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.
| || |
QUIET SUN: As the one-month anniversary of the "All-Quiet Event" approaches, the sun's global X-ray output is sinking again. Solar activity is very low. Only one sunspot (AR2135) poses a threat for significant flares, but it seems reluctant to erupt. Follow the action, or lack thereof, @spaceweatherman.
THE SUPERMOON RISES: Tonight's full Moon is the biggest and brightest full Moon of the year. Astronomers call it a perigee moon; the popular term is "supermoon." Stephen Mudge photographed the bright orb rising over the Mormon temple in Brisbane, Queensland, on Aug. 10th:
Supermoons are possible because the Moon's orbit is not a circle, it is an ellipse. One side, perigee, is 50,000 km closer than the other, apogee. Today the Moon becomes full just as it reaches perigee, the point closest to Earth. The perigee supermoon you see tonight is as much as 14% closer and 30% brighter than other full Moons of the year.
Go outside at sunset, look east, and enjoy the super-moonlight!
Realtime Space Weather Photo Gallery
PERSEID METEOR UPDATE The Perseid meteor shower is underway as Earth moves into the debris stream of parent comet Swift-Tuttle. According to the International Meteor Organization, the constellation Perseus is now spitting out meteors at a rate of about 20 per hour. In a normal year, those rates would increase 4- or 5-fold as the shower reaches its peak on August 12-13. But this is no normal year. In 2014, the glare of a supermoon will interfere with Perseid visibility, capping visible meteor rates at no more than ~30 per hour.
Now for the good news: The Perseids are rich in fireballs, and many of those extra-bright meteors can be seen in spite of the lunar glare. NASA cameras recorded one such fireball last night over Tennessee:
As the movie shows, the meteor cut through the moonlight wih ease. In the past week, NASA's network of all-sky cameras has recorded nearly 100 Perseid fireballs over the USA, and more are in the offing. So, note to sky watchers: Don't be put off by the supermoon. A trip to the moonlit countryside on August 12-13 will be rewarded by a display of Perseids, albeit fewer than usual.
A good time to look on those nights might be during the hours after sunset when the Moon is still hanging low in the sky and the constellation Perseus is rising in the northeast. Such an arrangement can produce a special type of meteor called an earthgrazer. Earthgrazers emerge from the horizon and skim the top of the atmosphere above the observer, a bit like a stone skipping across the surface of a pond. An hour's watching might net no more than one or two of this special kind of meteor, but that's plenty. Earthgrazers are colorful and gracefully slow, a rare beauty that makes any meteor-watch worthwhile.
Got clouds? You can listen to the Perseids live on Space Weather Radio.
Realtime Meteor Photo Gallery
DOUBLE SPACESHIP FLYBY: On Fridy, August 8th, Europe's robotic cargo carrier, the "George Lemaitre," flew just 4 miles underneath the International Space Station. In Berlin, Germany, astrophotographer Thomas Becker recorded the close encounter:
"I caught the two spacecraft over the Wilhelm-Foerster-Observatory in Berlin," says Becker. "Bright moonlight completed the scenery."
Loaded with more than seven tons of fuel and supplies, the George Lemaitre (a.k.a. "ATV-5") is scheduled to dock with the ISS on Tuesday, Aug. 12th. Friday's preliminary flyby allowed mission controllers to test a suite of lasers and sensors that may be incorporated into the design of future European spacecraft.
George Lemaitre, the man, was a 20th century Belgian astronomer and physicist credited with proposing the theory of the expansion of the universe. ATV-5, the fifth in Europe's series of Automated Transfer Vehicles for shuttling supplies to the ISS, was named in his honor.
The duo wil be flying in tandem over the USA and Europe this weekend. Check spacweather.com's Simple Satellite Tracker for ISS-ATV-5 sighting times.
Realtime Space Weather Photo Gallery
Realtime Comet Photo Gallery
Realtime Aurora Photo Gallery
Realtime NLC 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. 10, 2014, the network reported 13 fireballs.
(7 sporadics, 6 Perseids)
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 10, 2014 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 |