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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LAUNCH ALERT: NASA's Orbiting Carbon Observatory-2 will blast off from the Vandenberg Air Force Base in California on July 1st at 02:56:44 PDT (09:56:44 UTC). Because the launch occurs on a moonless night, the event could be visible to the naked eye for hundreds of miles - perhaps as far away as portions of Nevada, Arizona, and Mexico. If you see it, and photograph it, submit your images here.
SUNSPOTS AND A SPACESHIP: The sunspot number jumped for a fraction of a second this morning, June 30th, when a winged silhouette raced across the face of the sun. It was the International Space Station, and Maximilian Teodorescu of Magurele (Ilfov), Romania, captured the transit:
"The moment of transit was predicted by Calsky," says Teodorescu. "Together with my wife, I drove a few kilometers from my workplace and settled into a corn field in 30 degrees Celsius. When the moment came we both pushed our remote control buttons and got the dark silhouette of the ISS close to the freshly emerged sunspot groups AR2104 and AR2107. So for a very brief instant (0.6 seconds) there were three large sunspot groups on the Sun for us."
In New Hampshire, photographer John Stetson saw a similar transit just a few hours later. "International, indeed!" says Stetson.
The space station is gone, but sunspot AR2104 and AR2107 remain. The two active regions are crackling with minor C-class solar flares. They could, however, pose a threat for stronger eruptions as they turn toward Earth this week. NOAA forecasters estimate a 25% chance of M-class solar flares during the next 24 hours. Solar flare alerts: text, voice
Realtime Space Weather Photo Gallery
SPRITES AND GRAVITY WAVES: The sprite show continues. "Every day this week, I have been able to photograph red sprites shooting up from the tops of thunderstorms 400 miles away in Colorado, Nebraska and Kansas," reports Jan Curtis of Santa Fe, NM. On June 27th he saw something more: "At around 10:30PM MDT, gravity wave clouds developed and intensified through midnight." This snapshot shows a red sprite cutting through the green ripples:
"While I could not detect them with my unaided eyes, time lapse video revealed that the waves were moving very slowly to the northeast," says Curtis.
The waves are, literally, the ripple effect of a powerful thunderstorm on the mesosphere some 80 km above Earth's surface. From space, these waves look like a giant atmospheric bull's eye. The green hue comes from airglow, an aurora look-alike that can be seen on very dark nights from any place on Earth.
Although airglow resembles the aurora borealis, its 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 fueled by gusts of solar wind. While auroras are confined mainly to polar regions, airglow makes a luminous bubble that surrounds the entire planet.
The undulations in the airglow Curtis photographed are caused by temperature and density perturbations rippling away from the central axis of the distant thunderstorm. Speaking simplistically, those perturbations alter chemical reaction rates in the upper atmosphere, leading to more-bright or less-bright bands depending on whether the rates are boosted or diminished, respectively.
Inhabiting the upper reaches of Earth's atmosphere alongside meteors, noctilucent clouds and some auroras, sprites and mesospheric gravity waves are true space weather phenomena. Now is a good time to see them.
Realtime Comet Photo Gallery
Realtime NLC Photo Gallery
Realtime Aurora 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 Jun. 30, 2014, the network reported 24 fireballs.
( 24 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 June 30, 2014 there were 1486 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 |