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. | | | CONTINUED QUIET: Solar activity remains low. Only a few sunspots are facing Earth, and none has the kind of complex magnetic field that harbors energy for strong explosions. NOAA forecasters estimate a 10% chance of M-class flares and only a 1% chance of X-flares on April 28th. Solar flare alerts: text, voice MYSTERIOUS SUN PILLAR ECHOS: Many of us have witnessed sun pillars--columns of light that lance upwards from the horizon just as the sun is rising or setting. They are caused by plate-shaped ice crystals in clouds that bend the rays of the low-hanging sun. While sun pillars are frequently seen, in all seasons and at all latitudes, elusive companions of sun pillars may have been frequently overlooked. They are called sun pillar "echos": Image credit: Jon Inghram. Larger images: #1, #2 Atmospheric optics expert Les Cowley explains: "13 years ago in Finland, three halo experts saw peculiar 'echoes' straddling an otherwise ordinary sun pillar. They could not be explained and there the matter rested for want of confirmation by another observation. Then, last week, Jon Inghram sent me several sun pillar images. He too had noticed faint 'echoes' on each side of his pillar – the mysterious ice halo was at last confirmed!" "More details and pictures may be found in an article here. But we still cannot explain them. The Finland observers, Jon and I have each tried simulations using the flattened pyramid crystals invoked to account for elliptical halos. They do not work at all well. We need many more observations! Take plenty of pictures of each pillar. The echoes are easily overlooked or mistaken for cloud patches and have probably been seen many times. Observations under different conditions could help unravel their mystery." Realtime Space Weather Photo Gallery WINGED SUNSPOT: Yesterday, for less than a second, the sunspot number surged. Kamila Mazurkiewicz of Michów, Poland, photographed the addition, which looked a lot like a spaceship: "It was the International Space Station," says Mazurkiewicz. Traveling faster than 17,000 mph, the ISS flitted across the sun in only 0.81 seconds, so quickly that Mazurkiewicz barely caught it. "The clouds parted just in time. There were storm clouds and thunder attending the transit. I squealed and jumped up when I saw the space station's silhouette." Would you like to know when the sunspot number will spike again? Space station transit predictions are available from CalSky.com. Solar flare alerts: text, voice Realtime Space Weather Photo Gallery Realtime Mars Photo Gallery 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. 27, 2014, the network reported 7 fireballs. (7 sporadics)
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 28, 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 | |