Old, pressed flowers give climate clues

Ecologists compared samples of early spider orchids, held in collections with notes showing the exact day in spring when they were picked in southern England from 1848-1958, and dates when the same flower blossomed in the wild from 1975-2006.

"Warmer years were associated with earlier flowering ... In both cases flowering was advanced by about six days per 1 degree Celsius (1.8 Fahrenheit) rise in average spring temperature," they wrote in the Journal of Ecology after cross-checking with local temperature records.

The match between higher temperatures and quicker flowering for both old and modern orchids showed for the first time that botanical collections could be a reliable source to study climate, even if temperature records were lacking, they said.

Vast numbers of specimens of plants and animals are in collections around the world, some of them dating back 250 years and long before there were reliable temperature records in many nations.

"It potentially opens up new uses for ... specimens -- this could provide us with long-term data about climate," said Anthony Davy, a professor at the University of East Anglia who was a co-author of the study led by colleague Karen Robbirt.

The U.N. panel of climate scientists said in a 2007 report that average world temperatures rose 0.7 degree Celsius (1.3 F) over the 19th century, mainly in recent decades due to a build-up of greenhouse gases from burning fossil fuels.

Tree rings are among biological indicators of climate in past centuries, caused by natural swings. Manmade global warming is very likely to be the dominant cause of warming in the past half-century, according to the U.N panel.

The 77 pressed orchids, picked when in full bloom, had meticulous records of dates and sites. Early spider orchids have greenish petals and a purple-brown part which looks like the back of a spider.

Davy told Reuters that spring temperatures were the main factor determining flowering times for orchids -- rather than the length of daylight or the changing availability of nutrients.

He said one issue for future study was whether climate change might bring a mismatch between the appearance of flowers and insects vital for their pollination. Bees, for instance, might not be around when fruit trees are in bloom.

Source: www.reuters.com

Do Cell Phones Cause Cancer?

There are safety-warning labels on cigarettes and alcohol. Now some groups are advocating that similar cautions be printed on cell phones.

Recently, a bill in the Maine state senate proposed a label warning users, especially children and pregnant women, of the risks of brain cancer from electromagnetic radiation emanating from the device.

But the Maine legislature voted down the bill in March, stating that the scientific evidence does not indicate a public health risk.

Yet, the debate rages on. Can cell phones really cause cancer?

Supporters of the Maine legislation argued that uncertainty about the long-term effects of cell phone radiation warranted public safety notices. They also pointed to a handful of European studies that linked brain and auditory nerve tumors with using cell phones for more than 10 years and at younger ages.

“I think my short answer is that the evidence isn’t 100 percent, but there’s a strong indication that, yes, cell phone use does cause cancer (over a long period of time),” said David Carpenter, director of the Institute for Health and Environment at the University of Albany, and an advocate for the Maine bill on cell phone warnings.

Carpenter points to a 2007 meta-analysis that associated ipsilateral auditory nerve tumors (acoustic neuromas) with people who had used cell phones for at least 10 years, as well as a 2009 Swedish study that found a heightened risk for brain tumors among people who had used cell phones for at least 10 years, especially for those under 20 years old.

Not surprisingly, cell phone industry insiders disagree.

“The peer-reviewed scientific evidence has overwhelmingly indicated that wireless devices, within the (radiation) limits established by the FCC, do not pose a public health risk or cause any adverse health effects,” said John Walls, vice president of public affairs for CTIA -- The Wireless Association, an international trade group that represents the wireless telecomm industry.

For instance, 2001 Danish study and 2006 follow-up found no relationship between cancer risk and long-term cell phone use among more than 400,000 users.

In addition, a statistical review from the National Institutes of Cancer revealed no rise in cancer incidence rates from 1975 to 2005 in relation to the rise in cell phone usage.

Joshua Muscat, a public health science professor at Pennsylvania State University who has studied the cancer-causing potential of cell phone radiation, also questions the connection.

“There is no known mechanism by which radio frequency fields generated by cell phones can cause cancer,” Muscat said.

Cell phone radiation is non-ionizing, which means it isn’t high-frequency enough to strip electrons from atoms and molecules and directly damage cellular DNA, like X-rays can.

Nevertheless, when you press a cell phone against your ear while it’s in use, head and brain tissues can absorb that vibrating, low-frequency radiation and heat. Because of that radiation effect, the Federal Communications Commission (FCC) sets specific absorption rates (SARs) that dictate the maximum amount of radiation cell phones and mobile devices can give off.

“The power output from these phones is extremely low,” Muscat told Discovery News. However, David Carpenter counters that the SARs don’t take into account the potential long-term damage of close-range exposure to heat-inducing radiation, especially in children.

“Those (FCC) levels are set by engineers and physicists, and those aren’t the people who should be setting health-based standards,” he said.

Carpenter thinks that the results from a large, 13-country study called Interphone, which consists of a series of 16 case-controlled studies conducted between 2000 and 2005, could finally settle the debate. Each of the Interphone studies recruited at least 100 people who had developed brain cancer or certain types of tumors, along with a healthy control group.

But it’s been hampered by methodological shortcomings. In many cases, the group was asked to describe their cell phone habits, which critics contend led to recall bias. So far, it still hasn’t rendered a final verdict.

For now, the National Cancer Institute, American Cancer Society, U.S. Food and Drug Administration, among other leading health agencies and organizations, aren’t ringing the alarm bells. For one thing, scientists have yet to pinpoint how the low-frequency cell phone radiation could cause cancer.

“(Cell phone radiation’s) effect in the body appears to be insufficient to produce the genetic damage typically associated with developing cancer,” said Robert N. Hoover, director of epidemiology for the National Cancer Institute, in an official statement to Congress. “To date, no alternative mechanism about how this exposure might result in cancer has been vetted adequately.”

Until scientists can unmask that “mechanism,” Carpenter urges consumers to play it safe and text message or hold cell phones away from their ears to limit radiation exposure.

Even Muscat from Penn State leaves a space -- albeit a narrow one -- for caution.

“It is a legitimate concern in the sense that there may be some unknown, undiscovered mechanism that could be promoting the development of cancer,” Muscat said. “This seems unlikely, but if one looks at other scientific disciplines such as cosmology or particle physics, there are often paradigm shifts that occur with new discoveries."
Source: http://dsc.discovery.com

Study: Cell Phone Towers Don’t Raise Cancer Risk

A recent study by British researchers at Imperial College London’s School of Public Health has found that, despite widespread concern over the safety of cell phones, children born to mothers who lived near cell phone towers while pregnant do not have an elevated risk of cancer.

The team examined nearly 2,000 cases of childhood cancer in Britain between 1999 and 2001, and found that there was no correlation between how close their mother lived to cell phone towers and incidence of cancer.

Various cancers were examined, including cancers of the brain and central nervous system, leukemia, and non-Hodgkin’s lymphoma. The researchers concluded, “There is no association between risk of early childhood cancers and estimates of the mother’s exposure to mobile phone base stations during pregnancy.” The study was published in the British Medical Journal.

Despite the alarm and media scares, repeated studies have found no link between cell phone use and disease. In fact, as physicist S.T. Lakshmikumar noted in Skeptical Inquirer magazine, the power in a standard cell phone would not be enough to cause problems: “The small amount of power being transmitted by the phone is traveling several kilometers to the tower. Also, the cell phone has to transmit this very little power in all directions. The small power in the direction of the tower passes through several walls and other obstructions, even people, without impeding the communication”

Thus, cell phone signals are everywhere—and probably passing through you as you read this. If the signals were carcinogenic, nearly everyone would have cancer.

There’s no question that cell phones can be dangerous. Many scientific, reputable studies have proved that. In fact, cell phone use has been banned in many states for exactly this reason. But the chief threat of cell phones is the distraction they cause, not the electromagnetic fields they emit. According to one study, drivers who are busy texting on their cell phones are six times more likely to get in an accident than those who do not.
Source: http://news.discovery.com/

Sun Rises on Discovery at Launch pad

Space shuttle Discovery completed its last planned trip to the launch pad at 1:49 a.m. at NASA's Kennedy Space Center in Florida. Technicians are connecting numerous cables and checking systems at Launch Pad 39A before the rotating service structure is moved over Discovery later today. Discovery left the Vehicle Assembly Building at about 7:23 p.m. Monday night to begin the slow, 3.4-mile crawl to the pad.

Discovery, which first launched Aug. 30, 1984, on STS-41D, is being readied for the STS-133 mission to the International Space Station. Liftoff is targeted for Nov. 1 at 4:40 p.m. EDT. This is scheduled to be the last mission for the oldest of NASA's three active orbiters.

Astronaut Steve Lindsey commands a veteran crew for STS-133, including Pilot Eric Boe and mission specialists Alvin Drew, Tim Kopra, Michael Barratt and Nicole Stott. They will take the supply- and equipment-laden Permanent Multipurpose Module to the station, along with the humanoid helper called Robonaut 2.

Source: www.nasa.gov

Hellish Venus Atmosphere May Have Had Cooling Effect

It may seem downright bizarre, but a new model of Venus' super-hot atmosphere suggests its greenhouse gases may actually be cooling the planet's interior.

These gases initially cause Venus' temperature to rise, but at a certain threshold, they can trigger dynamic processes – which researchers call "mobilization" – in the planet's crust that cool the mantle and overall surface temperature, researchers found.

Venus surface temperature, on average, is a scorching 860 degrees Fahrenheit (460 degrees Celsius).

"For some decades we've known that the large amount of greenhouse gases in the atmosphere of Venus cause the extreme heat we observe presently," said study leader Lena Noack of the German Aerospace Center in Berlin.

Carbon dioxide and other greenhouses gases that led to Venus' hellish temperature were belched into the planet's atmosphere over time through erupting volcanoes.

Noack and her colleagues examined the interaction of carbon dioxide and other greenhouse gases in Venus' atmosphere and conclude that the planet may have been even hotter than it is today, Noack said.

"But at a certain point this process turned on its head – the high temperatures caused a partial mobilization of the Venusian crust, leading to an efficient cooling of the mantle, and the volcanism strongly decreased," Noack said. "This resulted in lower surface temperatures, rather comparable to today's temperature on Venus, and the mobilization of the surface stopped."

Noack and co-author Doris Breuer built a one-of-a-kind Venus computer model in which the planet's hot atmosphere was paired with a 3-D model of the interior.

Unlike on Earth, Venus' high temperatures have a much bigger effect on the rocky surface, which ultimately loses its insulating qualities, the researchers said.

"It's a little bit like lifting the lid on the mantle: The interior of Venus suddenly cools very efficiently and the rate of volcanism ceases," Noack said. "Our model shows that after that 'hot' era of volcanism, the slow-down of volcanism leads to a strong decrease of the temperatures in the atmosphere."

Their models also suggested differences in the time and place in which the volcanoes resurfaced Venus over time.

So even as Venus' atmosphere cooled, there would remain a few active volcanoes which resurface some spots with lava flows, researchers said. In fact, some of these volcanoes might be active even today, according to recent results from the European Space Agency's Venus Express mission.

Venus Express launched in 2005 and arrived at the cloud-covered planet a year later. The spacecraft recently detected 'hot spots' on Venus, or areas of unusually high surface temperatures, at volcanoes that were previously thought to be extinct.

Source: www.space.com

College Students Help Develop Small Satellite with Big Plans

Satellites are big. They cost a lot of money. At least that's the impression a couple of University of Maryland-College Park students had when they applied for an internship to help construct a satellite instrument with scientists at the NASA Goddard Space Flight Center in Greenbelt, Md. As the pair quickly discovered, nothing could have been farther from the truth.

To their astonishment, the satellite that Saman Kholdebarin and Lida Ramsey helped to develop was literally the size of a football. "I had no idea you could make these satellites so small," Kholdebarin said, recalling his surprise when his Goddard mentors explained the project to him. "I was astounded."

The small satellite, with a big mission, is appropriately named "Firefly." Sponsored by the National Science Foundation (NSF), the pint-sized satellite will study the most powerful natural particle accelerator on Earth — lightning — when it launches from the Marshall Islands aboard an Air Force Falcon 1E rocket vehicle next year. In particular, Firefly will focus on Terrestrial Gamma-ray Flashes (TGFs), a little understood phenomenon first discovered by NASA's Compton Gamma-Ray Observatory in the early 1990s.

Mystery Flashes

Although no one knows why, it appears these flashes of gamma rays that were once thought to occur only far out in space near black holes or other high-energy cosmic phenomena are somehow linked to lightning.

Using measurements gathered by Firefly's instruments, Goddard scientist Doug Rowland and his collaborators — Universities Space Research Association in Columbia, Md., Siena College, located near Albany, N.Y., and the Hawk Institute for Space Studies in Pocomoke City, Md. — hope to answer what causes these high-energy flashes. In particular, they want to find out if lightning triggers them or if they trigger lightning. Could they be responsible for some of the high-energy particles in the Van Allen radiation belts, which damage satellites? Firefly is expected to observe up to 50 lightning strokes per day, and about one large TGF every couple days.

"The fact that they exist at all is amazing," said Rowland, who spearheaded the overall effort. "They shouldn't exist."

The first hurdle to solving the mystery was building the spacecraft and its two experiment packages — all for the budgeted amount of less than one million dollars, which is about 100 times less expensive than what full-sized satellite missions normally cost. With help from about 15 students from the University of Maryland-College Park, Siena College in Loudonville, N.Y., and other universities, Rowland and the Firefly team designed and integrated the spacecraft and its instruments. The team expects to ship the completed satellite to the Air Force sometime this fall in preparation for a March 2011 launch. Once deployed in its low-Earth orbit, Firefly will provide at least three months of data, with a goal of up to one year to maximize student involvement in operations and data analysis.

Bittersweet End

Work began on Firefly in 2008 shortly after NSF selected the mission concept for support under its CubeSat program, which launches mini satellites as stowaways aboard rockets carrying larger satellites in space, rather than requiring dedicated rocket launches. Firefly represents the second in a series of NSF-sponsored small satellites designed to study Earth's upper atmosphere.

"We really are doing cutting-edge science," said Al Weatherwax, a Siena College professor who partnered with Rowland to win the NSF grant to develop the Firefly mission. "We got the right people and it worked out great. This is the most fun I've had. I'll be sad to see it end. We're already talking about our next bunch of CubeSats."

Under the two-year collaboration, the Hawk Institute for Space Sciences provided the spacecraft, ground station testing, and flight software.

Siena College built a number of spacecraft components, including one of Firefly's two experiment packages, the Very Low Frequency (VLF) receiver/photometer experiment. This experiment combines multiple sensors to measure both VLF radio waves and optical light emitted by lightning. These measurements will corroborate the occurrence of lightning when the spacecraft observes gamma-ray flashes. "As a college, we are able to take advantage of educational discounts," Weatherwax said, explaining how his team accomplished its assignment on a shoestring budget. "Commercial vendors either donated or reduced the price of key components."

And the Goddard team built Firefly's Gamma-Ray Detector (GRD) instrument, which will measure the energy and arrival times of incoming X-ray and gamma-ray photons associated with TGFs. Although Goddard scientist Joanne Hill designed the instrument, she assigned Ramsey and Kholdebarin the task of designing, building, and testing the instrument's power supply board, a component that monitors voltage levels that run the detector. David Guzman, a Ph.D. student from the Universidad de Alcalá in Madrid, Spain, meanwhile, was tasked with applying his knowledge of computer microprocessors to possibly enhance the instrument's performance.

Experience: A Confidence Builder

he experience was a memorable one for the trio. Both Ramsey and Kholdebarin agreed that their electrical-engineering classes taught them the basics of circuit electronics, but they learned through trial and error that it takes more than textbook knowledge to build a satellite component. Under certain applications, one circuit might work better with another, Kholdebarin discovered.

"After doing this, I've become more confident," Ramsey added. "I can figure out anything after this. That's the best experience. You really can do a lot more than you think you're capable of."

As for Guzman, who worked for the European Space Agency before beginning his graduate studies a few years ago, the project has revealed this much: "I hope to do a CubeSat in Spain some day."

Source: www.nasa.gov

Earth to Have Closest Encounter With Jupiter until 2022

Been outside at midnight lately? There's something you really need to see. Jupiter is approaching Earth for the closest encounter between the two planets in more than a decade--and it is dazzling.

The night of closest approach is Sept. 20-21st. This is also called "the night of opposition" because Jupiter will be opposite the sun, rising at sunset and soaring overhead at midnight. Among all denizens of the midnight sky, only the moon itself will be brighter.

Earth-Jupiter encounters happen every 13 months when the Earth laps Jupiter in their race around the sun. But because Earth and Jupiter do not orbit the sun in perfect circles, they are not always the same distance apart when Earth passes by. On Sept. 20th, Jupiter will be as much as 75 million km closer than previous encounters and will not be this close again until 2022.

The view through a telescope is excellent. Because Jupiter is so close, the planet's disk can be seen in rare detail--and there is a lot to see. For instance, the Great Red Spot, a cyclone twice as wide as Earth, is bumping up against another storm called "Red Spot Jr." The apparition of two planet-sized tempests grinding against one another must be seen to be believed.

Also, Jupiter's trademark South Equatorial Belt (SEB) recently vanished, possibly submerging itself beneath high clouds. Researchers say it could reappear at any moment. The dramatic resurgence would be accompanied by a globe-straddling profusion of spots and cloudy swirls, clearly visible in backyard telescopes.

And what was that flash? Amateur astronomers have recently reported a surprising number of fireballs in Jupiter's atmosphere. Apparently, many small asteroids or comet fragments are hitting the giant planet and exploding among the clouds. Researchers who have studied these events say visible flashes could be occurring as often as a few times a month.

Finally, we mustn't forget the moons of Jupiter because they are also having a close encounter with Earth. These are planet-sized worlds with active volcanoes (Io), possible underground oceans (Europa), vast fields of craters (Callisto), and mysterious global grooves (Ganymede). When Galileo discovered the moons 400 years ago, they were no more than pinpricks of light in his primitive spy glass. Big, modern amateur telescopes reveal actual planetary disks with colorful markings.

Source: www.nasa.gov

Space Shuttle Discovery Set for Last Trip to Launch Pad

Space shuttle Discovery is set to make one last trip to the launch pad late Monday (Sept. 20) to gear up for its final mission as NASA moves closer to retiring its orbiter fleet for good.

The shuttle is slated to begin the hours-long launch pad trek at 8 p.m. EDT (0000 GMT) tonight at NASA's Kennedy Space Center in Cape Canaveral, Fla. Hundreds of NASA workers and their families are expected to be on hand to watch the shuttle's move.

"It's a small way to give back to the people who have given so much to the space shuttle program over the years," NASA spokesman Allard Beutel told SPACE.com. "It's also a way for people to show their families all their hard work. This is where they've been spending all the hours of their time."

Kennedy Space Center workers and their families will have the opportunity to take pictures of Discovery, as the shuttle rolls out of the Vehicle Assembly Building during the short trip to the seaside Launch Pad 39A. Astronauts from Houston will also be present to answer questions from the crowd.

"A lot of these people have worked on the shuttle program for years but have never had the chance to take a picture in front of it," Beutel said.

The shuttle received a similar reception on Sept. 9, when NASA moved the orbiter from its hangar to the Vehicle Assembly Building to be attached to its external tank and twin solid rocket boosters.

Discovery is scheduled to launch Nov. 1 on an 11-day mission to the International Space Station that will mark the spacecraft's final trip to space. The mission, STS-133, will be Discovery's 39th spaceflight and is expected to deliver a storage room to the International Space Station along with a humanoid robot assistant for the outpost's astronaut crew.

NASA will retire the three remaining shuttles in its fleet – Discovery, Atlantis and Endeavour – next year to make way for a new plan aimed at sending astronauts to visit an asteroid by 2025. Discovery is the oldest of NASA's space shuttles.

Only two more shuttle missions are currently scheduled, including Discovery's November flight, before the reusable orbiter is retired. The shuttle Endeavour is slated to fly the final shuttle mission in February 2011.

Congress is discussing the possible addition of one extra mission to be flown by Atlantis sometime next year. The Senate has already approved the additional flight, but the measure has yet to pass through the House.

Source: www.space.com

A Night With the Moon: Skywatchers Savor Lunar Views In Global Event

MOFFETT FIELD, Calif. — At first it seemed like rain would spoil everything. But despite early threats of foul weather, the clouds parted right on time and 8-year-old Alexandra Chin – along with hundreds of other skywatchers – took a long, deep look at the moon on Saturday (Sept. 18).

"It looks even closer when you get to see the craters," Alexandra said.

Chin and her family were just a few of the 500 people who turned out here at NASA's Ames Research Center to peer through telescopes, picnic on the grass and listen to talks about the moon during the first International Observe the Moon Night, a global skywatching event to spur public interest in the moon with almost 400 venues scheduled in 30 different countries.

"This is fantastic," said Sandra Chin, Alexandra's mother. She had brought her three children to the Ames center from nearby Foster City to see the moon. "The kids are amazed. They're very surprised that they can see planets, not just the moon."

Alexandra and her siblings observed the moon through one of the 25 or so telescopes set up by amateur astronomers on a big patch of grass.

At Ames, in the heart of Silicon Valley, clouds hung around for much of the afternoon, threatening to cast a pall over the moon and the event. But the sky cleared around dusk, yielding brilliant views of the moon, Jupiter and Venus that were only occasionally spoiled by a white Farmers Insurance blimp cruising overhead.

The event's organizers were pleased with the turnout, especially since weather forecasts all week had predicted rain.

"Our local amateur astronomers came out, the public came out," said Brian Day, education and public outreach lead for NASA's Lunar Atmosphere and Dust Environment Explorer mission. "It really shows the level of interest here in the community."

The moon also did not disappoint skywatchers overseas. In the United Kingdom, Andrew Brown of Ashford, Kent, ventured outside, camera in hand, to gaze at the moon

"I was on my own, but still wanted to participate and [was] pleased the weather did cooperate," Brown said in an e-mail. "It is expected that rain will be arriving soon here."

Moon-watchers' delight

As darkness fell at Ames, skywatchers lined up at the telescopes, forming lines that in some cases were 40 people deep.

After children took their turn at the eyepiece, many ran about on the grass, blowing the whistle keychains that event organizers had handed out. The high-pitched din from hundreds of whistles, peeping intermittently but incessantly, sounded like a tree frog mating chorus, or an unhappy crowd at a European soccer match.

Those eager for some harder science wandered over to a floodlit patch of grass away from the telescopes, where researchers discussed recent discoveries about the moon. The speakers were David Morrison, former director of NASA's Lunar Science Institute; Barry Blumberg, a Nobel laureate and former director of the NASA Astrobiology Institute; and Greg Delory, deputy project scientist of the LADEE mission.

Dozens of people listened intently, though they sometimes had to strain to hear the scientists above the shrieking of whistles.

A lunar night out

The Ames Research Center was one of three NASA space centers that welcomed moon-watchers for the night of lunar appreciation in addition to the other events. NASA's Marshall Space Flight Center in Huntsville, Ala., and the Goddard Space Flight Center in Greenbelt, Md., also opened their doors.

"Everyone is getting a great look at the moon tonight," said Rob Suggs, manager of the Lunar Impact Monitoring Project at the Marshall Center. "I think for sure we'd like to do this again."

More than 250 people turned out to the U.S. Space & Rocket Center near the Marshall Space Flight Center to drink in views of the moon and listen to scientists discuss the latest lunar discoveries, such as the results from NASA's Lunar Reconnaissance Orbiter and others.

With a clear sky overhead, skywatchers got a clear view of the moon's famed Tycho crater and its tendrils of ray-like features, as well as Plato and Copernicus craters, Suggs told SPACE.com. NASA scientists also focused telescopes on the moon's terminator – the border between the illuminated and darkened parts of the moon as seen from Earth.

"A lot of people were surprised at how rough the terminator is because of the topography of the moon," said Barbara Cohen, a lunar scientist at Marshall, in an interview. "It's not like a smooth billiard ball."

At the Goddard Space Flight Center in Maryland, attendees got a chance to watch scientists fire lasers at the moon as part of an ongoing work to determine the precise location of the Lunar Reconnaissance Orbiter. Photos from the event showed visitors peering through telescopes, using touch displays to see pictures of the lunar surface and holding moon rocks.

The moon's appeal appears to have been growing lately among scientists and the public after a series of new international missions from the Japan, China, India and the United States.

"It seems to me that the moon is more of an international place," Suggs said. "It is not just for the U.S. or Russia. It's for everyone."

Source: http://www.space.com

Black Holes

Astronomers think the object shown in this Chandra X-ray Observatory image (in box) may be an elusive intermediate-mass black hole. Located about 32 million light-years from Earth in the Messier 74 galaxy (M74), this object emits periodic bursts of x-rays at a rate that suggests it is much larger than a stellar-mass black hole but significantly smaller than the supermassive black holes found at the centers of galaxies. Few such middling black holes have been discovered, and scientists aren't sure how they form.

Black holes are the cold remnants of former stars, so dense that no matter—not even light—is able to escape their powerful gravitational pull.

While most stars end up as white dwarfs or neutron stars, black holes are the last evolutionary stage in the lifetimes of enormous stars that had been at least 10 or 15 times as massive as our own sun.

When giant stars reach the final stages of their lives they often detonate in cataclysms known as supernovae. Such an explosion scatters most of a star into the void of space but leaves behind a large "cold" remnant on which fusion no longer takes place.

In younger stars, nuclear fusion creates energy and a constant outward pressure that exists in balance with the inward pull of gravity caused by the star's own mass. But in the dead remnants of a massive supernova, no force opposes gravity—so the star begins to collapse in upon itself.

With no force to check gravity, a budding black hole shrinks to zero volume—at which point it is infinitely dense. Even the light from such a star is unable to escape its immense gravitational pull. The star's own light becomes trapped in orbit, and the dark star becomes known as a black hole.

Black holes pull matter and even energy into themselves—but no more so than other stars or cosmic objects of similar mass. That means that a black hole with the mass of our own sun would not "suck" objects into it any more than our own sun does with its own gravitational pull.

Planets, light, and other matter must pass close to a black hole in order to be pulled into its grasp. When they reach a point of no return they are said to have entered the event horizon—the point from which any escape is impossible because it requires moving faster than the speed of light.

Small But Powerful

Black holes are small in size. A million-solar-mass hole, like that believed to be at the center of some galaxies, would have a radius of just about two million miles (three million kilometers)—only about four times the size of the sun. A black hole with a mass equal to that of the sun would have a two-mile (three-kilometer) radius.

Because they are so small, distant, and dark, black holes cannot be directly observed. Yet scientists have confirmed their long-held suspicions that they exist. This is typically done by measuring mass in a region of the sky and looking for areas of large, dark mass.

Many black holes exist in binary star systems. These holes may continually pull mass from their neighboring star, growing the black hole and shrinking the other star, until the black hole is large and the companion star has completely vanished.

Extremely large black holes may exist at the center of some galaxies—including our own Milky Way. These massive features may have the mass of 10 to 100 billion suns. They are similar to smaller black holes but grow to enormous size because there is so much matter in the center of the galaxy for them to add. Black holes can accrue limitless amounts of matter; they simply become even denser as their mass increases.

Black holes capture the public's imagination and feature prominently in extremely theoretical concepts like wormholes. These "tunnels" could allow rapid travel through space and time—but there is no evidence that they exist.

Source: www.nationalgeographic.com

Cosmic Pillars of Carina Nebula Dominate New Hubble View

A new photo from the Hubble Space Telescope shows huge pillars of hydrogen gas and dust in the Carina Nebula about 7,500 light-years from Earth.

The pillars are about 1 light-year tall, scientists say. That's nearly 6 trillion miles (9.7 trillion km), more than 60,000 times greater than the distance from the Earth to the sun. And the structures aren't giants by Carina standards: some of the nebula's pillars are three times as big. [Photo of Carina Nebula pillars.]

The columns, and the other odd shapes in the photo, are sculpted by violent stellar winds and radiation from the nebula's massive stars. The dense structures in the image may be nurseries, regions birthing new stars.

The Hubble telescope's new image is a composite of observations taken in 2005 of the region's hydrogen light and new observations of the area's atomic oxygen content.

The Carina Nebula is found in the constellation of the same name (Carina: the Keel). It spans about 100 light-years, making it four times larger than the famous Orion Nebula. Carina is a very bright nebula with intensive star-forming regions.

Carina has a powerful glow, which comes mainly from hot hydrogen basking in the strong radiation of monster baby stars. The immense nebula contains over a dozen stars with at least 50 to 100 times the mass of our sun. Such stars don't live very long — a few million years at most, compared to the sun's expected lifespan of about 10 billion years.

One of the universe's most impressive stars, Eta Carinae, is found in Carina. Eta Carinae is one of the biggest stars in the Milky Way. At more than 100 times the mass of the sun and about four million times brighter, it's the most luminous star known. Eta Carinae is highly unstable, and prone to violent outbursts, most notably a false supernova event in 1842.

The Hubble Space Telescope launched in April 199 and is still going strong 20 years later. To date, Hubble has observed more than 30,000 celestial targets and amassed more than a half-million pictures in its archive.

Source: www.space.com

Observe the Moon with the Rest of the Planet

Growing up in Staten Island, New York, there wasn't much night sky to see amidst the bright, orange-y glow of streetlights.

But when I was just a little girl, I got a small red telescope which we promptly pointed at the most obvious thing in the sky, the Moon.

Observing the Moon has been a part of human culture longer than any history can remember, and this great tradition continues this Saturday with International Observe the Moon Night.

InOMN has grown out of NASA's most recent missions to explore the Moon up close. The Lunar Reconnaissance Orbiter has been sending back loads of pretty pictures and gobs of new science about our nearest astronomical neighbor, and the folks at NASA hosted several outreach events. This year, they are taking the idea global, with hundreds of events where participants can observe and learn about the Moon.

Find an event nearest you using their map and listing. You can even host your own event!

Many of these events are doubling as "TweetUps" or meeting of Twitter users with a similar interest. Who says that new technology is isolating?! There is even a hashtag to follow for all the lunar goodness, #InOMN10.

Maybe you fancy your self a pretty good photographer? For several weeks, InOMN is having a photo contest with separate categories for beginners and those with more experience. Submissions for this end September 23rd! This one way to share your observations of the Moon with many people, no matter where they are.

Maybe you already have Saturday plans? Maybe you know you'll be at a wedding, for example, and can't make an official event? Grab some guests and head outside to gaze at the Moon together, even if just for a few minutes. Our planet's satellite is still full of surprises and beckons exploration. But maybe you just want to see a pretty sight, or explain why the Moon has phases, or why there just is no "dark side," at least permanently. No matter where you are, take advantage of the opportunity to share the Moon with friends and fellow astronomy enthusiasts!

Source : http://news.discovery.com

Food for Mars: A Daunting Challenge

Most people find the palatability of in-flight entrees an oxymoron. But even frequent fliers seldom encounter more than a few such meals per week. Astronauts, in contrast, may have to survive months in orbit dining on a really limited menu of processed foods and reconstituted beverages served from oh-so-glamorous plastic pouches. Luckily, even the International Space Station can restock its pantry several times a year because these foods are relatively perishable. Which explains the problem NASA faces in planning for really long missions -- like a trip to Mars.

Astronaut foods may appear indestructible, but many crew favorites don't retain their nutrition or palatability for even a year, notes Michele Perchonok.

She should know. Perchonok manages not only NASA's advanced food technology program, but also the development and preparation of foods for Shuttle astronauts. At the Institute of Food Technology annual meeting, on July 20, she described NASA's limited larder.

Foods destined for Space Shuttle missions must have a shelf life of a year, and 18 months if they'll be deployed on the International Space Station. Of the roughly 65 foods currently available for stocking spacecraft and deemed really palatable by NASA taste panels, 10 will lose their appeal within a year -- turning off-color, mushy or tasteless, she reported. By the end of five years, Perchonok says, "we're down to seven items."

Moreover, she adds, "studies have shown that if the acceptability or the sensory properties degrade, so does the [food's] nutrition." Indeed, after one year, space food exhibits notable losses of vitamin A, folic acid (an important B vitamin) and thiamine (another B vitamin that plays a role in the body's use of carbs and certain building blocks of proteins). And nutrient losses don't end there, Perchonok says. "Basically, after one year, we are out of vitamin C."

Sure, NASA could supply astronauts with multi-vitamin pills. But that's no panacea, Perchonok observes, since preliminary studies by NASA have shown that the potency of vitamins diminishes faster in pills than it does in foods.

Clearly, she says, these food-nutrient losses are "pretty serious." So if NASA wants to be able to stock a spacecraft for Mars travel, "we've got a problem."

Using current propulsion systems, the space agency has to plan on it taking between 6 and 8 months to travel each way to Mars, Perchonok explains. Since Mars and Earth come close to each other only once every other year, crews "will have to stay on the surface for 18 months" before returning home, she adds.

Because glitches may arise or crews may be asked to help stock a Martian pantry for followup visitors from Earth, NASA's goal is the development of foods that will remain both safe and appetizing for at least five years.

Canned goods have a good shelf life, but can't be heated in microwaves -- and are considerably heavier than the pouches that astronaut food is dispensed in today. And weight is a big issue. It constitutes about 15 percent of the payload of food, which is expected to weigh 9,660 kilograms (10.6 U.S. tons) for a crew of 6 heading out to Mars.

To keep the weight down, foods are eaten in their packaging. And today's foil-lined pouches tend to work well when conventionally heat sterilized -- but can delaminate when their contents are subjected to "pressure assisted" thermal sterilization, a new technique being developed by C. Patrick Dunne of the Army's Natick, Mass.-based Soldier R&D Center and his colleagues. Dunne's consumers are military troops sent into the field with rations packaged as meals ready to eat, or MREs. (Dunne's innovative pressure-assisted sterilization helped him win selection as an IFT research fellow, last year.)

MREs must have a shelf life of three years at 26 °C, Dunne reported at the IFT meeting, last week. And though the experimental pressure-assisted sterilization system he reported on is slow (able to sterilize just 10 MREs per half hour), he expects the technology eventually can be scaled up to a continuous processing of 50 pouches per minute.

The new technology's real benefit is taste, he noted. A salmon fillet in Alfredo sauce processed with the new pressure-assisted technology not only tastes yummy, he says, but also "looks like a salmon that was poached -- not like cat food."

Taste is a particularly pivotal issue for astronaut food: Crews need to eat every bite of what they open up. Crumbs from cookies or crackers can make a mess and eventually get into someone's eyes, Perchonok says. Wet foods that aren't completely gobbled up will eventually go bad and stink up a spacecraft. Which can become especially nasty since astronauts don't take out the trash every day but bring it back home with them or hold it for months until they can pack it into a craft that is destined to travel towards Earth's surface (but actually incinerate in the atmosphere).

Bottom line, Perchonok says: NASA needs new ideas for light-weight, very air-tight flexible food packaging that can seal in freshness and sterility for at least three years. Luckily, there should be ample time to find such alternatives since travel to Mars is still many years away, Perchonok says: "Probably 2035 at the earliest."

Astrological Scene Found on Egyptian Tomb Ceiling

Brightly painted astrological scenes have emerged on the ceiling of an ancient Egyptian tomb, according to a statement released on Wednesday by the Supreme Council of Antiquities.

The scenes, which include a depiction of the sky goddess Nut, have been found in the burial chamber of a Nubian priest in the el-Asasif area on the west bank of Luxor.

"The chamber was found at the bottom of an eight meter deep burial shaft,” Zahi Hawass, Secretary General of the Supreme Council of Antiquities (SCA), said.

The room is in very good condition and contains beautiful painted scenes in vivid colors. Blue and yellow dominate the ceiling, as the goddess Nut welcomes with raised arms the body of the deceased.

Named Karakhamun was a priest who lived during the 25th dynasty (755-656 B.C.). His tomb, known as TT223, was first discovered in the 19th century, but then it collapsed and disappeared under the desert sands.

It was rediscovered by an Egyptian-American expedition in 2006. In addition to the tomb of Karakhamun, the team is also working on two other neglected Nubian tombs nearby: the tomb of Karabasken, the Mayor of Thebes, and the tomb of Irtieru, the Chief Attendant to the Divine Consort of Amun, Nitocris.

Described by 19th-century travelers as some of the most beautiful Theban tombs, the burials were wrongly believed to have been completely destroyed. In fact, they were all rediscovered four years ago.

“Their painted ceiling, stunning relief, and elegant architecture are not obliterated, merely hidden beneath layers of soot, veiled by dust and cobwebs, and blocked by piles of debris,” team leader Elena Pischikova, director of the South Asasif Conservation Project (ACP), wrote on the project’s website.

According to Pischikova, Karakhamun’s tomb is possibly the largest in the necropolis. However, when the ACP team found the burial, it was barely visible and totally inaccessible. Almost hidden beneath the sand, the only trace of its location was a blackened crack in the bedrock.

“Some days of tedious digging soon yielded much more than we could have hoped for – a wall of carving, almost completely intact, with a life size figure of Karakhamun in front of an offering table,” Pischikova said.

Little is known of the priest, who remains the most enigmatic figure in the necropolis. Karakhamun did not appear to hold any important administrative position and his priestly title wasn’t particularly important.

Yet his tomb, featuring two pillared halls, paintings and exquisite relief carvings, was one of the most beautiful in the necropolis.

According to the ACP researchers, “he must have had close connections to the royal court or the royal family itself.”

"Further exploration of the tomb must shed more light on its date and the identity of Karakhamun himself," the archaeologists wrote.

Photo: Courtesy of Supreme Council of Antiquities

Source: http://news.discovery.com

Snake Robots Could Disable Explosives

Snakes can creep and they can crawl, but they're not very good at defusing bombs or going on search-and-rescue missions. Snake robots, however, might be a different story.

In a project called the Robotic Tentacle Manipulator, engineers at the U.S. Army Research Laboratory are developing snake-like autonomous robots that can go into dangerous situations in place of live soldiers to aid in search and rescue missions and to inspect potential threats from Improvised Explosive Devices, or IEDs.

That type of explosive has been a major source of headaches for the military in Iraq and Afghanistan, which at times has been responsible for half of U.S. military deaths in the region. Instead of sending soldiers into harm's way to find and deactivate these explosives, snake robots would do the job.

These snake robots are equipped with electronic sensors, laser detection and ranging called LADAR, which renders 3-D images of object shapes and physical properties. Touch sensitive sensor allows the bot to feel, balance and rotate objects.

Such robots have several advantages over other kinds of robots because:

* They are scalable, meaning they can be built big or small.
* They can travel over rough terrain or climb stairs. One of the researchers, Derek Schererer, says in a press release, "Consider that snakes push off rocks or roots to propel their bodies. We are using this same concept in development."
* Several snakes in one area can work as a team to scan a room or manipulate an object.
* And they may be able to solve the persistent "opening a door" problem, which is exactly what it sounds like: robots can't open doors. But high levels of articulation in the snake robot could prove to be effective for grasping and rotating different types of door handles.


Autonomous robots being able to communicate with each other is a major area of research. I just wrote about how researchers are developing underwater robots that can communicate with each other to accomplish a single mission.

Source: http://news.discovery.com

I am Iron Man: Top 5 Exoskeleton Robots

Everyone has wished, at one point or another, that they had the strength to lift a car off of the ground, or break through a brick wall with the pound of a fist. You know, typical superhero stuff. But everyone who has tried it knows that most of the time reality, and the limits of the human body, spoil the fun.

Thankfully, scientists have been developing a way around those limits, in the form of wearable exoskeleton robots capable of increasing our strength, stamina and speed.

These aren't the massive, clunky brutes of old sci-fi movies, but nimble extensions of the human body with the gift of intelligence. They work by sensing and anticipating the movements of the person wearing the suit, using their own power to minimize the efforts of the user.

While most of us probably won't be living out our superhero (or evil villain) fantasies, these robots have some very practical applications, both military and civilian.

Here are the top five exoskeleton robots that stretch the limitations of our bodies and our imaginations.

1. Raytheon Sarcos Exoskeleton
Designed primarily with military purposes in mind, the XOS Exoskeleton, developed by Sarcos (purchased by Raytheon Integrated Defense Systems in Massachusetts), is the robot perhaps most like the popular comic book character Iron Man. While it doesn't shoot missiles or have boots with rocket thrusters in them, it does allow the wearer to lift or carry up to two hundred pounds repeatedly without tiring. It's unique because it's one of the few full-body exoskeleton robots available. Most robot exoskeletons are broken up into either legs or arms.

The idea is that a soldier wearing one of these robots could carry heavy gear over long distances without getting tired; rescue wounded soldiers from the battlefield with ease; or singlehandedly wield a weapon that usually requires two people to operate.

The major challenge has been engineering a power source that will power the robot from four to 24 hours. Right now the Exoskeleton can't operate that long without being plugged into some external power source, but the engineers are working on making it completely self sustaining.

2. Human Assistive Limb Exoskeleton (HAL)
Want to look your best for a big night on the town? CYBERDYNE Inc. in Japan understands. For those of you obsessed with accessories, this robot is a little more wearable than the others. The Human Assistive Limb Exoskeleton, or HAL, is a "cyborg type" robot designed to help people with mobility problems, in rehabilitation, and for heavy lifting. Although, if you visit the company's Web site, at first glance it looks as if the robot is designed to help you become a kung-fu master.

HAL isn't all aesthetics though. It also has brains and beauty. In one sense HAL is a mind reader, as it uses electrical signals sent to muscles from the brain to anticipate the wearer's movement. It then calculates how much power the user intends to produce and directs the right amount to the right joints on the exoskeleton. HAL's ability to anticipate movement allows it to move fractions of a second before you do, providing seamless interaction between human and robot. And with its clean, sleek design you'll be the bell of the robot ball.

3. Human Universal Load Carrier (HULC)
Like the Raytheon Sarcos Exoskeleton, the Human Universal Load Carrier (HULC) was designed to create a stronger, more durable soldier. Developed by Berkley Bionics in Berkley, Calif., the HULC is a wearable robot exoskeleton for the legs. It enables the user to carry up to two hundred pounds on his or her back over long distances and harsh terrains.

While the HULC is not a full body exoskeleton like the Raytheon Exoskeleton, it does provide one distinct advantage: the HULC is the only wearable exoskeleton proven to reduce the user’s oxygen consumption, giving the soldier greater stamina.

The HULC weighs 53 pounds and is battery powered, but can be equipped with a generator that lasts for three days. The only problem: the generator weighs 85 pounds, a big chunk of the robot's carrying capacity.

4. Honda Experimental Walking Assist Device
Saddle up boys and girls, it's time for a new breed of walking horse. The Honda Experimental Walking Assist Device is a robot exoskeleton for the legs, designed to reduce the strain of walking for the elderly and those with mobility problems.

Essentially a chair with legs, the Honda exoskeleton allows users to sit down in a saddle-like seat and strap their feet into two shoes attached to artificial limbs. The seat supports a portion of the wearer's body weight, reducing the strain to joints in the knees, ankles and hips.

While the device is expected to improve mobility, running a marathon in one probably isn't a good idea, since the lithium ion battery (a more powerful version of the cell phone battery) lasts roughly two hours at a pace of 2.8 miles per hour.

5. MIT Exoskeleton
Designed to use less power and weigh less than similar robotic devices, the exoskeleton developed in Cambridge, at the Massachusetts Institute of Technology, is another wearable robot for the lower body. The purpose of the exoskeleton is to help people with heavy loads to carry on their backs (hikers, soldiers, students with too many physics textbooks) lighten the load.

Unlike other robotic exoskeletons, which can require up to 3,000 watts to power, the MIT exoskeleton only requires one watt. However, the device does interfere with the wearer's normal walking motion, which causes the user to expend more oxygen than he or she would without the device.

Source: http://news.discovery.com

Moon's Face Reveals Extreme Cosmic Abuse

The moon's pimpled face is a testament to the serious beating it's received over the years from incoming space rocks, and a new study has found just how severe that lunar smackdown has been.

Scientists have compiled the first comprehensive catalog of large craters on the moon to document its cosmic abuse. They've also made a detailed study of minerals on the moon and identified areas of unusual silica-rich composition, in a pair of related studies.

The new findings are detailed in threepapers in the Sept. 16 issue of the journal Science.

Mapping the holes

In a second study, scientists built a new lunar crater map with data from the Lunar Orbiter Laser Altimeter instrument on NASA's Lunar Reconnaissance Orbiter,which includes 5,185 craters that are 12 miles (20 km) in diameter or larger.

The database provides a window on the past, revealing which parts of the moon are most pockmarked, and therefore represent older surfaces, and which areas have been covered over with fresh material by volcanism relatively recently. The researchers discovered that the moon's oldest regions are the southern near side and the north-central far side.

One feature, the South Pole-Aitken basin, appears to be the oldest basin on the moon. As such, it could offer unique clues about the moon's history, and the story of the early solar system in general.

The findings "are telling us something about the infancy of the solar system," said the study's leader James W. Head III, a planetary geologist at Brown University, in a statement. "It is clear we can find out and learn so much more from future missions, robotic or otherwise. There is so much to do."

Rare moon minerals

Researchersused the Diviner Lunar Radiometer Experiment, also on the Lunar Reconnaissance Orbiter, to measure the infrared light coming from the moon in several frequencies. Long-wavelength infrared light is heat energy, and it can give researchers information about some of the mineral content of the lunar surface not available from visual or other-wavelength observations.

In particular, the scientists looked for areas rich in silica (made of the chemical compound silicon dioxide), a type of rock that includes quartz and other formations. This compound is relatively rare on the moon, and requires a particular volcanic process for creation.

The team found five spots on the moon rich in silica, showing that this mineral does exist on the moon, but is indeed rare.

A third team of researchers, led by Timothy D. Glotch of New York's Stony Brook University, honed in on some of these spots and found that the silica on the moon is likely quartz, silicon-rich glass or alkali feldspar.

"The silica-rich materials have actually been proposed to be on the surface in these locations, but we have never sent an instrument that could detect them before," Greenhagen told SPACE.com. "It's important to know the silica-rich regions because they require a very specific type of crustal evolution."

"For the first time we're actually detecting how complex the lunar surface is," said planetary scientist Benjamin T. Greenhagen of NASA's Jet Propulsion Laboratory in Pasadena, Calif., leader of one of the mineralogy studies. "It's a bit of a paradigm shift." [See the new moon map]