Sometimes I complain about the earthly weather, but mostly I like to post about astronomy and space events. Hope you enjoy the articles.
By: Susie77, 7:24 PM GMT on October 22, 2011
German satellite to hit Earth this weekend with up to 1.7 tons of debris
By Michael Martinez, CNN
updated 2:48 PM EST, Sat October 22, 2011
Artist rendition of the ROSAT German satellite
By: Susie77, 12:20 AM GMT on October 21, 2011
Weekend Meteor Shower
Oct. 20, 2011: Earth is about to pass through a
stream of debris from Halley's comet, source of the annual Orionid
meteor shower. Forecasters expect more than 15 meteors per hour to fly
across the sky on Saturday morning, Oct. 22nd, when the shower peaks.
Orionids are most easily seen during the dark hours before
sunrise. Twilight Orionids, however, are the most beautiful of all.
"Although this isn't the biggest meteor shower of the year, it's
definitely worth waking up for," says Bill Cooke of the NASA Meteoroid
Environment Office. "The setting is dynamite."
Orionids are framed by some of the brightest and most beautiful
constellations in the night sky. The meteors emerge from mighty Orion,
the shower's glittering namesake. From there they streak through Taurus
the Bull, the twins of Gemini, Leo the Lion, and Canis Major--home to
Sirius, the most brilliant star of all.
This year, the Moon and Mars are part of the show. They'll form two vertices of a celestial triangle
in the eastern sky on Saturday morning while the shower is most active;
Regulus is the third vertex. Blue Regulus and red Mars are both
approximately of 1st magnitude, so they are easy to see alongside the
35% crescent Moon. Many Orionids will be diving through the triangle in
the hours before dawn.
Cooke's team at the Meteoroid Environment Office will be watching for Orionids that actually hit the Moon.
Cometary debris streams like Halley's are so wide, the whole
Earth-Moon system fits inside. So when there is a meteor shower on
Earth, there's usually one on the Moon, too. Unlike Earth, however, the
Moon has no atmosphere to intercept meteoroids. Pieces of debris fall
all the way to the surface and explode where they hit. Flashes of light
caused by thermal heating of lunar rocks and moondust are so bright,
they can sometimes be seen through backyard-class telescopes.
A map of the morning sky on Saturday, Oct. 22nd at 5:30 a.m. local time, viewed facing southeast. Click to view a larger, more complete map.
"Since we began our monitoring program in 2005, our group has
detected more than 250 lunar meteors," says Cooke. "Some explode with
energies exceeding hundreds of pounds of TNT."
So far, they've seen 15 Orionids hitting the Moon--"two in 2007,
four in 2008, and nine in 2009," recalls Cooke. This year they hope to
add to the haul. About 25% of the Moon's dark terrain will be exposed
to Halley's debris stream, giving the team millions of square miles to
scan for explosions.
Watching meteoroids hit the Moon is a good way to learn about the
structure of comet debris streams and the energy of the particles
therein. It also allows Cooke and colleagues to calculate risk factors
for astronauts who, someday, will walk on the lunar surface again.
"Going outside to watch the Orionids might not be a good idea for a moonwalker," says Cooke.
But it is a good idea for the res
By: Susie77, 8:48 PM GMT on October 19, 2011
NASA Releases Visual Tour of Earth's Fires10.19.11
By: Susie77, 1:45 PM GMT on October 18, 2011
600 Mysteries in the Night Sky
Oct 18, 2011:
NASA's Fermi team recently released the second catalog of gamma-ray
sources detected by their satellite's Large Area Telescope (LAT). Of the
1873 sources found, nearly 600 are complete mysteries. No one knows
what they are.
"Fermi sees gamma rays coming from directions in the sky where
there are no obvious objects likely to produce gamma rays," says David
Thompson, Fermi Deputy Project Scientist from Goddard Space Flight
An all-sky map of gamma-ray emissions made by the Fermi Space
Telescope. Hundreds of the sources in the map are complete mysteries. [larger image]
Gamma rays are by their very nature heralds of great energy and
violence. They are a super-energetic form of light produced by sources
such as black holes and massive exploding stars. Gamma-rays are so
energetic that ordinary lenses and mirrors do not work. As a result,
gamma-ray telescopes can't always get a sharp enough focus to determine
exactly where the sources are.
For two thirds of the new catalog's sources the Fermi scientists
can, with at least reasonable certainty, locate a known gamma
ray-producing object*, such as a pulsar or blazar, in the vicinity the
gamma-rays are coming from. But the remaining third – the "mystery
sources" -- have the researchers stumped, at least for now. And they are
the most tantalizing.
Nearly 600 sources in the latest Fermi catalog are unidentified.
"Some of the mystery sources could be clouds of dark matter –
something that's never been seen before," speculates Thompson.
About 85% of the gravitational mass of the universe is dark
matter. The stuff we see makes up the rest. Dark matter is something
that pulls on things with the force of its gravity but can't be detected
in any other way. It doesn't shine – doesn't emit or scatter light –
hence the adjective "dark."
Astronomers cannot detect dark matter directly using optical or
radio telescopes. But dark matter just might shine in gamma rays.
"We've been using Fermi to search for dark matter for a long
time," says the principal investigator for the Large Area Telescope,
Peter Michelson of Stanford University.
Some researchers believe that when two dark matter antiparticles
bump into each other, they will annihilate, producing gamma rays.
Concentrated clouds of dark matter could form a gamma ray source at
specific wavelengths detectable by Fermi.
"If we see a bump in the gamma-ray spectrum -- a narrow spectral
line at high energies corresponding to the energy of the annihilating
particles – we could be the first to 'apprehend' dark matter,” says
The team plans to continue observing the mystery sources. Fermi
scans the entire sky ever three hours, and this ongoing sequence of
observations "piles up" gamma rays for the researchers to analyze. So
far, too few gamma rays have been collected from the mystery sources to
form definite conclusions.
Colliding galaxy clusters are one possible explanation for the mystery sources.
Another, less-dark possibility for some of the mystery sources is
colliding galaxy clusters. According to Michelson and Thompson, clashes
of such magnitude would generate super large scale shock waves that
would accelerate particles. Others of the sources, they say, might be
some brand new phenomenon, perhaps something involving galactic black
When all is said and done, many of the mystery sources could prove
to be familiar. "[They] will probably turn out to be members of known
source classes – things we know but haven't recognized yet, like
undiscovered pulsars, binary systems, and supernova remnants," says
"Of course we're hoping for something really exotic like dark
matter, but we have to look first at all the other options," says
Thompson. "Fermi is an ongoing mission. We'll continue to search for
answers to these puzzles and perhaps turn up even more surprises."
Will notorious dark matter finally be nabbed? Stay tuned!
By: Susie77, 4:14 PM GMT on October 13, 2011
NASA Continues Critical Survey of Antarctica's Changing Ice
By: Susie77, 6:54 PM GMT on October 10, 2011
Susie77, 8:09 PM GMT on October 04, 2011
Susie77, 4:31 PM GMT on October 04, 2011
The devastating earthquake that struck Japan this year may have rattled
the highest layer of the atmosphere even before it shook the Earth, a
discovery that one day could be used to provide warnings of giant
quakes, scientists find.
The magnitude 9.0 quake that struck off the coast of Tohoku in Japan in March ushered in what might be the world's first complex megadisaster as it unleashed a catastrophic tsunami and set off microquakes and tremors around the globe.
Scientists recently found the surface motions and tsunamis this earthquake generated also triggered waves in the sky. These waves reached all the way to the ionosphere, one of the highest layers of the Earth's atmosphere.
Draconid Meteor Shower
Draconid Meteor Outburst
Oct. 4, 2011: On October 8th Earth is going to
plow through a stream of dust from Comet 21P/Giacobini-Zinner, and the
result could be an outburst of Draconid meteors.
"We're predicting as many as 750 meteors per hour," says Bill
Cooke of NASA's Meteoroid Environment Office. "The timing of the shower
favors observers in the Middle East, north Africa and parts of Europe."
Comet 21P/Giacobini-Zinner in Nov. 1998 photographed by astronomers at Kitt Peak. [more]
Every 6.6 years Comet Giacobini-Zinner swings through the inner
solar system. With each visit, it lays down a narrow filament of dust,
over time forming a network of filaments that Earth encounters every
year in early October.
"Most years, we pass through gaps between filaments, maybe just
grazing one or two as we go by," says Cooke. "Occasionally, though, we
hit one nearly head on--and the fireworks begin."
2011 could be such a year. Forecasters at NASA and elsewhere agree
that Earth is heading for three or more filaments on October 8th.
Multiple encounters should produce a series of variable outbursts
beginning around 1600 Universal Time (noon EDT) with the strongest
activity between 1900 and 2100 UT (3:00 pm – 5:00 pm EDT).
Forecasters aren't sure how strong the display will be, mainly
because the comet had a close encounter with Jupiter in the late 1880s.
At that time, the giant planet's gravitational pull altered the comet's
orbit and introduced some uncertainty into the location of filaments it
has shed since then. Competing models place the filaments in slightly
different spots; as a result, estimated meteor rates range from dozens
to hundreds per hour.
Comet dust stream models suggest a succession of peaks in meteor rate between 1600 and 2100 UT on Oct. 9th. Click here for details. Credit: MSFC/Meteoroid Environment Office.
One respected forecaster, Paul Wiegert of the University of
Western Ontario, says the meteor rate could go as high as 1000 per hour
-- the definition of a meteor storm. It wouldn't be the first time.
Close encounters with dusty filaments produced storms of more than
10,000 Draconids per hour in 1933 and 1946 and lesser outbursts in 1985,
1998, and 2005.
Meteors from Comet Giacobini-Zinner stream out of the northern
constellation Draco--hence their name. Draconids are among the slowest
of all meteors, hitting the atmosphere at a relatively leisurely 20
km/s. The slow pace of Draconid meteors minimizes their danger to
satellites and spacecraft and makes them visually distinctive.
"A Draconid gliding leisurely across the sky is a beautiful sight," says Cooke.
Unfortunately, many of this year's Draconids will go unseen.
Draconids are faint to begin with, and this year they have to complete
with an almost-full Moon. Lunar glare will reduce the number of meteors
visible from Europe, Africa and the Middle East by 2- to 10-fold. The
situation is even worse in North America where the shower occurs in
broad daylight—completely obliterating the display.
That isn't stopping a group1 of middle school and high
school students from Bishop, California, however. They plan to observe
the shower from the stratosphere where the sky is dark even at noontime.
Black skies at high noon, photographed from a high-altitude
helium balloon on Sept. 3, 2011. Credit: Earth to Sky, a student group
located in Bishop, CA.
Led by Science@NASA's Tony Phillips, the 15 students have been
launching helium balloons to the edge of space since May of 2011. With
more than 95% of Earth’s atmosphere below the balloon, the sky above
looks almost as black as it would from a spacecraft—perfect for
"The students are going to attempt to fly one of our low-light
meteor cameras in the payload of their balloon," says Cooke. "I hope
they catch some Draconid fireballs for us to analyze. They could be the
only ones we get."
Stay tuned for results after Oct. 8th.
Author: Dr. Tony Phillips | Credit: Science@NASA
Good-bye, Polar Bears :(
Goddard Space Flight Center
ARCTIC SEA ICE CONTINUES DECLINE, HITS SECOND-LOWEST LEVEL
WASHINGTON -- Last month the extent of sea ice covering the Arctic
Ocean declined to the second-lowest extent on record. Satellite data
from NASA and the NASA-supported National Snow and Ice Data Center
(NSIDC) at the University of Colorado in Boulder showed that the
summertime sea ice cover narrowly avoided a new record low.
The Arctic ice cap grows each winter as the sun sets for several
months and shrinks each summer as the sun rises higher in the
northern sky. Each year the Arctic sea ice reaches its annual minimum
extent in September. It hit a record low in 2007.
The near-record ice-melt followed higher-than-average summer
temperatures, but without the unusual weather conditions that
contributed to the extreme melt of 2007. "Atmospheric and oceanic
conditions were not as conducive to ice loss this year, but the melt
still neared 2007 levels," said NSIDC scientist Walt Meier. "This
probably reflects loss of multiyear ice in the Beaufort and Chukchi
seas as well as other factors that are making the ice more
Joey Comiso, senior scientist at NASA's Goddard Space Flight Center in
Greenbelt, Md., said the continued low minimum sea ice levels fits
into the large-scale decline pattern that scientists have watched
unfold over the past three decades.
"The sea ice is not only declining, the pace of the decline is
becoming more drastic," Comiso said. "The older, thicker ice is
declining faster than the rest, making for a more vulnerable
perennial ice cover."
While the sea ice extent did not dip below the 2007 record, the sea
ice area as measured by the microwave radiometer on NASA's Aqua
satellite did drop slightly lower than 2007 levels for about 10 days
in early September, Comiso said. Sea ice "area" differs from extent
in that it equals the actual surface area covered by ice, while
extent includes any area where ice covers at least 15 percent of the
Arctic sea ice extent on Sept. 9, the lowest point this year, was 4.33
million square kilometers (1.67 million square miles). Averaged over
the month of September, ice extent was 4.61 million square kilometers
(1.78 million square miles). This places 2011 as the second lowest
ice extent both for the daily minimum extent and the monthly average.
Ice extent was 2.43 million square kilometers (938,000 square miles)
below the 1979 to 2000 average.
This summer's low ice extent continued the downward trend seen over
the last 30 years, which scientists attribute largely to warming
temperatures caused by climate change. Data show that Arctic sea ice
has been declining both in extent and thickness. Since 1979,
September Arctic sea ice extent has declined by 12 percent per
"The oldest and thickest ice in the Arctic continues to decline,
especially in the Beaufort Sea and the Canada Basin," NSIDC scientist
Julienne Stroeve said. "This appears to be an important driver for
the low sea ice conditions over the past few summers."
Climate models have suggested that the Arctic could lose almost all of
its summer ice cover by 2100, but in recent years, ice extent has
declined faster than the models predicted.
NASA monitors and studies changing sea ice conditions in both the
Arctic and Antarctic with a variety of spaceborne and airborne
research capabilities. This month NASA resumes Operation IceBridge, a
multi-year series of flights over sea ice and ice sheets at both
poles. This fall's campaign will be based out of Punta Arenas, Chile,
and make flights over Antarctica . NASA also continues work toward
launching ICESat-2 in 2016, which will continue its predecessor's
crucial laser altimetry observations of ice cover from space.
To see a NASA data visualization of the 2011 Arctic sea ice minimum as
measured by the Advanced Microwave Scanning Radiometer - Earth
Observing System (AMSR-E) on Aqua, visit:
Previous Entries for 2015
By: Susie77, 8:09 PM GMT on October 04, 2011
By: Susie77, 4:31 PM GMT on October 04, 2011