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.
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MYSTERY IN THE OZONE LAYER: Almost 30 years after the Montreal Protocol put the brakes on ozone-depleting chemicals, one compound remains stubbornly and mysteriously abundant in the atmosphere. NASA scientists are tracking down the source and studying its effect on the ozone layer. [video]
WEEKEND ASTEROID FLYBY: This Sunday, a house-sized asteroid named "2014 RC" will fly through the Earth-Moon system almost inside the orbit of geosynchronous satellites. At closest approach, Sept. 7th at 18:18 UTC, the 20-meter-wide space rock will pass just 40,000 km over New Zealand. This diagram from NASA shows the geometry of the encounter:
There is no danger of a collision with Earth.
Asteroid 2014 RC was discovered on the night of August 31 by the Catalina Sky Survey near Tucson, Arizona, and independently detected the next night by the Pan-STARRS 1 telescope, located on the summit of Haleakalā on Maui, Hawaii. Follow-up observations quickly confirmed the orbit of 2014 RC: it comes from just beyond the orbit of Mars.
The close appproach of this space rock offers researchers an opportunity for point-blank studies of a near-Earth asteroid. Even amateur astronomers will be able to track it. Around the time of closest approach, it will brighten to magnitude +11.5 as it zips through the constellation Pisces. This means it will be invisible to the naked eye but a relatively easy target for backyard telescopes equipped with CCD cameras. [ephemeris] [3D orbit]
According to NASA, "[the orbit of 2014 RC] will bring it back to our planet's neighborhood in the future. The asteroid's future motion will be closely monitored, but no future threatening Earth encounters have been identified."
Realtime Space Weather Photo Gallery
FILAMENT ERUPTION, EARTH-DIRECTED: On Sept. 2nd, an enormous filament of dark plasma, which had been snaking across the face of the sun for days, became unstable and erupted. NASA's Solar Dynamics Observatory recorded the blast: movie #1, #2. Soon thereafter, a lopsided CME billowed away from sun:
According to NOAA analysts, the CME will deliver a glancing blow to Earth's magnetic field on Sept. 6th. This is not a particularly fast or powerful CME. Nevertheless, the coming impact could spark auroras. The last two minor CMEs that struck Earth in late August triggered beautiful displays of Northern and Southern Lights. The reason: it's aurora season. High-latitude sky watchers should prepare for Sept. 6th. Aurora alerts: text, voice
Realtime Aurora Photo Gallery
Realtime Sprite Photo Gallery
Realtime Comet 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 Sep. 5, 2014, the network reported 18 fireballs.
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 September 5, 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 |