| BEHOLD THE SUN:
Would you like to see fiery prominences and new-cycle sunspots
with your own eyes? On sale now: Personal
Solar Telescopes. |
|
|
SPOOKY SKIES: As
Halloween approaches, the heavens are getting in the spirit of things.
A solar wind stream is buffeting Earth's magnetic field, stirring
up ghostly auroras
around the Arctic Circle. Meanwhile, Venus and the Moon are converging
for a sunset sky
show on Halloween itself. It's a boo-utiful view; don't
miss it!
COLORADO FIREBALL:
What are the odds? On Oct. 28th at 7:29 pm
Mountain Daylight Time, a random meteoroid hit Earth's atmosphere
and disintegrated with the luminosity of a full Moon. The impact,
which could've happened anywhere, took place directly above an all-sky
video camera in Guffey, Colorado.
Click
to view videos of the fireball
"I've received more than 100 eyewitness reports,"
says astronomer Chris Peterson,
who operates the camera as part of a nightly fireball monitoring
program. Combining the data at hand, he estimates that "the
meteor had a ground
path about 170 miles long and traveled from east to west at
34 km/s (76,000 mph)."
"I was lucky enough to see it myself from inside
my house through a window," adds Thomas Ashcraft. What's amazing
about that is he was located 300 miles away in New Mexico.
"It was brilliant turquoise and green and lasted more than
nine seconds." Ashcraft is an amateur radio astronomer and
his receivers picked up echoes of distant TV transmitters bouncing
off the fireball's ionized trail: listen.
Using a computer model of Earth's meteoroid environment,
Bill Cooke of the Marshall Space Flight Center calculates
that fireballs this bright come along once every five months or
so. Rarely, however, are they witnessed. About 70% of all fireballs
streak over uninhabited ocean while half appear during the day,
invisible in sunny skies. To catch one in the crosshairs of a meteor
camera on a dark albeit cloudy night is good luck indeed.
AT THE MERCY OF MARS:
Last night on Mars, the temperature at Phoenix's
arctic landing site dropped to -141 F (-96 C). The lander is equipped
with heaters to withstand such cold, but there's a problem. Winter
is coming, days are shortening, and solar panels aren't generating
enough power. This week NASA made it official:
Phoenix's days are numbered.
To conserve power, mission controllers are now shutting down some
of Phoenix's systems. First to go: a heater that kept the lander's
digging arm warm and limber. Mission controllers turned it off on
Oct. 28th, effectively disabling the arm and saving 250 watt-hours
per day. With a pair of 3D
glasses, you can peer into Phoenix's last trench:
Over the next several weeks, three more survival heaters
will be shut down, one at a time, in an effort to save energy and
extend the mission as long as possible. Keeping Phoenix's stereo
camera in action is a priority, and the camera's heater will be
second to last turned off, say planners.
The final heater shut down will be one of two that
warm the core of the spacecraft and its batteries. This would leave
one remaining survival heater to run out on its own. "At that
point, Phoenix will be at the mercy of Mars," says mission
manager Chris Lewicki of JPL. Stay tuned for (just a few more) updates.
2008
Orionid Meteor Gallery
[IMO meteor counts]
[2006 Orionids]
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