'Old Faithful' Sunspot to Fire Off More Solar Flares, Scientists Say

An active region of the sun that blasted out powerful solar storms four days in a row last week likely isn't done yet, scientists say.
Officially, the flare-spouting region is called sunspot 1283. But space weather experts have dubbed it "Old Faithful," after the famous geyser in the United States' Yellowstone National Park that goes off like clockwork. And the solar Old Faithful should erupt again before it dissipates, researchers said.
"It still has a fair amount of complexity," said solar physicist C. Alex Young of NASA's Goddard Space Flight Center in Greenbelt, Md. "So we still have a pretty good chance of seeing some more stuff from this one." [Photos: Sunspots on Earth's Closest Star]
An active sunspot
Sunspots are temporary dark patches on the solar surface caused by intense magnetic activity. Some last for hours before disappearing; others linger for days, weeks or even months.
Powerful solar storms often erupt from sunspots. These include radiation-flinging solar flares and phenomena known as coronal mass ejections (CMEs) — massive clouds of solar plasma that can streak through space at up to 3 million mph (5 million kph).
From Sept. 5-8, sunspot 1283 produced four big flares and three CMEs. Two of the flares were X-class events and two were M-class flares. (Strong solar flares are classified according to a three-tiered system: X-class are the most powerful, M-class are of medium strength and C-class are the weakest.)
While the rapid motion previously observed in sunspot 1283 seems to have died down a bit, Young said, the sunspot looks poised to erupt again sometime soon.
"There's a good probability that we're still going to see at least another M-class flare, possibly another X-class flare," Young told SPACE.com.
It's not uncommon for sunspots to pop off a number of powerful flares in quick succession the way 1283 has done, he added. That seems to be the natural order of things.
"When you see one big flare, your chances of seeing another one are pretty good," Young said.
Learning more about solar storms
Solar flares directed at Earth can cause temporary radio-communication blackouts. CMEs have even greater destructive potential; they can spawn geomagnetic storms that disrupt GPS signals, radio communications and power grids. [Sun's Wrath: Worst Solar Storms in History]
So researchers are working hard to better understand sun storms, with the aim of one day being able to predict them with a great deal of accuracy and a long lead time. But they're not there yet.
"We still have a long way to go to really have the kind of forecasting capabilities that we have with terrestrial weather," Young said.
That's not to say scientists aren't making progress. Indeed, they've learned a lot about solar eruptions lately, Young said. And the knowledge base will continue to grow, he added, as a fleet of sun-watching spacecraft beam home more and more observations of Earth's star.
"We're really in a great time right now in terms of the data that we have," Young said, citing the contributions of spacecraft such as NASA's STEREO and Solar Dynamics Observatory, as well as SOHO, a collaboration between NASA and the European Space Agency. "It's going to be pretty exciting, from a solar physics and a space weather point of view."

All of these eyes on the sun should be treated to quite a show over the next several years. Solar activity has been ramping up over the last few months as the sun works toward a maximum in its 11-year activity cycle.

Scientists expect the peak of the current cycle, which is known as Solar Cycle 24, to come in 2013.

Confirmed! Scientists Tally Over 600 Alien Planets

For anyone keeping track, the number of confirmed alien planets now stands at more than 600, bolstered by the announcement today (Sept. 12) of 50 newfound alien worlds by the European Southern Observatory (ESO).

More than 50 new exoplanets — including one "super-Earth" that could potentially support life — were discovered using data from European observatory's High Accuracy Radial velocity Planet Searcher (HARPS) spectrograph, an instrument on the 11.8-foot (3.6-meter) telescope at the La Silla Observatory in Chile, ESO officials announced at the news briefing.
This bounty of alien planets is the latest in a string of discoveries that effectively pushed the current exoplanet tally past the 600 mark. Given the technological advances in the field of exoplanet research, it's possible we could see 1,000 confirmed alien worlds very soon, said Wesley Traub, chief scientist of NASA's Exoplanet Exploration Program at the Jet Propulsion Laboratory in Pasadena, Calif.
"The next big milestone should be 1,000," Traub told SPACE.com. "We are learning that there are so many planets out there, and many stars have multiple planets around then, that it's just a question of time until we get to that 1,000 mark of confirmed planets." [Gallery: The Strangest Alien Planets]
The search for alien worlds
NASA's planet-hunting Kepler space observatory has identified more than 1,200 planetary candidates, which are potential worlds that require more observation before they can either be confirmed as exoplanets or deemed false positives.
Kepler uses the transit method to sniff out potential alien planets. This method looks for changes in a star's brightness caused by a planet crossing in front of it. ESO's HARP spectrograph, on the other hand, uses a technique called radial velocity that looks for repeated fluctuations in a star's movement potentially caused by a planet's gravitational pull.
"As technologies get better, we are able to discover things that are smaller and have smaller signals, whether it's radial velocities or transits," Traub said. "People have always been looking for these small planets, but we're pushing really hard to make radial velocity work better so we can find something like Earth. That's basically the holy grail of radial velocity. The same thing is true about transits."
The European Southern Observatory's new findings include 16 super-Earths, which are potentially rocky worlds that are more massive than our planet. Astronomers are especially interested in one, called HD 85512 b, which was found to orbit at the edge of its star's habitable zone, a region where conditions could be suitable to support life. [Infographic: Alien Planet HD 85512 b Holds Possibility of Life]
And while the current tally of exoplanets stands at just over 600, there are some discrepancies in how people classify these alien worlds.
According to the Extrasolar Planets Encyclopedia, a database compiled by astrobiologist Jean Schneider of the Paris-Meudon Observatory, there are now 645 detected alien planets.
Yet, the Jet Propulsion Laboratory's PlanetQuest website, which keeps a count of confirmed alien planets, lists 564 planets (not including the ESO exoplanets announced today).
Candidates vs. confirmed planets
This discrepancy is largely because the criteria for what constitutes an exoplanet can differ, based on the website or organization.
"If you look at the European site (Extrasolar Planets Encyclopedia), it includes anything that has been announced," Traub said. "It's trying to be as complete a list as possible, so it will always have the maximum number of planets of the sites that list them. If something is announced, [Schneider] adds it on there. He's very, very attentive that way."
NASA's PlanetQuest site, however, takes a much more conservative approach. PlanetQuest tends to not add an exoplanet to the list until it has been validated, checked, and the study has been accepted for publication, Traub said.
"It's a very stringent set of requirements," Traub said. "The rule is, we don't want to have any mistakes, so we don't necessarily care if we're six months behind. We want to be sure of the number we're writing down."
As for the amount of exoplanet findings that have been announced within the past two years, Traub explained that it's likely due to the serendipitous timing of the Kepler data's release, and other exoplanet-hunting missions.
"It's largely because of the accidental confluence of when Kepler was launched and when we're getting the data," Traub said. "Same with radial velocity. People are getting better and better at it with time. It's kind of an accident, but it's a wonderful accident."

Missions for Mars: What's for Dinner?

When NASA sends humans to Mars, it will have to overcome not only engineering challenges, but gustatory ones as well. In fact, providing a full, nutritious and varied diet for future Red Planet travelers could be one of the most difficult aspects of planning the trip, one NASA researcher said.

Future Mars explorers will likely have to grow some of their own food, and be much more involved in food preparation than astronauts on the International Space Station, said Maya R. Cooper, a senior research scientist at the Space Food Systems Laboratory at NASA's Johnson Space Center in Houston. Cooper presented her findings at the 242nd National Meeting & Exposition of the American Chemical Society in Denver on Aug. 28.

Astronauts on space shuttle missions and flights to the International Space Station currently get 3.8 pounds (1.7 kilograms) of food per day. At that rate, astronauts would need almost 7,000 pounds (3,000 kg) of food per person for a five-year round trip to Mars. And when launching spacecraft off the planet, each pound is costly. [Space Food Photos: What Astronauts Eat]

"That's a clear impediment to a lot of mission scenarios," Cooper said in a statement. "We need new approaches."
One possible solution is to fly a self-contained "bioregenerative system" to grow food during the trip to Mars. Plants in such a system would multitask, providing food and also serving as little oxygen factories, producing fresh air for the astronauts to breathe. The plants would also clean the air of carbon dioxide exhaled by crews, and could even purify water.
Plants selected to be grown in space would have to meet a number of qualifications. For one, they would need to have few inedible parts that would be wasted. They should also be hardy, compact, and able to grow with minimal tending.
NASA scientists have identified 10 candidate crops that seem to fit the bill for astronaut food: lettuce, spinach, carrots, tomatoes, green onions, radishes, bell peppers, strawberries, fresh herbs and cabbages.
Still, it won't hurt for future astronauts to have green thumbs.
"This scenario involves much more food processing and meal preparation than the current food system developed for the space shuttles and the International Space Station," Cooper said.

NASA researchers are also considering shipping some bulk commodities to Mars on a separate unmanned spacecraft ahead of the astronauts. The first of these missions could launch in the 2030s, a year or two before crews launch, to build up a cache of food that would be ready and waiting when the astronauts arrive on Mars.

Space Food Added to NASA Artifacts Menu for Schools

NASA began serving up samples of space food to U.S. schools and universities on Monday (Sept. 12), as a 'side dish' to its on-going offer of space shuttle heat shield tiles.

The "Space Food for Schools" program continues NASA's efforts to preserve the history of its recently retired space shuttle program while also inspiring the next generation of space explorers, scientists and engineers.

Approximately 350 of the three-piece meals — including an entree, a dessert and a drink — are being offered on a first come, first served basis to educational organizations that qualify. The space food, some of it freeze dried, is offered for demonstration use only,  "not for consumption," NASA warns on its website. [Space Food Photos: What Astronauts Eat in Orbit]

Although specific food choices are not identified as part of the offer, NASA's pantry during the 30-year space shuttle program has been stocked with shrimp cocktail, potatoes au gratin and spaghetti with meat sauce, among a variety of other dishes. Dessert selections on the shuttle included freeze-dried strawberries and off-the-shelf sweets such as candy-coated chocolates (otherwise known as M&Ms).

To drink, astronauts could pick from coffee or tea, as well as powdered juices (Tang in its many flavors).

Under a program similar to the food offer, NASA has been distributing surplus space shuttle heat shield tiles to U.S. schools since late last year. To date, "Space Shuttle Tiles for Teachers" has distributed 4,000 of the black-and-white ceramic squares. NASA still has 3,000 available for the asking.
More than 20,000 tiles were installed on each shuttle, and each tile was designed to survive 100 trips to space and back. Varying in thickness from 1 inch (2.54 cm) to 5 inches (12.7 cm), depending on the heating they were to encounter, the tiles shielded against temperatures as high as 2,300 degrees Fahrenheit during entry into the Earth's atmosphere.
The tiles offered to schools were never flown in space or installed on the shuttles, but were spares left over as the program came to an end.
Because both the food and tiles are government property, NASA must follow a "transfer protocol." While there is no charge for the artifacts themselves, qualifying schools do need to cover shipping and handling. "Tiles for Teachers" are offered for $23.40 while the "Space Food for Schools" carries a fee of $28.03.

NASA and the General Services Administration operate a website through which schools can apply for the food and tiles. Through the same website, NASA has been making thousands of other space artifacts available to museums, including the Smithsonian. To date, the space agency has offered about 29,000 items, out of which 3,000 have been requested by eligible organizations.

The space shuttle program came to an end Aug. 31, just over a month after its 135th and final mission landed back on Earth. NASA has awarded its remaining shuttle orbiters to museums while still retaining some of their components for possible use on future spacecraft to send astronauts to the asteroids, the moon and ultimately to Mars.

For more information and to apply to for the space food and shuttle tiles, eligible schools can visit NASA’s and the General Service Administration’s historic artifacts website.

    

Dead Satellite Will Fall to Earth By September's End, NASA Says

 

A defunct satellite poised to fall back to Earth will make its death plunge during the last week of September, NASA officials now say.

The spacecraft, an old NASA climate probe called the Upper Atmosphere Research Satellite (UARS), was decommissioned in 2005 and has been slowly losing altitude since. Soon, the 6 1/2-ton satellite will make a final uncontrolled plunge through Earth's atmosphere.

On Monday (Sept. 12), a NASA update stated that the satellite is now expected to plummet back to Earth during the last week of September. Previous estimates by NASA and the U.S. military, which is monitoring the hefty space junk, suggested the UARS satellite would fall sometime in late September or early October. [Photos: Space Debris & Cleanup Concepts]

While most of UARS' huge bulk will burn up during re-entry, some pieces are expected to survive. NASA insists these will pose little risk to civilians on the ground, although there is a chance debris could impact a populated area.

This video simulation of the UARS satellite crash by the analytical firm Analytical Graphics Inc., shows where the satellite orbits Earth.

NASA officials say there is a 1-in-3,200 chance that a piece of UARS satellite debris could strike and injure a person on the ground. The most likely scenario is that the satellite falls somewhere over an ocean.

"Earth is big, the satellite is small; the chance of it hitting a person is very, very small," said Victoria Samson, the Washington Office Director of the Secure World Foundation, an organization dedicated to the peaceful use of outer space. "While the idea of something coming at you from outer space is unnerving, there are a lot more realistic threats we should be concerned about. The actual impact to any person is fairly minimal."

At this point, NASA cannot confirm the exact trajectory or time of the UARS satellite's plunge, which depend on solar weather, variations in Earth's gravitational field, and the orientation of the satellite. However, as UARS' re-entry draws near NASA should be able to offer more precise predictions.

The space agency first announced the spacecraft's impending dive last week. Since then, experts have been able to refine their tracking of the satellite, and confirmed its present orbit.
"As of Sept. 12, 2011, the orbit of UARS was 145 mi by 165 mi (235 km by 265 km)," NASA officials wrote in a statement.
The bus-size satellite is about 35 feet (10.7 meters) long and 15 feet (4.5 m) wide. And while it's too soon to know where the pieces of UARS will fall, an analysis suggests they will likely scatter within an area of 500 miles (800 kilometers) length.  [Infographic: NASA's Falling UARS Satellite Explained]
The $750 million UARS spacecraft was launched in 1991 aboard NASA's space shuttle Discovery to study ozone and other chemical compounds in Earth's atmosphere. Since that time, international standards and best practices for dealing with a spacecraft's end of life have been put in place.

"Now, they have to save enough fuel to either put the satellite in a graveyard orbit or guide it back in" to Earth in a controlled manner, Samson told SPACE.com. "That wasn't actually standard operating procedure back then."

For that reason, uncontrolled re-entry of large spacecraft like UARS are rare, though not unheard of, Samson said.

    

Star Blasts Alien Planet With X-Ray Attack

A nearby star is drubbing its close-orbiting planet with a barrage of X-rays 100,000 times more powerful than what the Earth receives from the sun, a new study has found.

That intense, high-energy radiation is blasting about 5 million tons of matter from the gigantic planet into space every second, researchers said. They made the observations using NASA's Chandra X-Ray Observatory and the European Southern Observatory's Very Large Telescope in Chile.

"This planet is being absolutely fried by its star," said study lead author Sebastian Schroeter, of the University of Hamburg in Germany, in a statement. "What may be even stranger is that this planet may be affecting the behavior of the star that is blasting it." [Illustration and video of the planet-blasting star]

A nearby alien solar system
The star, which is located about 880 light-years from Earth, is known as Corot-2a. Optical and X-ray data suggest that Corot-2a is between 100 million and 300 million years old, meaning it's fully formed, researchers said.
The star's one known planet, called Corot-2b, was discovered in 2008 by the French Space Agency's Convection, Rotation and planetary Transits (Corot) satellite. Corot-2b is about three times as massive as Jupiter, and it orbits very close to its parent star — just 3 percent of the Earth-sun distance (which is 93 million miles, or 150 million kilometers).
The new Chandra observations show that the star is surprisingly active, with bright X-ray emission generated by powerful magnetic fields. Such strong activity is usually found in much younger stars, researchers said. [The Strangest Alien Planets]
The huge, close-in alien planet may be playing a role.
"Because this planet is so close to the star, it may be speeding up the star's rotation and that could be keeping its magnetic fields active," said study co-author Stefan Czesla, also from the University of Hamburg. "If it wasn't for the planet, this star might have left behind the volatility of its youth millions of years ago."
A companion star?
Other observations suggest that Corot-2a might have a stellar companion that orbits at about 1,000 times the Earth-sun distance. Instruments have not picked up an X-ray signal from this star — perhaps because it does not have a close-orbiting planet to kick it into high gear, researchers said.
Corot-2b appears to be unusually inflated for a planet in its position. That could be another result of the X-ray barrage, researchers said, but they're not sure yet.
"We're not exactly sure of all the effects this type of heavy X-ray storm would have on a planet, but it could be responsible for the bloating we see in Corot-2b," Schroeter said. "We are just beginning to learn about what happens to exoplanets in these extreme environments."
The results were published in the August issue of the journal Astronomy and Astrophysics.
      

Why Is the Harvest Moon Big and Red?

The Harvest Moon is the full moon nearest the date of the Autumnal Equinox. Orbiting Earth at a shallow angle to the horizon this time of year, the moon rises at around sunset for several days in a row. Over the course of these days, the seamless transition from sunlight to moonlight provides farmers with additional time to bring crops in — and at just the right time of year for the harvest.
But the Harvest Moon provides a treat for non-farmers, too: Hanging low in the sky, it sometimes appears deep yellow or orange or even a vibrant red.
Shortly after the Harvest Moon rises, light from it passes sideways through more atmosphere than does moonlight coming from overhead. Atmospheric particles tend to scatter moonlight's bluish components more than its reddish components, which are allowed to penetrate through to your eyes. The moon thus appears redder the more atmosphere it passes through. Its color is most dramatic on nights when the atmosphere is especially muggy or hazy. [Why Does the Moon Turn Red During a Lunar Eclipse?]
A low-hanging moon also appears larger than a high-flying one. This is a trick of the brain known variously as the moon illusion, or Ponzo illusion, which has been observed since ancient times but still has no generally accepted explanation. One possible cause of the moon illusion is that we're used to seeing clouds just a few miles above us, while we know that clouds on the horizon can be hundreds of miles distant. We might therefore perceive an object on the horizon as farther away no matter what it is, and because the moon on the horizon is the same size as it normally is overhead, we perceive it as being much larger.

'Game-changer' in evolution from S. African bones

This image released by the journal Science shows Lee R. Berger of the University …

  Two million-year-old bones belonging to a creature with both apelike and human traits provide the clearest evidence of evolution's first major step toward modern humans — findings some are calling a potential game-changer.

This image released by the journal Science shows the right hand skeleton of the adult …

An analysis of the bones found in South Africa suggests Australopithecus sediba is the most likely candidate to be the ancestor of humans, said lead researcher Lee R. Berger of the University of Witwatersrand in South Africa.

The fossils, belonging to a male child and an adult female, show a novel combination of features, almost as though nature were experimenting. Some resemble pre-human creatures while others suggest the genus Homo, which includes Homo sapiens, modern people.

"It's as if evolution is caught in one vital moment, a stop-action snapshot of evolution in action," said Richard Potts, director of the human origins program at the Smithsonian Institution. He was not among the team, led by South African scientists, whose research was published online Thursday in the journal Science.

Scientists have long considered the Australopithecus family, which includes the famous fossil Lucy, to be a primitive candidate for a human ancestor. The new research establishes a creature that combines features of both groups.

The newly studied bones were found in 2008 in the fossil-rich cave region of Malapa near Johannesberg. Berger's then 9-year-old son, Matthew, found a bone that was determined to belong to the child. Two weeks later Berger uncovered the fossils of the female.

The journal published five papers detailing the findings, including separate reports on the foot, hand, pelvis and brain of A. sediba.

Berger said the brain, hand and foot have characteristics of both modern and early pre-human forms that show a transition under way. It represents a bona fide model that could lead to the human genus Homo, Berger said.

Kristian J. Carlson, also at Witwatersrand, said the brain of A. sediba is small, like that of a chimpanzee, but with a configuration more human, particularly with an expansion behind and above the eyes.

This seems to be evidence that the brain was reorganizing along more modern lines before it began its expansion to the current larger size, Carlson said in a teleconference.

"It will take a lot of scrutiny of the papers and of the fossils by more and more researchers over the coming months and years, but these analyses could well be 'game-changers' in understanding human evolution," according to the Smithsonian's Potts.

So, does all this mean A. sediba was the "missing link"?
Well, scientists don't like that term, which Berger calls "biologically unsound."

This is a good candidate to represent the evolution of humans, he said, but the earliest definitive example of Homo is 150,000 to 200,000 years younger.

Scientists prefer the terms "transition form" or "intermediary form," said Darryl J. DeRuiter of Texas A&M University.

"This is what evolutionary theory would predict, this mixture of Australopithecene and Homo," DeRuiter said. "It's strong confirmation of evolutionary theory."

But it's not yet an example of the genus Homo, he said, though it could have led to several early human forms, including Homo habilis, Homo rudolfensis or Homo erectus — all considered early distant cousins to man, Homo sapiens.

These articles "force a rethinking of how traits are coupled together in human evolution," the Smithsonian's Potts said in an email from Kenya, where he is doing research.

"For example, in previous definitions of our genus, the leading edge in the emergence of Homo has been brain enlargement. The sediba bones show, however, that reorganization of the brain and pelvis typically connected with the evolution of Homo need not have involved brain enlargement," he noted.

"The more we learn about human evolution, the more we see that traits" that must have happened together could occur separately, Potts said.

For example, the study of the hand shows that major changes in the thumb usually associated with toolmaking "did not imply abandoning life in the trees. In the foot article, we're introduced to a unique and previously unknown combination of archaic and advanced traits in sediba," Potts explained.

The researchers reported that the fingers of A. sediba were curved, as might be seen in a creature that climbed in trees. But they were also slim and the thumb was long, more like a Homo thumb, so the hand was potentially capable of using tools, though no tools were found at the site.

The fossil provides the first chance for researchers to evaluate the function of a full hand this old, said Tracy Kivell of the Max Planck Institute for Evolutionary Anthropology in Germany. Previously, hand bones older than Neanderthals have been isolated pieces rather that full sets.

The heel bone seems primitive, the researchers said. Yet its front is angled, suggesting an arched foot for walking on the ground, and there is a large attachment for an Achilles tendon as in modern humans, they said.

The pelvis is short and broad like a human pelvis, creating more of a bowl shape than in earlier Australopith fossils like the famous Lucy, explained Job Kibii of the University of the Witwatersrand.

That may force a re-evaluation of the process of evolution because many researchers had previously associated development of a human-like pelvis with enlargement of the brain, but in A. sediba the brain was still small.

The name Australopithecus means "southern ape," and "sediba" means natural spring, fountain or wellspring in the local Sotho language.

After the bones were discovered, the children of South Africa were invited to name the child, which they called "Karabo," meaning "answer" in the local Tswana language. The older skeleton has not yet been given a nickname, Berger said.

The juvenile would have been aged 10 to 13 in terms of human development; the female was in her 20s and there are indications that she may have given birth once. The researchers are not sure if the two were related.

___

Online:

http://www.sciencemag.org

  

On ancient Susquehanna, flooding's a frequent fact

Lucy Mitchell looks at the high water level during flooding of the Susquehanna River …

 Early settlers called the Susquehanna River "a mile wide and a foot deep." It's just a folk saying, but it hints at the forces behind a river that is, in fact, exceptionally likely to flood.

And flooding it is, with record or near-record levels recorded along its path from New York state to Chesapeake Bay after a wet summer that included storms Irene and now Lee.

"The Susquehanna is one of the most flood-prone rivers in America," said Chris Duffy, a professor of civil and environmental engineering at Penn State University.

It's an especially shallow river, Duffy said, and that means big rainfalls can create floods rapidly. But another issue is what's underneath the water.

"Here, you encounter the bedrock pretty quickly," Duffy said, meaning that even floods won't quickly scour out deep spots. Upstream, the average river depth is only a few feet, and perhaps only 15 or 20 feet at the mouth.

In contrast, parts of New York's Hudson River are about 200 feet deep, and its shipping channel from New York City to Albany is maintained at a depth of about 32 feet, according to the U.S. Geological Survey.

The Susquehanna — which derives its name from the Susquehannock tribe that once lived in the area — is also one of the world's most ancient rivers, at about 200 million years old, Duffy said. It once flowed all the way to the ocean, but as sea levels rose its lower valley got submerged and became the Chesapeake.

The Susquehanna has flooded 14 times since 1810, according to the Susquehanna River Basin Commission — an average of every 15 years. And most of the communities in the basin have residents in flood-prone areas— 1,160 out of 1,400.

The worst flood in modern times was in 1972, when the remnants of Hurricane Agnes dumped biblical rains. Seventy-two people died, and damage topped $2.8 billion — about $14.3 billion in today's dollars, according to the river commission. So far, the current floods haven't been nearly as destructive.

Size is a factor in the river's propensity to overflow, too.
At about 450 miles long, the Susquehanna is the largest river in the eastern U.S. It drains a basin of more than 27,000 square miles containing more than 3.8 million people, according to Bucknell University, which estimates that floods cause an average of about $113 million in damage every year.

"It's just always been there," Duffy said of the flooding threat, so much so that many towns along its banks have been creating flood control structures, such as levees, for 100 or even 200 years.

And even with the current crisis, Duffy said that some communities have prepared well for such events.

"Wilkes-Barre has really taken care of business," he said.

But not all the changes have helped mitigate flooding, he said.

In the Colonial era, many tributaries had water-powered mills, and those may have helped control some of the water flowing into the river.

"Yes, we have done some major manipulation of environments" along the river, Duffy said, but many wetlands are still intact along the tributaries.

Weather experts note that the recent combination of Irene and Lee hitting the entire region with record rainfalls is bound to cause flooding.

    

Dead NASA satellite will soon plummet to Earth

  A dead NASA satellite will soon fall to Earth, but the space agency says there is very little chance that a piece of it will hit someone.

NASA says the 20-year-old satellite will probably fall sometime between late September and October. Pieces of it could land anywhere in the six inhabited continents in a worldwide swath from south of Juneau, Alaska, to just north of the tip of South America. NASA scientists estimate a 1-in-3,200 chance a satellite part could hit someone. Most of it will burn up after entering Earth's atmosphere.

The 6-ton (5.4-metric ton) Upper Atmosphere Research Satellite (UARS) ran out of fuel in 2005 and will fall uncontrolled out of orbit. Only about 1,200 pounds (544.32 kilograms) of metal should survive, NASA said.

This satellite is far smaller than the 135-ton (123-metric ton) Russian space station Mir, which fell to Earth in 2001 or the 100-ton (91-metric ton) Skylab that fell in 1979. Mir fell into the South Pacific, while Skylab hit the Indian Ocean and parts of sparsely populated western Australia. Because two-thirds of the Earth is ocean, space debris usually hits water

"Things have been re-entering ever since the dawn of the Space Age; to date nobody has been injured by anything that's re-entered," said NASA orbital debris chief Gene Stansbery. "That doesn't mean we're not concerned."

NASA now has a rule that the chance of any of its satellites hitting someone has to be more than 1 in 10,000. But UARS, which measured chemicals in the air, was launched in 1991 before that rule was adopted. The agency usually tries to put dead satellites into "a graveyard orbit" or steer them down to the ocean, Stansbery said. But there was not enough fuel in this one to fire engines that would move it to a higher orbit or steer it down safely.

The 1-in-3,200 odds of being hit pertain to any of the nearly 7 billion people on Earth. But any one individual's odds of being struck are about 1 in 21 trillion.

Space debris bigger than 5 tons (4.5 metric tons) does not often fall to Earth. But this will be the third time this year for something that big to reach Earth, according to Jonathan McDowell, a Harvard University astrophysicist who tracks objects in orbit.

The UARS satellite travels over a large band of Earth, avoiding only areas close to the poles. NASA calculates that when the satellite does fall it will scatter pieces over a 500-mile (800-kilometer)-wide region.

Stansbery said the agency doesn't know exactly when and where those will fall because it depends on the orientation of the satellite in the atmosphere, solar storm activity and other variables.

There probably is no hazardous material left in the falling pieces, but people should not touch any fallen satellite parts just in case, he said.

NASA will be tracking the satellite on a weekly and later daily basis until it falls.
___

Online

NASA's UARS satellite re-entry tracking site: http://www.nasa.gov/mission_pages/uars/index.html