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Listen to radar echoes from satellites and meteors, live on listener-supported Space Weather Radio. |
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ORIONID
METEOR SHOWER: Next weekend, Earth
will pass through a stream of debris from Halley's
Comet, source of the annual Orionid meteor shower.
Forecasters expect 25 meteors per hour when the
shower peaks on Oct. 21st. [
video]
[
full
story]
GEOMAGNETIC
STORM UNDERWAY: A G1-class geomagnetic
storm is
underway
on Oct. 13th. Reports of bright auroras have been
received from Scandinavia, Greenland, Canada and
several northern-tier US states. Colin Chatfield
sends this picture from Saskatoon, Saskatchewan:
"This is from my backyard around
5:00a.m. this morning," says Chatfield. "Never
have I seen the auroras so bright, especially from
within the city. They were astounding, with purple
visible to the naked eye."
The ongoing storm was triggered by
a knot of south-pointing magnetism from the sun.
During the early hours of Oct. 13th, the knot bumped
into Earth's magnetic field,
opening
a crack in our planet's magnetosphere. Solar
wind poured in to fuel the auroras.
More auroras are in the offing. NOAA
forecasters estimate a 40% chance of strong polar
geomagnetic storms on Oct. 14th when a solar wind
stream is expected to blow past Earth. High-latitude
sky watchers should be alert for auroras.
Aurora
alerts: text,
voice.
RADIO
STORM ON JUPITER: Two nights ago,
there was a storm on Jupiter--a radio storm.
Amateur radio astronomer Thomas Ashcraft recorded
the event using a shortwave radio telescope located
in New Mexico. Click on the dynamic spectrum (a
plot of intensity vs. frequency vs. time) to hear
the whooshing, crackling, popping sounds that emerged
from his telescope's loudspeaker:
Dynamic spectrum courtesy of Wes
Greenman, Radio Alachua Observatory
"Listen to the recording in
stereo," advises Ashcraft. "I recorded
the audio from two separate radios at 21.1 MHz and
20.9 MHz, so there is a stereo spatial effect from
the frequency drift of the emissions."
Jupiter's radio storms are caused
by natural radio lasers in the planet's magnetosphere
that sweep past Earth as Jupiter rotates. Electrical
currents flowing between Jupiter's upper atmosphere
and the volcanic moon Io can boost these emissions
to power levels easily detected by ham radio antennas
on Earth. Jovian "S-bursts" and "L-bursts"
mimic the sounds of woodpeckers, whales, and waves
crashing on the beach. Here are a few
audio
samples: S-bursts,
S-bursts
(slowed down 128:1),
L-Bursts
Now is a good time to listen to Jupiter's
radio storms. The distance between Earth and Jupiter
is decreasing as the giant planet approaches opposition
on Dec. 3rd; the closer we come to Jupiter, the
louder it gets.
NASA's
Radio Jove Project explains how to build your
own receiver.
DRACONID
METEOR OUTBURST: On Oct. 8th, more
than 2000 meteors per hour exploded across the skies
of North America and Europe. Radars in Canada and
Germany detected the outburst of Draconids, yet
sky watchers saw almost nothing. The meteors were
too dim for human vision. Nevertheless, a meteor
camera in Serbia captured visual evidence that an
outburst was underway:
These seven Draconids appeared over
the Petnica Science Center at the Institute of Physics
in Belgrade. They were the bright "tip of the
iceberg" marking the presence of an underlying
stream of much dimmer and more numerous meteoroids.
Researchers believe the outburst happened when Earth
passed through a stream of dusty debris from Comet
21P/Giacobini-Zinner, parent of the annual Draconid
meteor shower. This particular stream was laid down
by the comet when it passed by Earth's orbit in
1959.
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
October 13, 2012 there were 1337
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.
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The
official U.S. government space weather bureau |
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The
first place to look for information about sundogs,
pillars, rainbows and related phenomena. |
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Researchers
call it a "Hubble for the sun." SDO
is the most advanced solar observatory ever. |
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3D
views of the sun from NASA's Solar and Terrestrial
Relations Observatory |
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Realtime
and archival images of the Sun from SOHO. |
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from
the NOAA Space Environment Center |
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the
underlying science of space weather |
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