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Tuesday, August 03, 2004

Life on Mars Likely, Scientist Claims

DENVER, COLORADO – Those twin robots hard at work on Mars have transmitted teasing views that reinforce the prospect that microbial life may exist on the red planet.
Results from NASA’s Spirit and Opportunity rovers are being looked over by a legion of planetary experts, including a scientist who remains steadfast that his experiment in 1976 proved the presence of active microbial life in the topsoil of Mars.
"All factors necessary to constitute a habitat for life as we know it exist on current-day Mars," explained Gilbert Levin, executive officer for science at Spherix Incorporated of Beltsville, Maryland.
Levin made his remarks here Monday at the International Symposium on Optical Science and Technology, the 49th annual meeting of Society of Photo-Optical Instrumentation Engineers (SPIE).
Provocative find
Levin has a long-standing interest in time-weathered Mars and the promise of life today on that distant and dusty world.
NASA’s 1976 Viking mission to Mars was geared-up to look for possible martian life. And it was Levin’s Labeled Release experiment that made a provocative find: The presence of a highly reactive agent in the surface material of Mars.
Levin concluded in 1997 that this activity was triggered by living microorganisms lurking in the martian soil – a judgment he admits has not been generally accepted by the scientific community.
Now roll forward to 2004. Consider the findings of Spirit and Opportunity, the golf-cart sized robots wheeling over Mars at Gusev Crater and Meridiani Planum.
"Those rovers have been absolutely sensational, pouring out thousands of images. Those images have lots of information in them. And I’ve tried to deduce something in there relative to life…and I think I found a lot," Levin told SPACE.com.
Squeezed out of the soil
In perusing rover imagery, Levin reports there is clear evidence for liquid water existing under Martian environmental conditions. "The images should be reviewed against the background of surface temperatures as varying from below to above freezing reported by both Spirit and Opportunity," he explained.
Levin points to the potential for mud puddles on Mars, showing an image of clearly disturbed martian soil after rover airbags bounced across Mars’ surface. Possible standing water and sinkholes can also be seen in rover imagery, according to his analysis. In some pictures, the often-discussed "blueberries, " tiny spheres of material, disappear as if submerged underneath mud-like surroundings, he added.
Then there are tracks left by the machines as they roll across the martian terrain. Self-taken shots by the robots show what Levin said appears to be water squeezed out of the soil which then freezes into a whitish residue left in embedded tread marks.
Similarly, Levin added, are images taken by Opportunity of the results from an operation of the robot’s Rock Abrasion Tool, or RAT. The center of that particular RAT hole is largely white, possibly indicating the formation of frost since the hole was drilled, he noted.
Organisms there now?
"The evidence presented strongly indicates the presence of liquid water or moisture at the Mars Exploration Rover sites," Levin reported at the SPIE meeting. "Mars today could support many forms of terrestrial microbial life."
Other scientists are cautious to point out that the presence of water does not guarantee life. Rather, it means one crucial ingredient exists.
There is clear evidence for frost or ice on Mars, the former Viking experimenter stated. At some point of the day -- when temperatures climb above freezing -- there’s going to be moisture…"and that’s enough to support microorganisms," he said.
None of the many new findings about Mars revealed by Spirit and Opportunity, Levin concluded, conflict with, or render untenable, his long-held belief that the Viking Labeled Release experiment in 1976 detected living microorganisms in the soil of Mars.
"I contend that today you could take a great many Earth microorganisms, put them on Mars, and they’d grow," Levin said. "And I think there are organisms there now. They may have come from Earth. They may have originated on Mars. They may have come from a third place that populated both Mars and Earth."
Rocks can be kicked up from one planet by an asteroid impact, drift through space for eons, then land on the other. Other studies have shown that these rocks could potentially transport life, in a dormant phase, from one planet to the other.
Levin said that he thinks the "greatest speculation" would be to say there can be no life on Mars.
Moon used as Earth bio-shield
If indeed Mars is rife with life, care should be taken in hauling back to Earth specimens of rock and surface materials from the red planet. NASA has indicated that, next decade, robotic craft could be dispatched to gather and return to Earth select samples of Mars for detailed laboratory study.
Could those bits of Mars, perhaps laden with martian microbes, act as dangerous cargo?
As a precaution, Levin advocates a kind of bio-shield strategy for Earth – but using the Moon.
The new NASA vision to reestablish a human presence on the Moon is good timing, Levin said. "Bring samples of Mars not to Earth but to the Moon," he said. "There we would have built a scientific laboratory in which scientists could examine the samples and determine whether or not there is a hazard."

NASA Sends Mercury a MESSENGER

Despite a 24-hour delay, a NASA spacecraft bound for Mercury was successfully launched early Tuesday, the first step in a seven-year journey to the small planet.

A Boeing-built Delta 2 rocket shot the spacecraft MESSENGER off planet at 2:15:56 a.m. EDT (0615:56 GMT) on a pillar of flame above its launch pad at NASA’s Cape Canaveral Air Force Station. The on-time space shot easily made its 12-second window, with none of the delays that scrubbed a previous attempt to launch the spacecraft on Aug. 2.

“This was another great Boeing and NASA success as we bid MESSENGER farewell,” said Chuck Dovale, NASA launch director at Kennedy Space Center in Florida, after the launch.

MESSENGER, an acronym for MErcury Surface, Space ENvironment, GEochemistry, and Ranging, is the first NASA spacecraft to Mercury since Mariner 10 passed by the planet three times between 1974 and 1975.

““Mercury is very hard to get to,” explained MESSENGER science team member Ralph McNutt, from the Johns Hopkins University Applied Physics Laboratory, during the Aug. 2 launch attempt. “To get there, the MESSENGER spacecraft is about 55 percent fuel, about the same amount as the Cassini spacecraft to Saturn.”

MESSENGER is also expected to provide some hints to questions about Mercury’s density, interior and exterior composition, as well as its surface features and magnetic field. The spacecraft is taking a roundabout path to Mercury, swinging by three inner planets before entering orbit around Mercury in March 2011.

There were some weather concerns prior to MESSENGER’s liftoff. Nearby cloud cover, and the failure of launch weather balloons to reach high into the atmosphere gave launch planners some concern. But the clouds dissipated and one last batch of weather balloons reached their designated height of 90,000 feet before launch.

A good start

Cape Canveral launch officials applauded as MESSENGER’s Delta 2 booster sent the spacecraft on its way.

Four minutes into the flight, the spacecraft-rocket combo shed its first stage and ignited its second stage for a four-minute burn to reach orbit. After a 37-minute coast phase, MESSENGER’s Delta 2 booster again fired its second stage for a three-minute burn. The spacecraft’s third stage also made a short, two-minute maneuver before MESSENGER separated from its rocket and began its trip to Mercury about 59 minutes after launch.

MESSENGER then loosed its two solar panels to generate power and switched off its batteries. The event marked the end of the first leg of MESSENGER’s five billion-mile journey to Mercury. Over the next seven years, the spacecraft will swing by the Earth once, Venus twice and Mercury three times before reaching a final orbit around the small planet.

After a year of science observations, the spacecraft will have completed its primary mission.

“The mission ends with a whimper,” McNutt said, adding MESSENGER’s fuel tanks were budgeted to provide enough propellant for a single year around Mercury. “By about 2015 or 2016, gravity will crash [MESSENGER] into the surface of the planet.”

Dovale said NASA’s next science spacecraft launch will come on Oct. 7, when the agency will launch the Swift Gamma Ray Burst Explorer atop a Boeing Delta 2 in a space shot to be staged from Cape Canaveral Air Force Station.

today picture:Opportunity: Me and My Shadow

This self-portrait of NASA's Mars Exploration Rover Opportunity comes courtesy of the Sun and the rover's front hazard-avoidance camera. The dramatic snapshot of Opportunity's shadow was taken as the rover continues to move farther into "Endurance Crater." The image was taken on July 26, 2004, the date when the rover fully doubled its primary mission.

Scientists' Showdown With Soil Moisture At The O.K. Corral

from nasa newsletter

Alan Buis (818) 354-5011Jet Propulsion Laboratory, Pasadena, Calif.
Gretchen Cook-Anderson (202) 358-0836NASA Headquarters, Washington
Sandy Miller Hays (301) 504-1638USDA Agricultural Research Service, Washington
News Release: 2004-188 August 2, 2004 Scientists' Showdown With Soil Moisture At The O.K. Corral
Tombstone, Ariz., is a dusty place known for Wyatt Earp's famous 1881 "Shootout at the O.K. Corral." This year, from August 2 to 27, it will be known as the place where scientists from NASA, the U.S. Department of Agriculture, the National Oceanic and Atmospheric Administration, and other institutions gather and study soil moisture to improve weather forecasts and the ability to interpret satellite data.
By identifying how much moisture is retained in soils, hydrologists will be able to determine how much more water can be absorbed, and thus better estimate the potential for flooding, or the amount of water that can sink into the water table. During July and August, the U.S. Southwestern monsoon season is characterized by a wind pattern shift that exerts a strong influence on precipitation and temperatures across the Western United States, Mexico and adjacent ocean areas. This change in winds over the region creates many rainy days and heavy rainfall, which are ideal conditions for studying soil moisture.
The study, called the Soil Moisture Experiment 2004, will use ground teams, airplanes and NASA satellites and instruments to measure soil moisture in Tombstone and Sonora, Mexico, where water supplies are critical.
Researchers from NASA, the U.S. Department of Agriculture, the National Oceanic and Atmospheric Administration, Sonora Research Institute and more than a dozen universities will be on the ground and in the air with advanced technology to get a better read on soil moisture. The Soil Moisture Experiment 2004 scientists also want to know what atmospheric conditions create long-lasting rainfalls over a large area. By determining which factors create large or small rainfall, hydrologists can provide better forecasts and know how much water will be available to people.
"The Western U.S. relies on water from the Southwestern monsoon system to fill its aquifers. Accurate measurements of soil moisture will assist in better water supply forecasts associated with the monsoon in the water-scarce western U.S," said Tom Jackson, USDA Agricultural Research Service hydrologist and lead for the Soil Moisture Experiment 2004.
From space, NASA's Aqua, Terra and QuikScat satellites will provide various measurements. Aqua's Advanced Microwave Scanning Radiometer instrument will measure soil moisture; Terra's Moderate Resolution Spectroradiometer will provide vegetation status; and Terra's Advanced Spaceborne Thermal Emission and Reflection Radiometer will measure the surface temperature. The SeaWinds instrument on the QuikScat satellite will observe the monsoon winds that bring in the moisture from the Pacific Ocean to the U.S. Southwest.
Closer to Earth, microwave radiometers on the Naval Research Laboratory P-3 aircraft and the Airborne Visible/Infrared Imaging Spectrometer on NASA's ER-2 high-altitude aircraft will fly over the areas to measure soil moisture. The Airborne Visible/Infrared Imaging Spectrometer will also help test new methods for remotely sensing water content in plants. Meanwhile, ground instruments will measure the temperature and percentage of moisture in soils from 2 to 40 inches deep. The satellite, airplane and ground data will be compared.
The Soil Moisture Experiment 2004 mission adds to two prior soil moisture experiments in 2002 and 2003, and is part of the larger North American Monsoon Experiment, led by NOAA, which is dedicated to understanding how the Southwestern U.S. monsoon season works. Monsoons need to be accurately understood and predicted by weather and climate models, because their influence on seasonal weather, including floods and droughts, can significantly disrupt regional economies and populations.
Dr. Eni Njoku of JPL is a member of the Aqua Advanced Microwave Scanning Radiometer science team. JPL manages Quikscat, Advanced Spaceborne Thermal Emission and Reflection Radiometer on Terra, and Airborne Visible/Infrared Imaging Spectrometer.
NASA's Earth Science Enterprise is dedicated to understanding the Earth as an integrated system and applying Earth system science to improve prediction of climate, weather and natural hazards using the unique vantage point of space.
For more information and images, on the Internet, visit: http://jpl.convio.net/site/R?i=-56VI_CZAENO-3BCLCXxIg.. . For more information about the SMEX Experiment on the Internet, visit: http://jpl.convio.net/site/R?i=NZG8RLnTP-9O-3BCLCXxIg.. .

2004: An Excellent Year for the Perseids part 2:Storm Watch for 2004

A bright Perseid streaks just below the Andromeda Galaxy, M31, during the 2002 shower. Joe Orman took this 5-minute exposure through a 40-millimeter lens at f/2.8 on Ektachrome P1600 slide film

The source of the Perseid shower is comet 109P/Swift-Tuttle, which orbits the Sun in a long, roughly 130-year ellipse. The comet sheds bits of its material each time it returns near the Sun. This debris keeps traveling along near the comet's orbital path, creating a sparse "river of rubble" in space.
The comet swept past the Sun during the summer of 1862 and made a return appearance in December 1992. By no coincidence, in the early 1990s the Perseids performed spectacularly — displaying a new, additional, much briefer peak with outbursts of up to several hundred meteors per hour in 1991, 1992, and 1993. This new peak was slightly offset in time from the weaker, longer-lasting "traditional" peak of Perseid activity.
In the years after the comet's departure, the strong, new Perseid peak decreased. For the last three years it has failed to appear at all. Accordingly, Perseid forecasts have generally returned to normal — with the maximum lasting about 12 hours centered on the time when the Earth is at the place in its orbit marked by the Sun's ecliptic longitude being 140.0° (equinox 2000.0).
In 2004 that time is 11h Universal Time on August 12th (7 a.m. Eastern Daylight Time, 4 a.m. Pacific Daylight Time). So North America, especially the West and Hawaii, is optimally positioned to catch the peak.
The consensus among meteor astronomers is that the particles of the new, 1990s peak were probably shed by Comet Swift-Tuttle during its swing by the Sun in 1862, and that as far as this rich filament of meteoroids is concerned, the show is over. But now, astronomers Esko Lyytinen of Finland and Tom Van Flandern of Washington, DC, suggest that the new Perseid peak could stage a return appearance in 2004. They predict that this year, the one-revolution rubble trail released in 1862 will be passing just 0.00132 astronomical unit (about 200,000 km) inside Earth's orbit at the time of solar longitude 139.440°. That's 20:50 UT on August 11th, favoring meteor watchers in Eastern Europe and eastern North Africa eastward to central Russia, India, and western China.
Lyytinen and Van Flandern base their prediction on the same techniques they used (rather successfully) in forecasting the intensities of the Leonid showers from 1999 through 2002. "It is very uncertain what kind of a shower this will give," notes Lyytinen. "If the numbers of particles released for the 1862 trail were the same as for the Leonid parent comet, I would say a ZHR [zenith hourly rate] of around 100 is possible. But," he adds, "we must also consider that the Perseid parent comet is a lot bigger than the Leonid comet, so there may even be a slight chance of storm-level activity," meaning a ZHR of 1,000 or more. Lyytinen and Van Flandern believe that most of these meteors could be rather faint, 3rd and 4th magnitude. If an outburst happens, it is likely to last no more than about 40 minutes.
Last, because recent perturbations by Jupiter are directing old Perseid meteoroids about 0.01 a.u. closer to the Sun, the core of the broader, "traditional" stream may be shifted closer to Earth،s orbit, resulting in a stronger-than-average annual shower. In fact, Lyytinen and Van Flandern suspect that the Perseids tend to put on stronger-than-average displays at 12-year intervals (12 years being Jupiter's orbital period), and that 2004 is one of the favored years. The 1992 display might not qualify for comparison because the parent comet was nearby — but 1980 brought an excellent show punctuated by many fireballs, and 1968 was rated quite good despite bright moonlight.
Will we be similarly rewarded this year? If so, the enhancement would come into play only around the date of the normal maximum, perhaps even appearing as a new, additional peak.
So there could hardly be more incentive for meteor watchers to be out in force this month. One thing is certain: the Moon will be dark and the meteors bright.

2004: An Excellent Year for the Perseids :

A bright Perseid flashed across the horns of Taurus before dawn on August 13, 2002, while Vincent Varnas was photographing from Stevenson, Washington. He used a 35-mm f/2 lens and Fujicolor Press 1600 film for this lucky 20-second exposure, one of many he took during 2½ hours of sky shooting. To the meteor’s lower left is Mars; to its right are Aldebaran and the Hyades, with the Pleiades above.

Circumstances will be nearly ideal for watching the annual Perseid meteor shower at its predicted maximum late on the night of August 11–12. Many families on August vacations at dark, country sites discover these meteors on their own, and late-summer campers often pull their sleeping bags out of their tents to enjoy this Old Faithful shower.
The Perseids are one of the two strongest and most dependable annual meteor showers (the Geminids of December are the other). Earth’s orbit carries us through the densest part of the Perseid meteoroid stream every year around August 11th or 12th, so these “shooting stars” appear almost like clockwork. Their rates, however, can vary a lot from year to year. An observer under a dark sky might typically see more than 60 Perseids per hour between midnight and dawn. Since the waning crescent Moon will be only three days from new at the time of shower maximum, this is an opportune year for watching them.
But that is only one reason why anticipation is running high among meteor observers. How the 2004 shower will actually perform is anybody’s guess — but it will probably be better than normal, and there’s a chance it could be spectacular.
Meteor Basics
The meteoroids of the Perseid stream range in size from pebbles to sand grains and have a consistency like bits of ash. They ram into our upper atmosphere at a speed of 60 kilometers per second, creating incandescent trails of shocked, ionized air as they vaporize.
On the peak night, the Perseids will appear to diverge from a patch of sky between Perseus and Cassiopeia just east of the famous Double Cluster. The meteors’ apparent divergence from this radiant point is an effect of perspective; the meteoroids are actually traveling in parallel through space. Meteors appearing near the radiant will display short trails because we see them nearly end on, while those far from the radiant, seen broadside, look much longer.
In the early-evening hours the radiant is low in the north-northeast, so the meteors strike the upper atmosphere at a low angle — and therefore we see comparatively few of them per square kilometer at the atmosphere’s top. As the night advances, the radiant rises higher in the northeast, the meteors arrive more nearly straight down, and so we see more of them. By the time morning twilight begins, the radiant has climbed to around 60° altitude for observers at midnorthern latitudes.
If it’s cloudy on the peak night, don’t despair; for one or two nights before and after, rates are still roughly a quarter to half of the maximum. In fact, the first few forerunners of the shower may show up as early as July 20th; the last stragglers have been recorded as late as August 24th.
Interference by moonlight this year will be minor, especially after the peak date, permitting night-after-night monitoring of the shower’s buildup and decline. On the morning of August 10th the thick waning crescent Moon won’t rise until about 1 a.m. local daylight time for observers in midnorthern latitudes. On the 12th, a thinner crescent will come up about 2:30 a.m. The Moon is new on the 15th, and for a week afterward the waxing crescent will set before midnight.
Meteor watching is simple. Pick an observing site that’s free of glary lights nearby, has an open view of the sky, and preferably is as far as possible out from under city light pollution. Don’t forget the mosquito repellent. Bundle up in blankets or a sleeping bag, lie back, and gaze into the stars. The direction to watch is wherever your sky is darkest, usually straight up. For more observing hints, see