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, 2:50 AM GMT on May 26, 2011
Artist concept of Mars Exploration Rover.
› Full image and caption
› Interactive feature
NASA has ended operational planning activities for the Mars rover Spirit
and transitioned the Mars Exploration Rover Project to a single-rover
operation focused on Spirit's still-active twin, Opportunity.
This marks the completion of one of the most successful missions of interplanetary exploration ever launched.
Spirit last communicated on March 22, 2010, as Martian winter approached
and the rover's solar-energy supply declined. The rover operated for
more than six years after landing in January 2004 for what was planned
as a three-month mission. NASA checked frequently in recent months for
possible reawakening of Spirit as solar energy available to the rover
increased during Martian spring. A series of additional re-contact
attempts ended today, designed for various possible combinations of
"Our job was to wear these rovers out exploring, to leave no unutilized
capability on the surface of Mars, and for Spirit, we have done that,"
said Mars Exploration Rover Project Manager John Callas of NASA's Jet
Propulsion Laboratory, Pasadena, Calif.
Spirit drove 4.8 miles (7.73 kilometers), more than 12 times the goal
set for the mission. The drives crossed a plain to reach a distant range
of hills that appeared as mere bumps on the horizon from the landing
site; climbed slopes up to 30 degrees as Spirit became the first robot
to summit a hill on another planet; and covered more than half a mile
(nearly a kilometer) after Spirit's right-front wheel became immobile in
2006. The rover returned more than 124,000 images. It ground the
surfaces off 15 rock targets and scoured 92 targets with a brush to
prepare the targets for inspection with spectrometers and a microscopic
"What's really important is not only how long Spirit worked or how far
Spirit drove, but also how much exploration and scientific discovery
Spirit accomplished," Callas said.
One major finding came, ironically, from dragging the inoperable
right-front wheel as the rover was driving backwards in 2007. That wheel
plowed up bright white soil. Spirit's Alpha Particle X-ray Spectrometer
and Miniature Thermal Emission Spectrometer revealed that the bright
material was nearly pure silica.
"Spirit's unexpected discovery of concentrated silica deposits was one
of the most important findings by either rover," said Steve Squyres of
Cornell University, Ithaca, N.Y., principal investigator for Spirit and
Opportunity. "It showed that there were once hot springs or steam vents
at the Spirit site, which could have provided favorable conditions for
The silica-rich soil neighbors a low plateau called Home Plate, which
was Spirit's main destination after the historic climb up Husband Hill.
"What Spirit showed us at Home Plate was that early Mars could be a
violent place, with water and hot rock interacting to make what must
have been spectacular volcanic explosions. It was a dramatically
different world than the cold, dry Mars of today," said Squyres.
The trove of data from Spirit could still yield future science
revelations. Years of analysis of some 2005 observations by the rover's
Alpha Particle X-ray Spectrometer, Miniature Thermal Emission
Spectrometer and Moessbauer Spectrometer produced a report last year
that an outcrop on Husband Hill bears a high concentration of carbonate.
This is evidence of a wet, non-acidic ancient environment that may have
been favorable for microbial life.
"What's most remarkable to me about Spirit's mission is just how
extensive her accomplishments became," said Squyres. "What we initially
conceived as a fairly simple geologic experiment on Mars ultimately
turned into humanity's first real overland expedition across another
planet. Spirit explored just as we would have, seeing a distant hill,
climbing it, and showing us the vista from the summit. And she did it in
a way that allowed everyone on Earth to be part of the adventure."
JPL, a division of the California Institute of Technology in Pasadena,
manages the Mars Exploration Rovers Opportunity and Spirit for the NASA
Science Mission Directorate, Washington. For more about the rovers, see:
http://www.nasa.gov/rovers or http://marsrovers.jpl.nasa.gov/home/index.html.
By: Susie77, 12:43 PM GMT on May 17, 2011
Unique Space Image of Alabama Tornado Tracks
May 16, 2011: NASA has released a unique
satellite image tracing the damage of a monster EF-4 tornado that tore
through Tuscaloosa, Alabama, on April 27th. It combines visible and
infrared data to reveal damage unseen in conventional photographs.
"This is the first time we've used the ASTER instrument to track
the wake of a super-outbreak of tornadoes," says NASA meteorologist Gary
Jedlovec of the Marshall Space Flight Center in Huntsville, AL.
An ASTER visible-IR image of tornado damage near Tuscaloosa, AL. [larger image]
In the picture, captured just days after the storm, pink
represents vegetation and aqua is the absence of vegetation. The tornado
ripped up everything in its path, scouring the Earth's surface with its
terrible force. The "tearing up" of vegetation makes the tornado's
track stand out as a wide swath of aqua.
"This image and others like it are helping us study the torn
landscape to determine just how huge and powerful these twisters were
and to assess the damage they inflicted," says Jedlovec.
ASTER, short for Advanced Spaceborne Thermal Emission and
Reflection Radiometer, orbits Earth onboard NASA's Terra spacecraft. Its
data products include digital elevation maps from stereo images;
surface temperatures; vegetation maps; cloud and sea ice data; and more.
Last spring the instrument helped track the movement of the oil spill in the Gulf of Mexico.
Ground survey teams have a lot to contend with. [Youtube video]
To detect the scars left by the twisters, ASTER senses the visible
and infrared energy reflected from the planet's surface. Destruction
like crushed houses, torn and snapped trees, and uprooted crops are
evident in the multi-wavelength images.
"A demolished house, debris and soil scattered on vegetated
surfaces, and damaged trees and crops all change the pattern of
reflected radiation measured by the satellite," explains Jedlovec. "We
can analyze these patterns to help storm survey teams evaluate the
Ground teams conducting field surveys of tornado damage must try
to pinpoint where the twisters touched down, how long they stayed on the
ground, and the force of their winds. But doing this from ground level
can be tricky. Some places are nearly impossible to reach by foot or
car. Also, in remote areas, damage often goes unreported, so survey
teams don't know to look there.
This is where satellites can help.
"To get an accurate picture survey teams need to look everywhere
that sustained damage – even unreported areas. Satellite sensors detect
damage in rural areas, wilderness areas, and other unpopulated areas.
Only with that knowledge can surveyors determine the true track of a
Otherwise, says Jedlovec, a twister could have flattened a single
dwelling in a remote location, killing everyone inside, and no one would
Another sample of ASTER tornado data showing three nearly-parallel tracks of destruction. [large image] [annotated composite image]
Less critical but still important are home owners' insurance
issues. To evaluate claims submitted by storm victims, insurance
companies rely on National Weather Service storm reports based on the
"Let's say you live in a remote area," says Jedlovec. "If there's
no record of a storm passing over your area, you could be out of luck."
Jedlovec and colleagues are working now to produce satellite
images of other areas ravaged by the historic outbreak of tornadoes.
"We want to help the storm victims any way we can."
Author: Dauna Coulter | Editor: Dr. Tony Phillips | Credit: Science@NASA
More InformationASTER Home PageTerra Home Page
Gary Jedlovec heads up the SPoRT (Short-term Prediction
and Research Transition) project at the Marshall Space Flight Center in
Huntsville, Alabama, a city that was spared the worst of the damage,
though an EF-5 tornado just missed it, destroying communities only a few
SPoRT personnel created the NASA images in this story
using data provided courtesy of NASA Goddard Space Flight Center, the
Land Processes Distributed Active Archive Center, Japan’s Earth Remote
Sensing Data Analysis Center, the Ministry of Economy, Trade and
Industry, along with the Japan Research Observation System Organization.
The ASTER image in this story came from an observation on
May 4, 2011 at 11:45 A.M. local time (1645 UTC), and shows the tornado
track was roughly 80.3 miles (129.2 kilometers) long and up to 1.5 miles
(2.4 kilometers) wide.
For more information on using remote sensing to track tornado damage paths, see this paper by Jedlovec.
By: Susie77, 5:06 PM GMT on May 10, 2011
AT DAWN: No coffee? No
problem. To wake up any morning this week, all
you need to do is look out the window. Mars, Jupiter,
Venus and Mercury are aligning in the eastern sky
for a spectacular dawn conjunction. Mariano Ribas
photographed the gathering on May 9th from his home
in Buenos Aires, Argentina:
"It was an awesome morning with an unforgettable
view: four planets packed in just a 7º piece of
sky," says Ribas. "The very compact Venus-Mercury-Jupiter
triangle was simply hypnotic. And Mars, below them,
was faint but still clearly visible to naked eye.
Marvelous planetary gathering, but the best is yet
Indeed, on May 11th, Venus and
Jupiter, the two brightest planets in the Solar
System, will converge to form a pair less than 1/2
degree apart. Set your alarm for Wednesday morning
and begin the day with an eye-opener--no caffeine
more images: from
Danny Ratcliffe of Deception Bay, Queensland,
Alan Dyer near San Pedro de Atacama, Chile;
M. Raþid Tuðral of Ankara, Turkiye;
By: Susie77, 9:04 PM GMT on May 09, 2011
Better Than Coffee: Planets Align in the Morning Sky
Play ScienceCast VideoJoin Mailing ListMay 9, 2011:
Have you ever woken up at the crack of dawn, shuffled to the kitchen
counter for your first cup of joe, only to discover that you're out of
This week it's not a problem, because there's something to open
your eyes even better than coffee. Four bright planets are aligning in
the morning sky.
Click on the coffee to watch a video about the Great Morning Planet Show of May 2011.
Look out any east-facing window about a half hour before sunrise.
If you have a clear view of the horizon, you'll see Mercury, Venus, Mars
and Jupiter clustered together in a patch of sky less than 10o wide. If you wanted to, you could hide them all behind your outstretched hand—but don't. The view is too good.
The best morning is May 11th, when Venus and Jupiter converge to form a tight pair only 1/2o
apart. (Now you can hide them using no more than one finger.) Venus and
Jupiter are so bright you might think you've witnessed a double
supernova beaming through the morning twilight. But, no, it's just the
two brightest planets in our own solar system.
A ScienceCast video about this event contains an animated sky map.
Keep an eye on Venus in particular. As the sun rises and the sky
fills with morning blue, the Goddess of Love does not fade away. You can
actually see Venus in broad daylight if you know where to look.
May 11th is just the beginning. Throughout the month, the quartet
of worlds will rearrange themselves on a daily basis, forming different
shapes in the pre-dawn sky.
On May 13th, for instance, Mercury, Venus and Jupiter form a
bright celestial triangle--almost equilateral. It's a geometry lesson
before breakfast. On May 20th, a new triangle will appear. This time the
vertices are Mars, Venus, and Mercury. Observing tip: Mars is not as
bright as the others. Binoculars may be required to help you find and
fully appreciate the red planet in morning twilight.
The show comes to an end on May 30th when an exquisite crescent
Moon joins the four planets for a Grand Finale--five heavenly lights
dotting the eastern sky all at once.
What a way to begin the day.
Author: Dr. Tony Phillips | Credit: Science@NASA
By: Susie77, 1:33 AM GMT on May 06, 2011
Meteors from Halley's Comet
Play ScienceCast VideoJoin Mailing ListApril 27, 2011:
Looking for an adventure? Get up in the wee hours of the morning May
6th and head out into the country, far from the city lights. You won't
be alone. The birds will be up and singing about the coming dawn, and,
of course, about the eta Aquarid meteor shower.
The eta Aquarids are best viewed from the southern hemisphere, but
there's something special about them no matter where you live: "Each
eta Aquarid meteoroid is a piece of Halley's Comet doing a kamikaze
death dive into the atmosphere," explains NASA astronomer Bill Cooke.
"Many people have never seen this famous comet, but on the morning of
May 6th they can watch bits of it leave fiery trails across the sky."
Click on the image to view a ScienceCast video about the eta Aquarid meteor shower.
A messenger from the dawn of the universe, Halley's Comet orbits
the sun once every 76 years. Each time it swings by the sun, intense
solar heat vaporizes about 6 meters of ice and rock from the nucleus.
The debris particles, about the size of sand grains, spread along the
comet's orbit, filling it with tiny meteoroids.
"Although Halley's Comet is deep in the outer solar system at the
moment and won't return to Earth until 2061, it treats us to a meteor
shower twice a year as our planet passes by the debris cloud," says
Cooke. "In May we have the eta Aquarids, and in October the Orionids."
And there is something especially significant about the 2011 eta Aquarids.
"This is your one chance this year to see meteors blaze across the sky without glaring moonlight dimming them."
A thin crescent moon will vacate the sky in the early evening,
leaving a dark canvas for the display. Early risers are in luck, as the
best viewing is an hour or two before dawn. Lie down where you can see
as wide an expanse of sky as possible to catch more meteors with your
peripheral vision. Look up into the darkness and relax.
A NASA fireball camera at the Marshall Space Flight Center
caught this eta Aquarid meteor in flight in May 2009. [movies: avi, Quicktime]
The radiant for the eta Aquarids is in the constellation Aquarius: diagram. But you don't need to look toward the radiant to see the meteors.
"Meteors can appear in any part of the sky," says Cooke. "In fact
their trails will tend to point back toward the radiant, so if you look
that way the meteor may appear somewhat stubby. They'll appear much
longer going by you than coming at you."
You won't need binoculars or a telescope to observe eta Aquarid
meteors. The naked eye's field of view is usually best for seeing
meteors, which frequently streak more than 45 degrees across the sky.
"Eta Aquarids are fast, moving at 66 km/s (148,000 mph!), and
often trace long paths across the sky, sometimes leaving glowing,
persistent trains. In the northern hemisphere, depending on your
latitude [the closer to the equator the better], you should see from 10
to 40 meteors just before dawn."
Remember to pack a reclining chair or an old blanket to lie on,
and a thermos of hot coffee would be nice. After all, you'll be up
mighty early! The spring night air may be damp and chill, so bring along
another blanket--or better yet, a big furry dog, both for warmth and
company. Golden Retrievers work nicely.
It's sure to be a memorable experience. A night breeze caressing
your cheek, the aroma of hot coffee in the predawn air, a gently rising
chorus of birdsong accompanying your own personal light show -- and your
greatest admirer by your side. It just doesn't get any better.