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: The face of the sun is peppered with spots, but none of them is actively flaring. Solar activity is low on Dec. 17th. Solar flare alerts: text, voice
SUNSET SKY SHOW: When the sun goes down tonight, step outside and face east. Jupiter and the Moon are converging for a close encounter. On Tuesday, Dec. 17th, the pair fit together inside the constellation Gemini, and on Wednesday, Dec. 18th, they'll form a set of "celestial headlights" only 5 degrees apart. Take a look. It's a beautiful way to end the day. Sky maps: Dec. 17, 18.
A NEW CRATER ON THE MOON: Most craters on the Moon were formed millions or even billions of years ago. NASA's Lunar Reconnaissance Orbiter just found one, however, that is only 9 months old. On March 17, 2013, a bright flash of light emerged from Mare Imbrium, the Sea of Rains. Researchers concluded that a small asteroid about 0.4 meters wide hit the lunar surface and exploded like 1.3 tons of TNT. Here is the crater it made:
Lunar Reconnaissance Orbiter's LROC camera photographed the crater in July when the spacecraft made a routine pass over the impact site. Subsequent analyses presented at last week's American Geophysical Union meeting linked the crater to the March 17th impact. According to the LROC photo, the crater is 18 meters (59 feet) wide. Together with the bright rays of fresh ejecta ringing the central gouge, the entire impact mark spans an area of lunar terrain half the size of an American football field.
Unlike Earth, which has an atmosphere to protect it, the airless Moon is baldly exposed to incoming asteroids. NASA's Meteoroid Environment Office monitors the lunar surface for signs of ongoing impacts. Since 2005 they have detected flashes of light from more than 300 explosions. The March 17th event was the brightest they'd ever seen, 10 times more luminous than any other lunar meteor in the history of the program. LROC's detection of a crater in Mare Imbrium provides the kind of "ground truth" measurement they need to calibrate the entire dataset.
Realtime Space Weather Photo Gallery
CHINA LANDS ON THE MOON: Move over USA and Russia. China has joined the club of nations that has landed on the Moon. On Saturday, Dec. 14th, at 9:41 p.m. Beijing local time, China's Chang’e-3 lunar lander touched down in Sinus Iridum, the Bay of Rainbows. Hours later, a lunar rover named the Jade Rabbit ("Yutu" in Mandarin Chinese) emerged for a historic mission of exploration:
Click to view more pictures from the lunar surface
The six-wheeled, 260-lb rover is equipped with a Chinese-made nuclear battery expected to last for more than 30 years. The rover also has expandable solar arrays to absorb the sun’s energy during the day and retract at night to cover and protect equipment from temperatures of minus 170 degrees Celsius. Onboard sensors include a ground-probing radar, cameras, and a soil sampler.
The United States has not performed a soft landing on the Moon since 1972 when Apollo 17 delivered astronauts Gene Cernan and Jack Schmitt to the Taurus-Littrow valley. The former USSR last did it in 1976 with the sample return mission Luna 24.
Now, after a surprising 37-year gap in lunar ground exploration, China has started making its own tracks in the moondust. Congratulations to the people of China for their successful landing and lunar ambitions.
Realtime Space Weather Photo Gallery
EDGE OF SPACE CHRISTMAS CARDS: What do you give to the sky watcher who has everything? How about a Christmas card from the Edge of Space? For only $49.95, the students of Earth to Sky Calculus will fly your holiday greeting or favorite picture to the top of Earth's atmosphere, photograph it, and return the snapshot in time for the holidays. It's a unique gift! The group has previously flown cupcakes, shoes, US presidents, ad banners and telescopes. This holiday magic is performed using suborbital helium balloons. Contact Dr. Tony Phillips for more information.
Realtime Aurora Photo Gallery
Comet ISON 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 Dec. 17, 2013, the network reported 25 fireballs.
(20 sporadics, 4 December Leonis Minorids, 1 Geminid)
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 December 17, 2013 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 |