Learn to photograph Northern Lights like a pro. Sign up for Peter Rosen's Aurora Photo Courses in Abisko National Park, winner of the TripAdvisor Certificate of Excellence Award 2015. | | | FLATLINING: Solar activity is so low, the sun's X-ray output barely has a pulse. NOAA forecasters estimate a 10% chance of M-class solar flares and a miniscule 1% of X-flares on July 19th. Solar flare alerts: text or voice. MOON AND MINI-MOON: Like the Moon, Venus has phases, and today it is a 19% crescent. On July 19th in Timaru, New Zealand, photographer Paul Stewart caught Venus passing by the 8% crescent Moon. They looked very much alike: "The Moon and Venus were so close together, they fit in the same field of view of my 80mm refracting telescope," says Stewart. The crescent shape of Venus will become even more pronounced in the nights ahead as the planet moves toward "inferior conjunction"--that is, almost directly between Earth and the sun. By the end of July, Venus will be a 9% crescent, as whisper-thin as the crescent Moon Stewart photographed, and by mid-August, Venus will disappear altogether, a vanishingly-thin crescent overwhelmed by the glare of the sun. Readers, even a cheap department store telescope can reveal the phases of Venus. Point your optics west after sunset and check out the "mini-Moon." Realtime Space Weather Photo Gallery NORTHERN SKY TURNS GREEN, NO AURORAS REQUIRED: There was no geomagnetic storm last night. The sky turned green anyway. Photographer Bryan Hansel recorded the phenomenon on July 18th: The green glow was barely visible to the naked eye, but a deep-sky exposure with Hansel's Nikon D800 digital camera captured it easily. This is called "airglow." Although it resembles the aurora borealis, the underlying physics is different. Airglow is caused by an assortment of chemical reactions in the upper atmosphere driven mainly by solar ultraviolet radiation; auroras, on the other hand, are ignited by gusts of solar wind. Green airglow is best photographed from extremely dark sites on nights when the Moon is new or below the horizon. It often shows up in long exposures of the Milky Way. Indeed, the Milky Way was Hansel's actual target. "I run a Milky Way Photography Workshop," he explains."The figures on the dock are three of the photographers in my group and the light is from a camera's LCD screen." Realtime Space Weather Photo Gallery Realtime Aurora Photo Gallery Realtime Sprite 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 Jul. 19, 2015, the network reported 12 fireballs. (12 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 July 19, 2015 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 | | Web-based high school science course with free enrollment | |