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They came from outer space--and you
can have one! Genuine meteorites are now on sale in the Space Weather
Store. |
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GEOMAGNETIC
STORM: A minor (Kp=5) geomagnetic
storm is
underway.
This is probably due to Earth's passage through
the wake of a CME that swept past our planet earlier
today.
Aurora alerts:
text,
phone.
SIERRA
FIREBALL DECODED: On Sunday morning,
April 22nd, just as the Lyrid meteor shower was
dying down, a spectacular fireball exploded over
California's Sierra Nevada mountain range. The loud
explosion rattled homes from central California
to Reno, Nevada, and beyond. According to Bill Cooke,
head of NASA's Meteoroid Envronment Office, the
source of the blast was a meteoroid about the size
of a minivan.
"Elizabeth Silber at Western
University has searched for infrasound signals from
the explosion," says Cooke. "Infrasound
is very low frequency sound which can travel great
distances. There were strong signals at 2 stations,
enabling a triangulation of the energy source at
37.6N, 120.5W. This is marked by a yellow flag in
the map below."
"The energy is estimated at a whopping
3.8
kilotons of TNT, so this was a big event,"
he continues. "I am not saying there was a
3.8 kiloton explosion on the ground in California.
I am saying that the meteor possessed this amount
of energy before it broke apart in the atmosphere.
[The map] shows the location of the atmospheric
breakup, not impact with the ground."
"The fact that sonic booms were heard indicates
that this meteor penetrated very low in atmosphere,
which implies a speed less than 15 km/s (33,500
mph). Assuming this value for the speed, I get a
mass for the meteor of around 70 metric tons. Hazarding
a further guess at the density of 3 grams per cubic
centimeter (solid rock), I calculate a size of about
3-4 meters, or about the size of a minivan."
"This meteor was probably not a Lyrid; without
a trajectory, I cannot rule out a Lyrid origin,
but I think it likely that it was a background or
sporadic meteor."
News and eyewitness reports: #1,
#2,
#3,
#4.
CRESCENT
MOON ALERT: When the sun goes down
tonight, step outside and look west into the twilight.
You might see something like this:
Miguel Claro photographed the crescent
moon from Almada, Portugal. "Look just below
the bridge," he points out. "You can also
see Jupiter."
The slender crescent will be beaming
through the twilight for the next few evenings.
On Tuesday, April 24th, it will glide by Venus for
a spectacular sunset conjunction. Don't miss it!
METEOR
SHOWER RECAP: According to the International
Meteor Organization, the Lyrid meteor shower
peaked
on April 22nd around 0000 UT with a maximum between
20 and 30 meteors per hour. This doesn't place the
Lyrids among the year's best showers, but many observers
were pleasantly surprised. "This year's Lyrid
shower was much better than I expected! I saw dozens
of meteors, mostly Lyrids, nice and quick ones,"
reports Monika Landy-Gyebnar, who caught this Lyrid
over the glow of her hometown Veszprem, Hungary:
The meteors were serenaded by nightingales.
"The birds arrived here about a week ago and
they were
constantly
singing, which made the observation even more
memorable!" she adds. "Imagine being out
at night, surrounded by nightingales, with a bright
Milky Way and meteors falling through our atmosphere
- a wonderful celebration of Earth Day in 2012 which
coincided with the Lyrid maximum!"
more images: from
Pete Lawrence of Selsey, West Sussex, UK;
from
Shawn Malone near Marquette, Michigan;
from
Jimmy Westlake of Stagecoach, Colorado;
from
Darren Baskill of East Sussex, UK;
from
Brian Emfinger of Ozark, Arkansas;
from
Ivan Majchrovic of Marianka, Slovakia;
from
Peter Meadows of Chelmsford, Essex, UK;
from
Ireneusz Nowak of Wroclaw, Poland;
from
Michael Noble of Alberta, Canada;
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