensors. By launching these sensors 3 or 4 times a month, the students have shown that cosmic rays are intensifying--a trend that affects mountain climbers, air travelers, high-altitude drones, and astronauts on the International Space Station.
Realtime Space Weather Photo Gallery
Realtime Noctilucent Cloud Photo Gallery
Realtime Sprite 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 Aug. 4, 2016, the network reported 42 fireballs.
(23 sporadics, 14 Perseids, 3 Southern delta Aquariids, 2 alpha Capricornids)
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 August 4, 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 |
| ||Tobi -- Proud Supporter of Space Education! |
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