Listen to radar echoes from satellites and meteors, live on listener-supported Space Weather Radio.
OF STORMS: NOAA forecasters estimate
a 55% chance of polar geomagnetic storms today,
Nov. 30th, when a coronal mass ejection (CME) is
expected to hit Earth's magnetic field. High-latitude
sky watchers should be alert for auroras. Geomagnetic
storm alerts: text,
ACTIVITY: The most active region
on the solar disk today is emerging sunspot AR1625.
It is crackling with C-class
solar flares, like this one (C4.6) recorded on Nov.
29th by NASA's Solar Dynamics Observatory:
The eruption did not hurl a CME into
space. Neither Earth nor any other planet will be
More flares could be in the offing
as AR1625 emerges in close
proximity to another active sunspot, AR1623.
If the magnetic canopies of the two sunspots intermingle,
they could reconnect
and erupt, producing something stronger than
a C-flare. Stay tuned for updates. Solar
flare alerts: text,
Space Weather Photo Gallery
RAINBOW: Usually rainbows are seen
near storm clouds. A few days ago, Geoff Chester
was riding his bike in Arlington, Virginia, when
he looked down and found one in the asphalt. "Here's
a picture from my cellphone camera," says Chester.
"You can see the rainbow arc to the right."
According to atmospheric optics expert,
this is not a rainbow, but rather a glass
bead bow. He explains: "Crews marking paint
lines on roads often scatter small glass beads onto
the paint. The glass beads retro-reflect light and
this enhances the visibility of the markings at
night. The glass beads - if sufficiently spherical
- also produce rainbows. The difference is that
the refractive index of glass is greater than that
of water and the bow is only about 21° in radius
compared to the rainbow's 42°. The glow around the
shadow of Geoff's head is an antisolar
point phenomenon - a
heigenschein - produced by refraction through
the glass spheres."
"Looks like the mystery is solved,"
adds Chester. "Although technically the trail
is closed dusk to dawn, I know of many folks who
use it as a bike commuter route after dark, especially
this time of year. The beads enhance visibility.
I got plenty of strange looks from passersby as
I was taking the pictures!"
Space Weather Photo Gallery
Aurora Photo Gallery
Eclipse Photo Gallery
Noctilucent Cloud Photo Gallery
[previous years: 2003,
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
all the time.
November 30, 2012 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.
official U.S. government space weather bureau
first place to look for information about sundogs,
pillars, rainbows and related phenomena.
call it a "Hubble for the sun." SDO
is the most advanced solar observatory ever.
views of the sun from NASA's Solar and Terrestrial
and archival images of the Sun from SOHO.
the NOAA Space Environment Center
underlying science of space weather