Researchers: ET should write, not call

By Robert Roy Britt
SPACE.com
Thursday, September 2, 2004 Posted: 4:04 PM EDT (2004 GMT)

	The Voyager spacecraft carry records with 115 images and a variety of natural sounds from Earth, along with music from different cultures and eras.
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(SPACE.com) -- A fresh perspective on searching for aliens suggests ET is more likely to send us something akin to a message in a bottle rather than relying on energy-intensive, inefficient radio messages.

The professional hunt for ET depend largely on huge telescopes that scan for electronic intelligence in the ether, on the assumption that an brainy, technologically advanced civilization might try to reach out to others, or that their communications would leak into space.

But sending a signal across the cosmos is expensive an inefficient, argues Christopher Rose, a professor of electrical and computer engineering at Rutgers University. The idea is detailed in the August 25 issue of the journal Nature.

Tortoise and hare

Rose and physicist Gregory Wright initially set out to learn how to send the most information over a wireless channel. They then considered the amount of energy needed to send a signal over greater distances. As logic suggests, more energy is needed to send a message farther, and the signal weakens.

Radio waves, laser beams or X-ray pulses and other electromagnetic signals all travel at the speed of light. But the farther they go, the more they disperse. That makes them harder to detect.

"Think of a flashlight beam," Rose said. "Its intensity decreases as it gets farther from its source."

Seth Shostak knows about this problem. Shostak worked on the SETI Institute's Project Phoenix, a just-finished search for extraterrestrial radio signals (they didn't hear any) that was the most comprehensive so far. Not involved in Rose's research, Shostak wrote recently that sending a barely detectable radio-based signal across 100 light-years and in all directions would require 100 billion watts of power. Translation: You'd have to focus the output of all American power planets to do the job.

Interstellar radio programs face another problem in garnering listeners. Once an electronic signal passes its intended recipient, it is gone for good. If the creatures on a target planet have their electronic ears tuned to some other frequency when a signal arrives, or if they have yet to develop the right listening technology, the effort to make contact is wasted.

A written message in a space capsule, however, could have landed on Earth millennia ago and await discovery. And a spacecraft, once up to speed, can cruise for long periods with little additional power input.

Time to spare?

The downside to the message-in-a-bottle approach: Human technology, at least, can't propel a spacecraft to even a significant fraction of light-speed. So getting a note from one star system to the next would take more generations than the average human mind can contemplate.

The most distant probe sent by earthlings is Voyager 1, just crossing the outer boundary of the solar system. After a 27-year journey it is 90 times the distance from Earth to the Sun, or nearly 8.4 billion miles (13.5 billion kilometers). A radio signal can go that far and back in about a day.

The next nearest stars, in the Alpha Centauri system, are 4.3 light-years distant. That's more than 3,000 times what Voyager has so far covered.

However, so long as time is not of the essence, Rose and Wright figure hard copy would be the preferred method to talk across the stars.

"If haste is unimportant, sending messages inscribed on some material can be strikingly more efficient than communicating by electromagnetic waves," Rose said.

Outbound examples

Further, he points out, long messages are handled more efficiently by inscription.

NASA's two Voyager probes exhibit such an effort. Each carries a 12-inch, gold-plated copper disk with sounds and images that portray terrestrial life and culture. The cost to send the records was practically inconsequential to the overall price tag of the mission, whose main purpose was to study the planets.

Radio pulses announcing anything more than "we exist" would consume more energy (which requires money) for every word.

Rose is not against listening. He just thinks looking might prove more fruitful. He also notes that messages might not arrive as language, per se. Perhaps organic material embedded in an asteroid, the Moon or a satellite of Jupiter would reveal the presence of life elsewhere. That of course is not a new idea. Other scientists have considered that unintelligent (microbial) life could even travel between planets embedded in a rock kicked up by an asteroid impact. No calling card required.

Reports of SETI@home Extraterrestrial Signal Highly Exaggerated by Amir Alexander September 2, 2004: A rash of reports in recent days that SETI@home has discovered a likely signal from an alien civilization are highly exaggerated, says SETI@home Chief Scientist Dan Werthimer of U.C. Berkeley. The storm was initiated by an article in New Scientist magazine, which reported about SETI@home’s most promising candidate signal to date, and speculated about its possible origins. Like all of SETI@home’s 5 billion potential signals, this candidate, labeled SHGb02+14a, was assigned a numerical score representing the statistical likelihood that it is indeed an intelligent extraterrestrial signal. Its relatively high score placed it among the 200 “top candidates” selected for the targeted reobservation sessions that took place in March of 2003 at the Arecibo Radio Observaotry. Of all the candidates targeted in the sessions, however, SHGb02+14a was one of the very few to be confirmed during the reobservations, and the only one whose score following the sessions actually went up. A sky map of the reobservations that took place at Arecibo in March of 2003. The blue areas represent the plane of the Milky Way, the gray strip the band of sky seen from Arecibo. The squares mark the locations of the signal candidates revisited during the reobservation sessions. Image: University of California/SETI@home While this makes SHGb02+14a interesting, the chances that it actually represents an intelligent signal from beyond remain extremely slim. Random chance alone would make it probable that at least one of the billions of candidates detected by SETI@home would be observed on three separate occasions, as was the case for this candidate. Furthermore, as we reported in the SETI@home Update of May 17, 2004, the fact that this candidate’s frequency drifts rapidly makes it extremely improbable that it is a transmission from extraterrestrials. Because of the drift, explained Werthimer, “if we had looked at the sky even a few seconds later we wouldn’t have found a match” for this candidate. A signal that drifts so quickly that it can only be heard for seconds at a time at a given frequency can only be detected by blind luck. Needless to say, such a transmission is an unlikely vehicle for message from an advanced civilization. In addition, SETI@home Project Director David Anderson of U.C. Berkeley pointed out that SHGb02+14a is a candidate of a type known as a "barycentrically corrected gaussian." A true transmission of this type, he explained, would remain in a more or less fixed narrow-band frequency, and not drift rapidly as this signal does. At Arecibo the giant radio telescope still scans the sky, looking for an alien transmission. Around the world, millions are still crunching SETI@home data on their personal computers. The Search for extraterrestrial intelligence continues at full speed, but as of now there is no breakthrough. Of course, this could change at any time… We promise to keep you posted.

Fonte: http://planetary.org/news/2004/seti_signal_0902.html

Abraços

Hurricane Frances battered the Kennedy Space Center with sustained winds of more than 70 mph, ripping off an estimated 40,000 square feet of siding on the cavernous Vehicle Assembly Building and partially destroying the roof of a critical heat shield tile facility needed for NASA's shuttle return to flight effort.

Recovering from the impact of Frances could delay NASA's first post-Columbia shuttle flight, now targeted for March, officials said today. But center Director Jim Kennedy said the damage, while the worst in spaceport history, was not a disaster "by any stretch of the imagination" and that it was too soon to say what impact it might have on the agency's return-to-flight efforts.

"It's way too early for us to state that we do or don't have a problem," he said. "But as you know, we were working hard to protect the shuttle return-to-flight date of March and we'll just have to see how that goes."

More important than the shuttle's eventual launch date is the potential impact of Hurricane Ivan, a powerful storm that some computer models show tracking toward Florida's east coast. Given the damage caused by the category 1 winds of Hurricane Frances, Kennedy sees Ivan as a potential "doomsday scenario" that could affect the future of America's manned space program.

"I don't want to speculate on what possible worse damage we could have with a category 2, 3, 4, 5 direct hit," Kennedy said. "It would certainly be significant to the future of human spaceflight."

NASA closed the space center last Thursday, sending 12,000 contractors and 2,000 civil servants home to make their own preparations for Frances. The agency's three space shuttles, mounted on jacks in their Orbiter Processing Facility hangars, were powered down, their cargo bay doors closed and their landing gear raised and stowed.

Sandbags and plywood panels were used to shore up vulnerable doors and windows while NASA trucks and cranes were moved inside the protection of the Vehicle Assembly Building.

A disaster assessment-response team, or DART, began surveying damage today and a teleconference with senior NASA managers is planned tomorrow to review the results.

A preliminary inspection shows NASA's three multi-billion-dollar space shuttles - Discovery, Atlantis and Endeavour - came through the hurricane unscathed, as did critical hardware bound for the international space station as well as an astronomy satellite scheduled for launch next month.

But the Vehicle Assembly Building, or VAB, suffered major damage to its protective skin and a facility that manufactures and repairs heat-shield tiles for the shuttle fleet lost at least part of its roof.

"The tile facility, which is located out in the general area of the OPFs and the VAB, has taken significant loss," Kennedy said. "We believe the roof is partially gone, it has extensive water damage within the facility. That could possibly be a very difficult situation to deal with because tile manufacturing is to some extent on the critical path for return to flight."

The Vehicle Assembly Building is a national icon, a massive, 525-foot-tall cube originally built to assemble 36-story Saturn 5 moon rockets. Today, NASA uses the facility to build up space shuttle boosters atop mobile launch platforms, to attach the shuttle's solid-fuel external tank and the orbiter itself prior to rollout to the launch pad.

The only flight hardware in the VAB when Frances struck were two external tanks, both protected by dense scaffolding and access platforms, and two booster "aft skirts" that are the first pieces mounted to the launch platform.

Engineers estimate the VAB lost about 1,000 4-by-10 foot aluminum panels on its south and east sides, starting about 100 feet up and extending to a height of 350 feet or so. "And that would include typically not only the outer panel, but the insulation and in some cases, a sub panel behind it to where it's like an open window to the VAB," Kennedy said.

Repairing the VAB is "certainly a high priority for us," he said. "As you think about things that are time critical, the VAB repair is one. Not only because we need the VAB to process hardware, but I am concerned about Ivan and 40,000 square feet of open window exposed to Ivan.

"I will tell you the preliminary input of the facilities folks was they really didn't know how, with five days notice before Ivan arrives, how we could do much in temporary repair. ... They have great concern about how they might be able to do that with just a few days' time."

Hurricane Charley, which skirted the northern boundary of the Kennedy Space Center last month, caused some $700,000 damage. The cost to recover from Frances, which was barely a category 1 storm when it hit Brevard County, is not yet known.

"I don't consider this to be a disaster by any stretch of the imagination," Kennedy said. "How big the bump in the road (for return to flight) is to be determined. It's a bump in the road for sure. You may or may now know that with Hurricane Charley, which just kissed the northern tip of Kennedy Space Center with the south eyewall as it passed across Volusia County, we took a $700,000 damage. This one is going to be significantly more than that. But how significant, I don't know so how big the bump in the road is, we don't know."

All in all, he said, "the initial feeling was that we had dodged a big bullet."

"If you think about what we believed we might have to deal with five, six, seven days ago, was a hurricane category 4, with the possibility of growth to a five and a direct hit to the Kennedy Space Center," he said. "I was significantly worried about the future of human space flight based upon that doomsday scenario.

"So when they drove on site today and saw most of the buildings intact, very few trees down, most of the power lines still up ... it wasn't the appearance of a war zone like we have seen on (in hurricane newscasts). It wasn't like that. So I feel very fortunate it's as minimal as it is."

As for Hurricane Ivan, Kennedy said his team of forecasters, led by John Madura, believe the storm has the potential to pose the same sort of doomsday scenario he worried about last week.

"Some of the models show it coming up close to the space coast of Florida," Kennedy said. "John Madura's one of the best and when he's worried, I'm worried."

Hurricane Frances battered the Kennedy Space Center with sustained winds of more than 70 mph, ripping off an estimated 40,000 square feet of siding on the cavernous Vehicle Assembly Building and partially destroying the roof of a critical heat shield tile facility needed for NASA's shuttle return to flight effort.

Recovering from the impact of Frances could delay NASA's first post-Columbia shuttle flight, now targeted for March, officials said today. But center Director Jim Kennedy said the damage, while the worst in spaceport history, was not a disaster "by any stretch of the imagination" and that it was too soon to say what impact it might have on the agency's return-to-flight efforts.

"It's way too early for us to state that we do or don't have a problem," he said. "But as you know, we were working hard to protect the shuttle return-to-flight date of March and we'll just have to see how that goes."

More important than the shuttle's eventual launch date is the potential impact of Hurricane Ivan, a powerful storm that some computer models show tracking toward Florida's east coast. Given the damage caused by the category 1 winds of Hurricane Frances, Kennedy sees Ivan as a potential "doomsday scenario" that could affect the future of America's manned space program.

"I don't want to speculate on what possible worse damage we could have with a category 2, 3, 4, 5 direct hit," Kennedy said. "It would certainly be significant to the future of human spaceflight."

NASA closed the space center last Thursday, sending 12,000 contractors and 2,000 civil servants home to make their own preparations for Frances. The agency's three space shuttles, mounted on jacks in their Orbiter Processing Facility hangars, were powered down, their cargo bay doors closed and their landing gear raised and stowed.

Sandbags and plywood panels were used to shore up vulnerable doors and windows while NASA trucks and cranes were moved inside the protection of the Vehicle Assembly Building.

A disaster assessment-response team, or DART, began surveying damage today and a teleconference with senior NASA managers is planned tomorrow to review the results.

A preliminary inspection shows NASA's three multi-billion-dollar space shuttles - Discovery, Atlantis and Endeavour - came through the hurricane unscathed, as did critical hardware bound for the international space station as well as an astronomy satellite scheduled for launch next month.

But the Vehicle Assembly Building, or VAB, suffered major damage to its protective skin and a facility that manufactures and repairs heat-shield tiles for the shuttle fleet lost at least part of its roof.

"The tile facility, which is located out in the general area of the OPFs and the VAB, has taken significant loss," Kennedy said. "We believe the roof is partially gone, it has extensive water damage within the facility. That could possibly be a very difficult situation to deal with because tile manufacturing is to some extent on the critical path for return to flight."

The Vehicle Assembly Building is a national icon, a massive, 525-foot-tall cube originally built to assemble 36-story Saturn 5 moon rockets. Today, NASA uses the facility to build up space shuttle boosters atop mobile launch platforms, to attach the shuttle's solid-fuel external tank and the orbiter itself prior to rollout to the launch pad.

The only flight hardware in the VAB when Frances struck were two external tanks, both protected by dense scaffolding and access platforms, and two booster "aft skirts" that are the first pieces mounted to the launch platform.

Engineers estimate the VAB lost about 1,000 4-by-10 foot aluminum panels on its south and east sides, starting about 100 feet up and extending to a height of 350 feet or so. "And that would include typically not only the outer panel, but the insulation and in some cases, a sub panel behind it to where it's like an open window to the VAB," Kennedy said.

Repairing the VAB is "certainly a high priority for us," he said. "As you think about things that are time critical, the VAB repair is one. Not only because we need the VAB to process hardware, but I am concerned about Ivan and 40,000 square feet of open window exposed to Ivan.

"I will tell you the preliminary input of the facilities folks was they really didn't know how, with five days notice before Ivan arrives, how we could do much in temporary repair. ... They have great concern about how they might be able to do that with just a few days' time."

Hurricane Charley, which skirted the northern boundary of the Kennedy Space Center last month, caused some $700,000 damage. The cost to recover from Frances, which was barely a category 1 storm when it hit Brevard County, is not yet known.

"I don't consider this to be a disaster by any stretch of the imagination," Kennedy said. "How big the bump in the road (for return to flight) is to be determined. It's a bump in the road for sure. You may or may now know that with Hurricane Charley, which just kissed the northern tip of Kennedy Space Center with the south eyewall as it passed across Volusia County, we took a $700,000 damage. This one is going to be significantly more than that. But how significant, I don't know so how big the bump in the road is, we don't know."

All in all, he said, "the initial feeling was that we had dodged a big bullet."

"If you think about what we believed we might have to deal with five, six, seven days ago, was a hurricane category 4, with the possibility of growth to a five and a direct hit to the Kennedy Space Center," he said. "I was significantly worried about the future of human space flight based upon that doomsday scenario.

"So when they drove on site today and saw most of the buildings intact, very few trees down, most of the power lines still up ... it wasn't the appearance of a war zone like we have seen on (in hurricane newscasts). It wasn't like that. So I feel very fortunate it's as minimal as it is."

As for Hurricane Ivan, Kennedy said his team of forecasters, led by John Madura, believe the storm has the potential to pose the same sort of doomsday scenario he worried about last week.

"Some of the models show it coming up close to the space coast of Florida," Kennedy said. "John Madura's one of the best and when he's worried, I'm worried."

Genesis set for stellar return from space

By Michael Coren
CNN
Tuesday, September 7, 2004 Posted: 2043 GMT (0443 HKT)

	An artist's image of the midair retrieval of the Genesis sample return capsule. Image:
	RELATED • Animation: Genesis retrieval • NASA: Genesis mission • NASA: Genesis interactive YOUR E-MAIL ALERTS National Aeronautics and Space Administration (NASA) Space Exploration Science and Technology Jet Propulsion Laboratory or Create your own Manage alerts | What is this? Genesis facts Days of spaceflight 1125 Days of Solar Wind Collection 884 Sample material collected approx. 0.4 milligrams Timeline Launch August 8, 2001 Halo Orbit Insertion November 16, 2001 Start of Sample Collection December 3, 2001 Complete Sample Collection April 2, 2004 Earth "Flyby" on way to L2 May 2, 2004 Capsule Return to Earth September 8, 2004 Samples to JSC September 11, 2004

(CNN) -- A daring trip to study the solar wind will end on Wednesday with the midair retrieval of extraterrestrial samples above the Utah desert. However, the scientific journey is only beginning.

"We are bringing a piece of the sun down to Earth," said Charles Elachi, the director of the Jet Propulsion Laboratory in Pasadena, California. "That's going to give us some fundamental understanding of our origins."

Scientists say the data will not only reveal the composition of the sun, but illuminate how our planet could have formed from clouds of stellar dust.

"Four and a half billion years ago, all of the matter of the solar system, including us, was part of a giant molecular cloud," said Don Burnett, principal investigator for the Genesis mission. "Genesis is providing the chemical composition of that solar nebula. ...The material is still stored for us in the surface of the sun."

Two helicopters will be poised above a Utah Air Force base to snag the Genesis spacecraft's return capsule. The sturdy container contains atomic isotopes collected as particles streaming off the sun, known as the solar wind.

The unorthodox midair retrieval will snag the first extraterrestrial samples since the Apollo missions in the 1970s.

Genesis collected the particles over the last two years on special tiles made from silicon, diamond, gold, sapphire and other materials. The solar particles, embedded in the collector tiles, were ejected at about 280 miles per second (450 km/s) from the sun's scorching corona or outer atmosphere.

Genesis will fill in an astronomical blank spot about its makeup.

"What we've been missing is a starting point," says Burnett. "These samples allow precise measurements of the abundance of elements and isotopes in the sun."

Our star accounts for 99 percent of the mass in the solar system. It is composed mostly of isotopes of hydrogen and helium and includes 60 other elements including neon, argon carbon, nitrogen, oxygen and iron.

In all, Genesis has collected the equivalent of a few grains of the material. Scientists say that is enough to keep researchers busy for decades.

"We'll have a reservoir of solar matter," said Burnett. "We can meet the requirements for (studying ) the solar composition through the 21st century."

Genesis mission

Launched in 2001 from Cape Canaveral, the Genesis spacecraft traveled beyond the protective cloak of Earth's magnetosphere for two years before heading home. Because of Earth's electromagnetic field, much of the sun's deadly radiation and material never reaches the planet's surface.

In April, the craft ejected a 500-pound return capsule for return to Earth.

It has been approaching the planet at a leisurely 600 mph. By the time it reaches Earth's atmosphere, the craft will be racing toward the planet at more than 25,000 mph. It will use a series of parachutes to slow its descent.

On Wednesday, it is expected to enter the atmosphere at 11:55 am ET above Oregon and, just two minutes later, glide down over the Utah desert. The main parachute, a wing-like parafoil, will deploy during its decent and a helicopter will snatch the Genesis capsule when it is still about a mile off the ground.

This daring retrieval method will protect the samples and sensitive instruments during reentry. A crash landing, even at the capsule's relatively slow speed of 9 mph, could ruin some of the data collected during the mission.

The prospects for success look good according to NASA's retrieval partner in the mission, the aerospace firm Vertigo.

"If they can find it, the success rate is very high," said Vertigo official Roy Haggard.

A modified helicopter -- with a winch, hydraulic capture pole and hundreds of feet of line -- will follow the capsule by radar until it moves in and snags the parafoil. Because the Genesis capsule must repressurize in the upper atmosphere, scientists want to minimize the sample's exposure to air and possible contamination.

Once it is secured at a NASA facility, scientists can breathe easier, said Burnett.

"After that we can take our time, and we will see what we have," he said.

Frances tears panels from NASA shuttle hangar

Monday, September 6, 2004 Posted: 1917 GMT (0317 HKT)

	The Vehicle Assembly Building at Kennedy Space Center before sustaining hurricane damage.
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(CNN) -- NASA managers worried Monday about the prospect of Hurricane Ivan after Hurricane Frances ripped about 1,000 4-by-10-foot aluminum panels off one side of its massive Vehicle Assembly Building, Kennedy Space Center director Jim Kennedy said.

Kennedy said center staff will concentrate on protecting the 40-story, 560-foot building from further damage.

"I don't see how we could do too much to repair those openings in a few days' time," he said.

Kennedy said the checkerboard-patterned damage was the worst storm damage in the center's history -- like 40,000 square feet of new windows opened from the 100-foot level to the 350-foot level.

Roof damage, he said, was unknown.

Hurricane Charley caused $700,000 in damage three weeks ago, but "this one is going to be significantly more than that," Kennedy said.

The center registered top sustained winds above 70 mph and gusts up to 94 mph. But nearby Cape Canaveral registered gusts as high as 124 mph.

The VAB, built in 1965 to assemble the Apollo moon program's gigantic Saturn V rockets, is now used to attach the shuttle's boosters. Kennedy said two external tanks were inside the building during the storm.

"They are somewhat enclosed, and we think they are protected from the elements," he said.

The space center had also moved cars and trucks into the building to ride out the storm.

Other center facilities fared better. Two of the three Orbiter Processing Facilities had full power Monday afternoon with only a little mopping up of water needed, Kennedy said. OPF 3 -- the orbiter Discovery's hangar -- has no power, he said.

The Space Station Processing Facility also came through the storm with few problems, and has full power.

The shuttle program's tile manufacturing facility, however, suffered "extensive water damage" throughout and could be a "huge problem," Kennedy said. NASA managers are looking for options, and could move the work to a facility in Palmdale, Calif.

Inspectors have not yet had a look at launch pads, he said.

Kennedy said it is too early to figure how the damage might affect the shuttle program's plans to return to flight for the first time since Columbia's fatal accident on February 1, 2003, but more would be known after a 500-person team currently on site finishes its work.

"I don't consider this to be a disaster by any stretch of the imagination," he said. "How big the bump in the road it is, is to be determined. It's a bump in the road for sure."

Current plans call for a shuttle launch in March or April 2005.

The VAB was the tallest building in Florida until 1974.

Fri Sep 3, 7:49 AM ET

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By FRANK GRIFFITHS, Associated Press Writer

SAN JUAN, Puerto Rico - The radio telescope at Puerto Rico's Arecibo Observatory will begin mapping the known galaxy on Friday, scientists said.

Palm Power We rank the best PDAs, share some synching tips, and show how PDAs will only get better.

The dark material that coats one hemisphere of Saturn's moon Iapetus is very dark, as these two processed views of the same image demonstrate.

Credit: NASA/JPL/University of Arizona Download larger image version here

The image was taken in visible light, with the Cassini spacecraft narrow angle camera from a distance of 2.9 million kilometers (1.8 million miles) from Iapetus, and at a Sun-Iapetus-spacecraft, or phase angle of 89 degrees. The image scale is 17 kilometers (11 miles) per pixel. The image has been magnified by a factor of four to aid visibility.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras, were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

NASA's Spitzer Space Telescope has set its infrared sight on a major galactic collision and witnessed not death, but a teeming nest of life.

The colliding galaxies, called the Antennae galaxies, are in the process of merging together. As they churn into each other, they throw off massive streamers of stars and dark clouds of dust. Spitzer's heat-seeking eyes peered through that dust and found a hidden population of newborn stars.

The new Spitzer image, available at http://www.spitzer.caltech.edu/Media/releases/ssc2004-14/visuals.shtml, is reported in one of 86 Spitzer papers published in the September issue of The Astrophysical Journal Supplement. This special all-Spitzer issue comes just after the one-year anniversary of the observatory's launch, and testifies to its tremendously successful first year in space.

"This abundance of Spitzer papers just one year after launch shows that the telescope is truly providing a new window on the universe," said Dr. Michael Werner, project scientist for Spitzer at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "These papers report the earliest results, so the best is yet to come."

In the latest Antennae galaxies study, Spitzer uncovered a new generation of stars at the site where the two galaxies clash.

"We theorized that there were stars forming at that site, but we weren't sure to what degree," said Dr. Zhong Wang, lead author of the new paper and an astronomer at the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass. "Now we see that the majority of star-forming activity in both galaxies occurs in the overlap regions where the two meet."

The Antennae galaxies are a classic example of a galactic merger in action. These two spiral galaxies, located 68 million light-years away from Earth, began falling into each other around a common center of gravity about 800 million years ago. As they continue to crash together, clouds of gas are shocked and compressed in a process thought to trigger the birth of new stars. Astronomers believe that the two galaxies will ultimately merge into one spheroidal-shaped galaxy, leaving only hints of their varied pasts.

Galactic mergers are common throughout the universe and play a key role in determining how galaxies grow and evolve. Our own Milky Way galaxy, for example, will eventually collide with our closest neighbor, the Andromeda galaxy.

Previous images of the Antennae taken by visible-light telescopes show striking views of the swirling duo, with bright pockets of young stars dotting the spiral arms. At the center of the galaxies, however, where the two overlap, only a dark cloud of dust can be seen. In the new false-color Spitzer image, which has been combined with an image from a ground-based, visible-light telescope to highlight new features, this cloud of buried stars appears bright red. The visible-light information, on the other hand, is colored blue and indicates regions containing older stars. The nuclei, or centers, of the two galaxies are white.

"This more complete picture of star-formation in the Antennae will help us better understand the evolution of colliding galaxies, and the eventual fate of our own," said Dr. Giovanni Fazio, a co-author of the research and an astronomer at the Harvard-Smithsonian Center for Astrophysics." Fazio is principal investigator for the infrared array camera on Spitzer, which captured the new Antennae image.

JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. JPL is a division of Caltech. Spitzer's infrared array camera was built by NASA Goddard Space Flight Center, Greenbelt, Md.

Information about Spitzer can be found at http://www.spitzer.caltech.edu.

Whitney Clavin (818) 354-4673 Jet Propulsion Laboratory, Pasadena, Calif.

2004-218

The Cassini spacecraft has taken the most detailed temperature measurements to date of Saturn's rings. Data taken by the composite infrared spectrometer instrument on the spacecraft while entering Saturn's orbit show the cool and relatively warm regions of the rings.

Credit: NASA/JPL/University of Arizona

The data show that the opaque region of the rings, like the outer A ring (on the far right) and the middle B ring, are cooler, while more transparent sections, like the Cassini Division (in red just inside the A ring) or the inner C ring (shown in yellow and red), are warmer. Scientists had predicted this might be the case, because the opaque ring areas would let less light through, and the transparent areas, more. These results also show, for the first time, that individual ringlets in the C ring and the Cassini Division are cooler than the surrounding, more transparent regions.

The temperature data were taken on July 1, 2004, shortly after Saturn orbit insertion. Cassini is so close to the planet that no pictures of the unlit side of the rings are available, hence the temperature data was mapped onto a picture of the lit side of the rings. Saturn is overexposed and pure white in this picture. Saturn's moon Enceladus is visible below the rings, toward the center.

The composite infrared spectrometer, one of 12 instruments on Cassini, will measure infrared emissions from atmospheres, rings and surfaces. This spectrometer will create vertical profiles of temperature and gas composition for the atmospheres of Titan and Saturn. During Cassini's four-year tour, the instrument will also gather information on the thermal properties and composition of Saturn's rings and icy moons. 

Cassini-Huygens is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science and Mission Directorate, Washington. The Cassini orbiter was designed, developed and assembled at JPL. The Composite Infrared Spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md.

The dark material that coats one hemisphere of Saturn's moon Iapetus is very dark, as these two processed views of the same image demonstrate.

Credit: NASA/JPL/University of Arizona Download larger image version here

The image was taken in visible light, with the Cassini spacecraft narrow angle camera from a distance of 2.9 million kilometers (1.8 million miles) from Iapetus, and at a Sun-Iapetus-spacecraft, or phase angle of 89 degrees. The image scale is 17 kilometers (11 miles) per pixel. The image has been magnified by a factor of four to aid visibility.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space Science, Washington, D.C. The Cassini orbiter and its two onboard cameras, were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

Sonda Genesis trará à Terra partículas do Sol

 da BBC Brasil

A sonda espacial Genesis, que deixou a Terra em 2001 para capturar partículas emanadas pelo Sol, vai entregar o que coletou aos pesquisadores nesta quarta-feira.

Ela vai ejetar uma cápsula que entrará na atmosfera a uma velocidade de 40 mil km/h, antes de desacelerar, com a ajuda de um pára-quedas, e cair sobre o deserto de Utah, nos Estados Unidos.

Pilotos de helicópteros designados para a tarefa esperam conseguir enganchar o pára-quedas durante a queda, para impedir que a cápsula se choque contra o solo.

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