iPHONE VS ANDROID! Actually, it doesn't matter which phone you carry. Our cool, new app turns both smartphones into field-tested satellite trackers. Learn more. | | |
SPACE STATION RADAR ECHO: The US Air Force Space Surveillance Radar is scanning the skies above the USA for Earth-orbiting objects. Today, Sept. 19th at 16:09 UT, the International Space Station flew through the radar's primary beam, producing a strong echo. Click here to listen. Because the ISS is traveling at 17,000 mph, the echo sounds Doppler-shifted like the whistle of a moving train. The next favorable radar pass occurs on Sept. 24 at 2142 UT. Stay tuned for live ISS echoes on SpaceWeather Radio.
POLAR ERUPTION: This morning, Sept. 19th around 0200 UT, magnetic fields around the sun's north pole became unstable and erupted. NASA's Solar Dynamics Observatory recorded the action:
This was an "empty eruption"--it did not hurl a significant cloud of plasma away from the blast site. Even if it had, Earth would not be in the line of fire.
This event shows that sunspots are not required for explosions on the sun. Sunspots are rare at the sun's poles (indeed, a polar sunspot has never been observed) and there was no sunspot at the base of this eruption. Even when sunspots are absent, the solar disk is festooned with twisted, writhing magnetic filaments that can become unstable and erupt at any time. The sun's underlying magnetism drives many forms of space weather: X-ray flares, coronal mass ejections, solar tsunamis. Add spotless polar blasts to the list!
more solar images: from Greg Piepol of Rockville, Maryland; from John Stetson of Portland, Maine; from Steve Riegel of Albuquerque, New Mexico; from Wah! of Hong Kong; from Jo Dahlmans of Ulestraten, the Netherlands; from John Minnerath of Crowheart, Wyoming; from Peter Desypris of Island of Syros, Greece; from Francisco A. Rodriguez Ramirez of Cabreja Mountain Observatory, Canary Islands;
JUPITER OVER MT. WILSON: With Jupiter approaching Earth for one of the closest encounters in decades, telescopes around the world are turning toward the giant planet. Here is the view from Mt. Wilson on Sept. 18th:
The bright light in the sky is Jupiter. The blue-white scaffolding is the exoskeleton of the historic 60-inch telescope, the largest telescope in the world available for public viewing. Astrophotographer Alan Friedman was at the controls.
"I took this picture of Jupiter," says Friedman. "Mt. Wilson is a magical location where so much of modern astronomy history was written. I spent three nights observing on the 60-inch and the 16-inch--a truly magical adventure!"
Fortunately, you don't need a famous behemoth telescope for a good view of Jupiter this week. The giant planet won't be this close again until 2022, and it looks great in amateur telescopes. Point your optics toward the bright "star" in the midnight sky for an eyeful of Jupiter's moons, cloud belts and swirling storms. Science@NASA has the full story.
Sept. 2010 Northern Lights Gallery
[previous Septembers: 2009, 2008, 2007, 2006, 2005, 2004, 2002, 2001, 2000]
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 19, 2010 there were 1145 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 |
| from the National Solar Data Analysis Center |