A supermoon rises over West Yorkshire in the U.K. last year. // Photograph from Back Page Images/Rex Features/AP

Andrew Fazekas
for National Geographic News
Published May 3, 2012

On Saturday night, the full moon will be closer to Earth than at any other time this year, an occurrence that’s been labeled a supermoon.

Due to the moon’s egg-shaped orbit, there are times when our natural satellite is at perigee—its closest to Earth—and at apogee, its farthest.

The term “supermoon” was coined in 1979 to describe a full moon that coincides with perigee—something that happens about once a year, on average.

During this week’s perigee, the moon will be 221,801 miles (356,955 kilometers) from our planet, and that close approach will happen within minutes of the official full moon phase, which occurs at 11:35 p.m. ET.

"As a consequence, this translates into it appearing as much as 16 percent bigger and 30 percent brighter than other full moons of 2012—not a huge amount, but definitely noticeable," said Geza Gyuk, an astronomer at the Adler Planetarium in Chicago.

The moon’s proximity won’t have any major effects on our planet, according to astronomers, who hope to dispel fears that the looming lunar orb causes natural disasters.

"While we know that during new and full moons the tides are greatest—and if it’s in concert with a storm surge it might produce unusual flooding—there is no scientific evidence that earthquakes and other natural disasters are connected," Gyuk said.

"Supermoons have been happening for billions of years, and nothing particularly special occurs on these dates—except, of course, for a beautiful full moon."

Another Supermoon on the Horizon

For photo hounds, the most picturesque moments during Saturday’s supermoon will occur in the minutes after local sunset, as the full moon hovers above the horizon.

"What you should see is the moon rising, deeply colored and looming over the foreground objects," Gyuk said. (Related pictures: See how a lunar eclipse turns the full moon red.)

Because the size of the moon’s orbit varies slightly, each monthly perigee is not always the same distance from Earth.

In March 2011, for example, sky-watchers were treated to the closest supermoon in two decades, when the moon was a mere 221,565 miles (356,575 kilometers) from Earth.

And next month the full moon will again roughly coincide with perigee, albeit one that puts the moon a bit farther away, at 222,750 miles (358,482 kilometers), Gyuk said.

"The full moon will appear to be just half of one percent different in size," Gyuk said. "So if you miss this month’s supermoon, don’t worry, you can see it again when it is only one percent less bright."

(Source: National Geographic)

A killed 16-foot Burmese python in the Everglades was found with an adult deer in its belly this past fall. Photograph from South Florida Water Management District via AP

Christine Dell’Amore
National Geographic News
Published January 30, 2012

From rabbits to deer to even bobcats, invasive Burmese pythons appear to be eating through the Everglades’ supply of mammals, new research shows.

Since the giant constrictors took hold in Florida in 2000, many previously common mammals have plummeted in number—and some, such as cottontail rabbits, may be totally gone from some areas.

Scientists already knew from dissecting the 20-foot (6-meter) snakes that they prey on a wide range of species within Everglades National Park. (See a picture of a Burmese python that exploded eating an American alligator in the Everglades.)

But this is “the first study to show that pythons are having impacts on prey populations—and unfortunately those impacts appear to be pretty dramatic,” said study leader Michael Dorcas, a herpetologist at Davidson College in North Carolina.

"We started the study after we realized, Man, we’re not seeing a lot of these animals around anymore," Dorcas said.

But “when we did the calculations, we were pretty astonished.”

Burmese Pythons Causing “Severe Declines”?

For the study, Dorcas and colleagues conducted nighttime surveys of live and dead animals on roads between 2003 and 2011. Such numbers provide estimates of how many animals of a certain species are present in a given area.

The scientists compared these data with similar surveys conducted in 1996 and 1997.

Before 2000 it was common to see mammals such as rabbits, red foxes, gray foxes, Virginia opossums, raccoons, and white-tailed deer on roadways after dark, the team says.

But the 2003 to 2011 surveys—which covered a total of nearly 35,400 miles (57,000) kilometers of road—revealed “severe declines” in mammal sightings, according to the study, published this week in the journal Proceedings of the National Academy of Sciences.

Raccoon observations dropped by 99.3 percent, opossum by 98.9 percent, and bobcat by 87.5 percent. The scientists saw no rabbits or foxes at all during their surveys.

Also worrisome is what could be happening to species that were already rare—and thus more difficult to research, Dorcas noted.

For instance, it’s unknown whether the snakes are putting the squeeze on the Florida panther, a subspecies of cougar deemed endangered by the U.S. Fish and Wildlife Service.

But “it’s not unreasonable to assume that a really large python could consume a Florida panther,” he said—the snakes are known to eat leopards in Southeast Asia.

Impact of Everglades Mammal Decline Unknown

It’s difficult to predict how the decline in mammal populations will affect the Everglades, Dorcas said.

But some species may even benefit from the python’s big appetite, he said. For example, turtle numbers are often kept down by raccoons, which eat the reptiles’ eggs. Without as many raccoons, “we may be knee-deep in turtles in 20 years,” he quipped.

Whit Gibbons is a professor emeritus of ecology and head of outreach for the Savannah River Ecology Lab at the University of Georgia.

"My bet is that some of the mammals that have been affected will partially recover by managing to adapt or adjust," said Gibbons, who wasn’t involved with the study.

"It’s unlikely," he added, "that raccoons are going to go extinct in Florida."

But as long as pythons are there, the mammals won’t bounce back to their former levels, he said.

Meanwhile, some groups are mounting efforts to stem the spread of the Burmese python. The Nature Conservancy’s “Python Patrol,” for example, works to prevent the reptile from moving into the Florida Keys.

And on January 17 the U.S. Department of the Interior announced a new law banning importation and interstate transport of four species of invasive snakes, including the Burmese python.

"We have taken strong action to battle the spread of the Burmese python and other nonnative species that threaten the Everglades and other areas across the United States," Secretary of the Interior Ken Salazar said in a statement.

"There’s no single solution to this conservation challenge, but banning the importation and interstate transport of these invasive snakes is a critical step."

Pythons’ Invasion an Opportunity?

The University of Georgia’s Gibbons sees the snakes’ invasion as a chance for scientists to track what happens to the Everglades.

Though the ecosystem “may not collapse, it will likely change,” he said. “That change would be very worthwhile to monitor from a scientific standpoint.

"Maybe next time we could prevent changes we don’t want to happen."

Brian Handwerk
for National Geographic News
Updated November 3, 2011

With daylight saving time (also called daylight savings) about to end again, clock confusion is once again ticking away: When exactly does daylight saving time end? Why do we fall back? Does it really save energy? Is it bad for your health? Get expert answers below.

When Does Daylight Savings End in 2011?

For most Americans, daylight saving time 2011 ends at 2 a.m. on Sunday, November 6, 2011, when most states fall back an hour. Time will spring forward to daylight saving time again on Sunday, March 11, 2012, when daylight saving time begins again.

The federal government doesn’t require U.S. states or territories to observe daylight saving time, which is why residents of Arizona, Hawaii, Puerto Rico, the Virgin Islands, American Samoa, Guam, and the Northern Marianas Islands won’t need to change their clocks this weekend.

Where it is observed, daylight savings has been known to cause some problems.

National surveys by Rasmussen Reports, for example, show that 83 percent of respondents knew when to move their clocks ahead in spring 2010. Twenty-seven percent, though, admitted they’d been an hour early or late at least once in their lives because they hadn’t changed their clocks correctly.

It’s enough to make you wonder—why do we do use daylight saving time in the first place?

(Source: National Geographic)

Christine Dell’Amore
National Geographic News
Published September 29, 2011

Holy bat buzz, Batman—a new study shows the night flyers are the first known mammals with superfast muscles.

Found in some songbirds and snakes, superfast muscles in bats occur in the throat and enable a crucial hunting behavior: echolocation, in which the bat sends out sound waves and listens for echoes bouncing off prey.

As a bat closes in on an insect, the mammal emits more than 160 calls a second, a phenomenon called terminal buzz.

The discovery explains how bats release such rapid calls. “It’s really cool, because the muscles belong to this rare group, superfast muscles,” said study leader Coen Elemans, a biologist at the University of Southern Denmark.

But “at the same time, they also limit the bats.”

Though fast, the specialized muscles allow only a finite number of calls per second, Elemans pointed out. With even faster muscles, bats would benefit by making more calls per second, since each sound wave gives them more information about prey.

Batty Experiments

For the study, Elemans and colleague released individuals of a species called Daubenton’s bats in a large cage, where they flew toward mealworms that the researchers had hung on a string. The bats’ echolocation calls were recorded with a sophisticated microphone array.

The scientists measured when the bats were issuing calls, as well as when the echoes of those calls reached the bats’ ears.

The team had suspected that bat call rates may be limited by the need to process the calls’ echoes. That is: If a bat calls too soon, it won’t be able to hear the previous call’s echo and therefore will lose track of prey.

Each echo, though, hit the caller within about 2.5 milliseconds, yet the bats waited 6 milliseconds, on average, before making the next call—”a sea of time,” Elemans noted.

That means that the bats are physically incapable of making more calls per second, not because they’re deliberately waiting for echoes.

Next, the scientists removed superfast muscle fibers from some of the bats’ larynxes and measured the tissue’s mechanical performance by stimulating it with electricity.

The team found the bats’ laryngeal muscles—which determine call frequency by tensing the bats’ vocal folds—could power movements up to, but not beyond, 180 times a second. That’s exactly the rate at which bats call during terminal buzz.

Superfast-Muscle Evolution Still a Mystery

The discovery of superfast muscles in mammals may also help scientists disentangle the muscles’ evolution overall, Elemans said.

For instance, researchers will now be able to compare the bat genome with other genomes of superfast-muscled animals—such as songbirds and snakes—to figure out when and how the muscles evolved.

What’s more, Elemans suggests that the tracking boost afforded by terminal buzz helped bats flourish when they first evolved 50 million years ago.

"You need these buzzes to catch stuff," Elemans said. In addition to flight and "regular" echolocation, terminal buzz is "the third reason why they’ve been successful evolutionarily."

(Source: National Geographic)

Andrew Fazekas
for National Geographic News
Published September 15, 2011

Like the imaginary Star Wars world Tatooine, a new planet found 200 light-years away has two suns, astronomers announced today.

NASA’s Kepler spacecraft uncovered the new planet, dubbed Kepler 16b, as it transited—or crossed in front of—both its parent stars, causing the brightness of each star to dim periodically.

Kepler data first allowed scientists to see that the stars are what’s known as an eclipsing binary system—a pair of stars that orbit in such a way that they eclipse each other, causing them to dim, as seen from Earth.

Based on the eclipses, the team calculates that the binary stars are just 20 percent and 69 percent the mass of our sun.

Sometimes, however, the system’s overall brightness dipped even when the stars were not eclipsing each other—hinting at the presence of a third body orbiting the binary pair.

"By timing the stellar eclipses, we could determine how much the third body was perturbing the two inner stars," said study leader Laurance Doyle, an astronomer at the SETI Institute in Mountain View, California.

The extra, irregular dimming “turned out to be no stronger than a planetary gravitational pull would be.”

Next: An Earthlike Planet With Two Suns?

Kepler’s data suggest that the new planet is a Saturn-like gas giant without a solid surface.

Traveling on a nearly circular, 229-day orbit around both host stars, the planet lies outside the system’s habitable zone—the region where liquid water, and thus life as we know it, could exist.

In fact, the new planet likely receives about the same amount of sunshine as Mars, which means that, even if it had a solid surface, the world would be far too cold to support life.

Still, as on Tatooine, “from Kepler 16b one would see a double sunset, but with the stars shifting position [and moving in relation to each other] while setting.”

And while Kepler 16b may not have any sand dunes, it’s theoretically possible for Earthlike planets to exist in similar binary star systems—an arrangement that Doyle says may be quite common.

"I estimate that there may be about two million such systems in our galaxy," he said.

The new planet with two suns is described in this week’s issue of the journal Science.

(Source: National Geographic)

Apocalyptic Plume
Photograph by Ivan Alvarado, Reuters

A Lord of the Rings-worthy plume rises roughly six miles (ten kilometers) above Chile’s Puyehue volcano (map) Sunday. As of Monday, activity at the volcano appeared to have tapered off, according to Telam, Argentina’s government news agency.

Even so, danger remains. In a statement on website of the regional government of Los Rios, Chile, for example, Governor Juan Andrés Varas warned that ash and potentially poisonous volcanic gases are slowly rolling toward a nearby valley. “Fortunately, the valley doesn’t drop abruptly, so we have time to evacuate,” Varas was quoted as saying by CNN.