"Super Earth" May Really Be New Planet Type: Super-Io

Oceans of lava might bubble on its surface. Hot pebbles may rain down from the sky. But the extrasolar planet CoRoT-7b is considered to be the most Earthlike world yet found outside our solar system.

A recent study, however, suggests that Earth might not be the best basis for comparison. Instead, the authors argue, CoRoT-7b is the first in a new class of exoplanets: a super-Io.

Like Jupiter's moon Io, CoRoT-7b could easily be in the right kind of orbit to experience what's known as tidal heating, according to study co-author Rory Barnes of the University of Washington in Seattle.

On Io, tidal heating is a result of the crust being constantly deformed by the push and pull of Jupiter's gravity. This action generates enough internal heat to drive hundreds of active volcanoes—and the same could be true for CoRoT-7b, Barnes said.

But unlike Io, CoRoT-7b closely orbits a star, not a planet, so tides aren't its only source of heat. Based on previous observations, astronomers know that CoRoT-7b's surface is between 1,832 and 2,732 degrees Fahrenheit (1,000 and 1,500 degrees Celsius).

That's hot enough for there to be "ponds or possibly even oceans of magma," Barnes said. Scientists also know that the planet is tidally locked, which means that only one side ever faces the star.

"There could be volcanism on the back side of the planet," Barnes said. "It could be that on one side the surface is molten, and on the other side there's raging volcanoes."

CoRoT-7b was found using the French-led planet-hunting mission CoRoT, which looks for periodic dips in starlight caused by orbiting bodies passing in front of—transiting—a star, as seen from Earth.

When CoRoT-7b's discovery was announced in February 2009, astronomers hailed the world as the smallest exoplanet yet found orbiting a sunlike star. 

From CoRoT-7b's transits, astronomers could tell that the planet is about twice the size of Earth, which is approximately 7,920 miles (12,760 kilometers) wide. Io measures roughly 2,260 miles (3,630 kilometers) across.

Later studies measured CoRoT-7b's mass and density and confirmed that the planet is rocky. Based on these characteristics, CoRoT-7b was dubbed a super-Earth.

The term is one of a handful—such as "hot Jupiter" and "super-Neptune"—being used to informally classify exoplanets based on how closely they resemble worlds in our solar system.

In the recent study, presented last month at a meeting of the American Astronomical Society, Barnes and colleagues looked at the possible orbits for CoRoT-7b based on its size and mass, its proximity to its star, and its interactions with a nearby sister planet, CoRoT-7c.

The researchers found that even a slight eccentricity in CoRoT-7b's orbit would generate enough tidal heating to spawn bunches of volcanoes, making the planet much more Io-like than Earthlike.

For starters, just as Io circles close to massive Jupiter, CoRoT-7b orbits very close to its host star, so the influence of gravity is especially strong, Barnes said.

What's more, both Io and CoRoT-7b are tidally locked. In Io's case, this means that one side always faces Jupiter. That side of the moon is being tugged so much harder by gravity that the otherwise round world becomes slightly elongated, with a bulge around the middle.

"Earth does this—we have a tidal bulge due to interactions with the sun and our moon," Barnes noted. "The ocean tides are the result of [gravitational] tides, but rock is also distorted due to tidal effects."

In addition, Io maintains an irregular, elliptical orbit due to interactions with other Jovian moons close by, so its distance to Jupiter changes over time. As Io gets closer to Jupiter, it becomes more elongated, and as it moves away it becomes more spherical.

"If you had a tennis ball and you kept squeezing it, you would get heat from friction," Barnes said. "For Io it's like that, except you're doing it to a planet."

For now, CoRoT-7b is too distant to allow for current techniques and telescopes to accurately trace the planet's orbit, so whether the world truly resembles Io remains a mystery.

But "I think they have a pretty good case," said Rosaly Lopes, a planetary scientist with NASA's Jet Propulsion Laboratory in Pasadena, California.

After all, volcanism on Io had been predicted shortly before the Voyager spacecraft actually spotted the moon's volcanic plumes in 1979, she said. (See a picture of a giant plume on Io.)

"Stan Peale and colleagues ... analyzed the orbit of Io and said it would have tidal heating," Lopes said. The very next week, pictures from Voyager revealed about a dozen plumes, and later images from the Galileo spacecraft found more than 170 active volcanoes.

Peale, now a professor emeritus at the University of California, Santa Barbara, agreed that "the authors' conclusions are viable," noting that the presence of a second planet near CoRoT-7b means that the planet's orbit could vary "sufficiently to heat the interior to a super-Io state, leading to Io-like volcanic surface activity."

According to JPL's Lopes, "what's interesting here is that they're showing worlds like Io probably exist in other solar systems. But whether [CoRoT-7b] actually has active volcanism at the moment is going to be very difficult to prove."

It's possible spacecraft such as the Spitzer Space Telescope could see gases coming from CoRoT-7b's volcanoes, study author Barnes said.

"It might have a huge cloud of volcanic gases orbiting the planet. We could maybe see it in [light signatures] using Spitzer, but that would be very hard, because the planet is so far and so faint."

Overall, Barnes thinks similarly hot, rocky worlds will start turning up in the tens of hundreds as current planet-hunting missions such as CoRoT and the recently launched Kepler spacecraft peer deeper into the sky. 

"I think of Kepler as a super-Io detector," Barnes said. And each super-Io found will be "a stepping stone to finding real super-Earths."

Mercury Probe Searches for Vulcanoids, Spies Venus

That's the fundamental problem with vulcanoids, a hypothetical band of asteroids orbiting between the sun and the closest planet in, Mercury.

In fact, for years that was the problem with studying Mercury, since looking at the tiny planet through a backyard telescope is like trying to make out the patterns on a moth's wing as it sits on a football stadium floodlight.

Bigger telescopes on the ground or in Earth orbit can see the planet, but in doing so, glare from the sun would damage the instruments' sensitive lenses.

Even Hubble, capable of peering into the far reaches of the universe, can't safely look too hard at the innermost planet.

To really see details on Mercury, you need a spacecraft that gets close enough to keep the sun's glare out of the frame.

Mariner 10 gave humans our first good look at Mercury during a series of flybys in 1974 and 1975. But that mission was able to take pictures of just half the planet—we had to wait until January 2008 to see the other side!

Our first glimpse of Mercury's "hidden" face came via the MESSENGER mission, a spacecraft now swirling around Mercury in a gravitational dance that will eventually see the probe settle into orbit in 2011.

Along the way, MESSENGER has been taking scads of pictures, and one of its targets has been the stretch of space inside Mercury's orbit where small, faint vulcanoids could be hiding.

The concept of vulcanoids arose from research done in the late 1800s, when astronomers trying to use the classical rules of celestial mechanics to chart Mercury's orbit kept finding things wrong with their calculations.

French mathematician Urbain Jean Joseph le Verrier took the challenge to heart, and in 1860 he announced that discrepancies in Mercury's orbit were due to an unseen planet, which he named Vulcan.

Le Verrier's theory was eventually disproven thanks to Einstein's revolutionary theory of relativity—when you include the sun's gravitational field in the mix, Mercury's orbit works out just fine, thanks, no extra planet required.

But the concept of something being between Mercury and the sun has lived long and prospered, and a number of missions (some using fighter jets!) have kept the search alive over the years.

MESSENGER has been making its vulcanoid searches when its orbit brings it closest to the sun. The craft has taken a host of snapshots in June 2008, February 2009, and most recently in January 2010. So far, nada.

But on January 16 MESSENGER did get an eyeful of neighboring Venus, the brightest dot in this polka dotted field of view.

Of course, Venus is so wildly overexposed in this picture that it looks like someone shot a hole in the sky.

But that highlights just how hard MESSENGER has to stare to even hope to catch a glimpse of a vulcanoid—if any are out there at all.

Year's Biggest Full Moon, Mars Create Sky Show

The biggest full moon of 2010 will rise in the east Friday night, and it'll appear with a bright sidekick: Mars will cozy up just to the left of the supersize moon.

January's full moon is also called the wolf moon, according to Native American tradition associating this month's full moon with wolves howling in the cold midwinter. (Take a moon myths and mysteries quiz.)

The 2010 wolf moon will appear 30 percent brighter and 14 percent larger than any other full moon this year, because our cosmic neighbor will actually be closer to Earth than usual.

The moon will be at its closest perigee—the nearest it gets to our planet during its egg-shaped orbit—for 2010 at 4:04 a.m. ET Saturday, reaching a distance of 221,577 miles (356,593 kilometers) from Earth.

At its farthest from Earth, the moon is said to be at apogee. Perigee and apogee each happen generally once a month, but the moon's wobbly orbit means that the satellite's exact distance at each of those events varies over the year. The moon's phase can also be different during each apogee and perigee.

"This month has the largest full moon of 2010, because it coincides with the special moment when the full moon happens to occur on the same day as it is at perigee," said Marc Jobin, an astronomer at the Montréal Planetarium.

And in a remarkable coincidence, Mars is at opposition Friday—directly opposite to the sun in the sky—so that as the sun sets in the southwest, Mars rises in the northeast.

Around opposition, the red planet gets closest to Earth. This year Mars swung by at just 61 million miles (98 million kilometers) on January 27, and it will still appear remarkably bright during the weekend sky show.

"To the naked eye it will appear as a bright, orange-colored star right next to the full moon—the pair will jump out at you for sure," Jobin said.

Because this unusually close perigee is happening during a full moon, it is expected to have an effect on Earth's tides.

These effects should be modest, most likely measurable in inches, although perigee tides can be higher if there happens to be a storm surge at the same time.

As for observing the effects of perigee on the moon itself, most casual observers should notice an obvious difference in the moon's apparent size as it rises above the eastern horizon, Jobin said.

That's when an optical illusion usually comes into play that makes any full moon seem larger, since the moon is set against familiar Earthly objects rather than appearing high in the empty sky.

"The combination of the two effects—perigee and moon illusion—will be really be noticeable and spectacular near the horizon," Jobin said.

Strange "Comet" May Be Asteroid Collision Debris

A curious, comet-like object recently found in pictures from a ground-based telescope might actually be fallout from a high-speed asteroid collision, planetary scientists report.

If these suspicions are confirmed, the object would represent the first time astronomers have witnessed the immediate aftermath of such a cosmic smashup.

Dubbed P/2010 A2 (LINEAR), the fuzzy, tailed mystery object is about 130,000 miles (210,000 kilometers) to 190,000 miles (305,000 kilometers) long, stretching across part of our solar system's main asteroid belt.

The belt contains thousands of asteroids that orbit between Mars and Jupiter, some 250 million miles (402 million kilometers) from Earth.

It's believed most comets come from the cold, distant reaches of the solar system and travel on long, elliptical orbits, which keep the icy bodies far from the sun most of the time.

As a comet nears the sun, heat turns the comet's volatile ices into gases, and solar radiation pushes on those gases to create a tail.

But the newfound object suddenly appeared within the warmer asteroid belt and may even have originated there, puzzling astronomers.

"We're still trying to really figure out what it is," said University of Arizona planetary scientist Jim Scotti, who is part of one of the teams observing the object from the Kitt Peak National Observatory outside Tucson.

The object's oddities have some astronomers, including Scotti, thinking that the bright "tail" is actually a debris field created just after a small asteroid had smashed into a larger one. (See pictures of comets and asteroids.)

A 650-foot-wide (200-meter-wide) space rock apparently still sitting near the object's head could be one of the collision victims.

Odds are that the smaller impactor would have been only a few meters across, since asteroids of this size are far more common in the main belt.

If a collision occured, it's most likely that the space rocks didn't meet head on, Scotti said. Still, the impact speed could have ranged from 0.6 to 6 miles (1 to 10 kilometers) a second—fast enough to create a debris field visible from Earth.

Astronomers have yet to witness an actual asteroid collision. But there's plenty of evidence to suggest that the smashups happen all the time.

For instance, all known asteroids display telltale scars in the forms of impact craters. And some groups of asteroids are thought to have been born from collisions that fragmented their original "parents."

"With such evidence of collisions in the asteroid belt, it's not surprising that eventually we will see one," Scotti said.

The trick is, "I'm not sure we know what an asteroid collision really would look like in detail," he admitted.

"We have some ideas, but I'm not sure anyone has really sat down and modeled the size and velocity of the debris, or where all that debris goes and how long it would remain potentially observable."

For now, scientists can only wait and watch to see if P/2010 A2 (LINEAR) slowly dissipates, like debris from an explosion, or continues to act like a comet—which would pose a new round of puzzling questions.

A rare handful of comet-like bodies are known to orbit in the main asteroid belt. But if P/2010 A2 (LINEAR) is actually a comet, how did it conserve its water ice so close to the sun for some 4.5 billion years—roughly the age of the solar system—only to begin releasing gases now due to some unseen event?

"That's a long time to bake an object," Scotti said.

"It's hard to imagine how an object would maintain a reservoir of volatiles that it could use to suddenly start producing a tail. But you know, stranger things have happened."

Yearlong Star Eclipse May Help Solve Space Mystery

While relatively few people were looking, an unusual eclipse darkened New Year's Day.

On January 1 a giant space object blotted out our view of Epsilon Aurigae, a yellow supergiant star about 2,000 light-years from Earth. Based on studies of Epsilon Aurigae's previous eclipses, astronomers expect the star won't fully regain its bright shine until early 2011.

Normally the star is so bright it can be seen with the naked eye even by city dwellers. For all but the most rural star-gazers, though, the mystery object that eclipses the star causes it to vanish for about 18 months every 27.1 years.

Ever since the star's periodic eclipses were first recorded in 1821, astronomers have been puzzling over how Epsilon Aurigae pulls off its lengthy disappearing act.

Now, "using data from the Spitzer Space Telescope, we've reached a solution to a nearly two-century-old mystery," study leader Don Hoard, of the California Institute of Technology, said today at an American Astronomical Association press briefing in Washington, D.C.

According to the new model, Epsilon Aurigae is a dying star being orbited by another star, and that stellar dance partner is cloaked in a wide disk of dark dust.

Based on the new Spitzer data, Hoard's team thinks the eclipse lasts so long because the dark disk is about 744,000,000 miles (1,197,351,936 kilometers) across—eight times as wide as the distance from Earth to the sun.


Binary star systems have long been known to cause stellar eclipses as seen from Earth. Epsilon Aurigae is unusual, though, because it has the longest lasting known eclipse.

The 18-month eclipse started last August, but it took the disk until now to fully obscure Epsilon Aurigae.

"If the eclipse was simply being caused by another [darker] star passing in front of the visible star, it shouldn't last that long," Hoard said.

Astronomers had suggested in the 1950s that whatever is passing in front of Epsilon Aurigae is masked by a disk of material.

The new Spitzer data, combined with readings of other light waves from ground and space-based observatories, suggest that the star inside the disk is a B-type, a blue star three times as hot as our sun.

At first, the team wasn't sure how to explain the readings.

Assuming Epsilon Aurigae is as massive as other similar stars, a lone B star, Hoard said, shouldn't be massive enough to generate enough gravity for the binary pair to orbit they way they do.

"So then we started thinking, Well, we need more mass but no more light" in the system for the disk model to work, he said.

The team started by wondering whether something else might join the B star at the center of the disk.

A black hole would add the mass the scientists thought was needed, but it would also add more light than has been observed in the system. That's because a black hole would gobble up matter from the disk, then spit it out in the form of detectable radiation.


Perhaps, though, the object in the disk wasn't the problem at all, the astronomers thought, but rather Epsilon Aurigae itself.

"So we back up for a minute and say, OK, what if [Epsilon Aurigae] is not a massive supergiant star? What if it's a low-mass … dying star?" Hoard said.

Such a star "can be big, but it doesn't have to have a lot of mass," Hoard said.

"And if we start with that assumption, everything just falls nicely into place."

In other words, the model of a large but low-mass star orbited by a B star shrouded in dust matches the centuries of data collected so far on Epsilon Aurigae—potentially explaining once and for all how the long, strange eclipse is possible.


Other experts, however, are not quite ready to close the case file.

"Don says that we've solved it. I disagree," said Arne Henden, director of the nonprofit American Association of Variable Star Observers.

Even with the new model, he argued, the Epsilon Aurigae system is full of mysteries, such as the structure and composition of the supposed dark disk.

"What is the nature of this dusty disk? These are things you normally see around young stellar objects," said Henden, who is also a senior research scientist for the Universities Space Research Association at the U.S. Naval Observatory in Flagstaff, Arizona.

But the blue star in the new model would be much older, and its dusty disk seems to be filled with unusually large particles.

"There are still a lot of details that need to be worked out," study leader Hoard agreed. 

Both astronomers hope that during the current Epsilon Aurigae eclipse, modern technology combined with extensive public participation will help answer the lingering riddles.

Henden's star-observer organization is helping to organize a project called Citizen Sky, in which backyard astronomers are being trained to monitor Epsilon Aurigae's eclipse from start to finish.

Since the project's launch last September, more than 120 people in 19 countries have already submitted data.

"Technology has evolved tremendously since the last eclipse [in 1984], and amateur astronomers are able to get exquisite detail on a nightly basis," Henden said.

Aside from engaging the public in astronomy, he added, the Citizen Sky project "shows that classical astronomy"—using earthbound, optical telescopes—"is still alive and well."

Our Solar System May Have Millions of "Twins"

Of the billions of stars in our Milky Way galaxy, 15 percent may host "twins" of our solar system, a new study says.

While that might not sound like much, the find suggests that several hundred million star systems look a lot like the one we call home, the study authors say.

The research is based on surveys of stars with gas giant planets—similar toJupiter and Saturn—that orbit far from their stars.

As in our solar system, vast distances stretch between these stars and their gas giants. This creates ample room for rocky planets to thrive in the stars' habitable zones, the regions where liquid water can exist.

And that boosts the likelihood that other Earths, and maybe even other forms of life, abound in the Milky Way.

"For the first ten years of planet hunting, we were feeling a bit worried—other systems looked so different from our own solar system," noted Debra Fischer, an astronomer at San Francisco State University who was not involved in the research.

"[These] results are reassuring us that there are solar systems akin to our own. This is real data that strengthens the hypothesis that there are many habitable worlds like our Earth."



Astronomers think that gas giants generally form farther from their stars, while rocky worlds like Earth form closer in.

But in some star systems it's thought that gas giants migrate inward, knocking any smaller planets out of their orbits or destroying the rocky worlds outright.

Meanwhile, star systems like ours have gas giants in stable outer orbits.

"In these systems there is room for terrestrial planets to prosper and not get knocked out of their orbits," said study co-author Andy Gould, an astronomer at Ohio State University. 

What's more, studies of Jupiter suggest that outer gas giants can act as gravitational shields, protecting inner rocky worlds—and any life-forms on them—from frequent asteroid impacts.

To find such star systems, nearly a hundred scientists joined forces as part of the Microlensing Follow-Up Network, or MicroFUN, to scour the galaxy using a technique called gravitational microlensing.

In this method, when one star passes in front of another, as seen from Earth, the nearer star's gravity acts like a lens, bending and magnifying the more distant star's light.

If the nearer star has orbiting planets, keen-eyed observers can spot the subtle clues of their presence in the magnified light.

If all the stars in the Milky Way hosted solar system twins, astronomers should have found at least six such systems them by now, according to a statistical analysis of four years' worth of microlensing data.

But so far, only one other system like ours has been spotted: In 2006 astronomers found a star with its own versions of Jupiter and Saturn.

That means just 15 percent of the galaxy's stars must have solar systems like ours, Gould and colleagues announced this week at the 215th meeting of theAmerican Astronomical Society in Washington, D.C.


Gould cautioned that his team's "very rough" estimate is based on limited data and is likely to change as other star systems are spotted in the coming years.

For instance, some systems could house only Earthlike planets and no gas giants, Gould said. But for now we don't know, since most stars are too far away for current instruments to detect small, rocky worlds.

That might change as newer planet-hunting missions, such as the Kepler space telescope, begin to bear fruit.

Still, the new findings are in line with recent studies that say lower-mass planets such as "super Earths" might be relatively common in the galaxy, said Michael Meyer, of the Institute for Astronomy in Zurich, Switzerland.

"It may turn out that stars harboring even lower-mass terrestrial planets may be the rule rather than the exception," said Meyer, who was not involved in the study.

"If so, understanding the dynamical relationship between the smaller terrestrial planets and the more massive gas and ice giants may help us to understand how common Earthlike planets might be in our galaxy."

Nearby "Super Earth" May Have Oceans, Thick Atmosphere

A newfound "water world" orbiting a star just 40 light-years away is the first known Earthlike planet close enough for us to "sniff" its atmosphere, astronomers say.

Dubbed GJ 1214b, the planet is only about 2.7 times larger than Earth and about 6.5 times more massive.

Based on its density, scientists think GJ 1214b is made up of about three-quarters liquid water with a solid core of iron and nickel and an atmosphere of hydrogen and helium—not unlike Earth.

But in most other ways, the planet is a "very different beast" from our home world, the researchers say.

"It's basically one big ocean," said study leader David Charbonneau of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.

"There are no continents of rock floating on top or peaking up through the water."

Moreover, GJ 1214b is hotter than Earth and its atmosphere is ten times thicker than our own, the study authors say.

This would make things difficult for life as we know it. For starters, the atmospheric pressure on the planet's surface must be immense, and very little light would be able to penetrate the haze to reach the oceans.

The new super-Earth was discovered using the MEarth project, a suite of small, ground-based telescopes set to detect minute changes in the brightness of dim, red stars known as M dwarfs.

Periodic dips in starlight can be caused by planets that partially eclipse, or transit, their host stars. Because M dwarfs are dimmer than stars like our sun, it's easier to spot light reductions caused by smaller Earth-size planets.

Although GJ 1214b isn't directly visible, the exact changes in starlight due to its transit allowed astronomers to measure the planet's size and mass, offering clues to its composition.

And because the water world is so close to Earth, Charbonneau added, space-based optical telescopes such as Hubble or Kepler could one day be used to "sniff out" the exact chemicals in the planet's atmosphere.

"Some of the light from the star passes through the atmosphere [on its way to Earth], and imprinted on that are features of whatever atoms and molecules are present," Charbonneau said.

Overall, the discovery is a "landmark find" that fills a knowledge gap in planetary science, said Greg Laughlin, an astrophysicist at the University of California, Santa Cruz, who was not involved in the study.

"I've always wondered what a six-Earth-mass planet would be like," Laughlin said. "Now we know. It's something completely alien to our own solar system."

Five New Planets Found; Hotter Than Molten Lava

Five new planets have been found orbiting distant stars—the first confirmed new worlds from NASA's recently launched Kepler space telescope mission, astronomers announced today.

Like many of the more than 400 exoplanets—planets outside our solar system—found to date, the new planets are so-called hot Jupiters. They're about the same mass as Jupiter and orbit very close to their host stars, which makes the planets relatively easy to spot from Earth.

The smallest of the new planets is about the same size as Neptune, though much more massive. All of the planets are hotter than molten lava and could turn gold to goo, according to NASA temperature estimates.

Dubbed Kepler 4b, 5b, 6b, 7b, and 8b, the five new planets range in temperature from 2,000 to 3,000 degrees Fahrenheit (1,090 to 1,650 degrees Celsius), William Borucki, Kepler's principal investigator, said today during a press briefing at the American Astronomical Society's annual meeting in Washington, D.C.

One of the worlds, Kepler 7b, is among the lowest-density planets yet found, with about the same density as Styrofoam, he said.

These planets are "certainly no place to look for life—that will be coming later," with discoveries of Earth-like planets, Borucki said.

Kepler's main goal is to find rocky, Earthlike planets orbiting in stars' habitable zones—the regions in which planets receive enough heat from their stars for liquid water to exist.

While the new finds don't meet those criteria, they do show that the instrument is working as expected—offering "a tantalizing hint at what we can expect in a few years' time," noted Greg Laughlin, an astronomer at the University of California, Santa Cruz.

"It's wonderful to see Kepler working so well."

epler looks for extrasolar planets by spying the decrease in starlight as a planet transits, or crosses in front of, its host star, as seen from Earth.

The orbiting telescope, which launched last March, spotted the five new worlds in its first six weeks of operation.

Each planet's existence was later confirmed using a method called radial velocity, which looks for the wobble in a star's orbit caused by the gravitational pull of an orbiting planet.

The radial velocity observations were "a beautiful match" for Kepler's data, Borucki said. "It completely confirms that we really have planets here."

Having both sets of data creates a "truly valuable situation" in planet hunting, UCSC's Laughlin added.

That's because each method does more than just help confirm the other. Each technique provides different types of information, which help build a more complete picture of the alien world.

Radial velocity, for example, gives details about a planet's mass and orbit, while transits can reveal a planet's size relative to its star. This in turn tells astronomers about the planet's density.

Planet-hunting missions such as Kepler have shown us that the densities of exoplanets are all over the map, Laughlin said.

Some of the biggest worlds, for instance, have been found to be unexpectedly "puffed up" by an as-yet unexplained heat source.

Kelper 5b, for instance, is much more massive than Jupiter but is much less dense then water, said mission co-investigator Dimitar Sasselov.

"It's like looking at a football team," Laughlin said. "You might guess that they're all 250 to 300 pounds. But then you find out that some of them are 25 pounds—that would come as a surprise."

Although Kepler's five new planets are the only ones confirmed by the mission so far, the telescope's first few months of data actually contain hundreds of candidates.

The Kepler mission, expected to last at least three and a half years, will likely announce many more new worlds in coming years as astronomers are able to confirm the planets' existence.

But it will take several Earth years before Kepler scientists can be sure they've seen an Earth-size world in its star's habitable zone, Laughlin said.

That's because a planet orbiting at the right distance from its star will be farther out than a hot Jupiter and so will take much longer to complete an orbit of its star—making transits much rarer.

To be sure you've seen a planet, "you have to watch long enough to see three to four transits," Laughlin said.

Overall, though, the new finds help make it clear that planets with otherwise similar traits can have very different personalities, Laughlin noted.

"It's not a situation of, You've seen one, you've seen them all."

Cosmic Conundrum Hits Close to Home

By the time cosmic rays hit Earth, they have journeyed through so many magnetic fields and other perturbations that they arrive nearly uniformly from all directions.
So when a detector in New Mexico began registering streams of charged particles coming from the general direction of the Orion nebula and about 500 light-years from Earth -- a neighbor by astronomical measures -- scientists took note.
"I can't tell you what it is, but I can tell you what it isn't," said University of Maryland physicist Jordan Goodman, "It isn't a statistical fluctuation in our data. It's not an error."
Scientists aren't sure what causes cosmic rays, which are charged particles, namely protons and electrons, moving at high speeds due to unknown events. The list of candidates includes supernova explosions and quasars.A local source of cosmic rays is one explanation for the finding made by Goodman and his colleagues, though what that could be is pure conjecture.
Another theory is that the rays originate from afar, but are being funneled toward Earth due to a magnetic field from an object such as Geminga, a relatively young pulsating star that is surrounded by clouds of molecular gas. Geminga radiates brilliantly in high-energy gamma rays.
"If Geminga is the source, it isn't clear that we would see it," Goodman said. "The magnetic fields would have to be aligned in some way" relative to Earth.
The finding was the second in less than a month that uncovered unusual evidence of cosmic rays.
Scientists using a detector on a balloon-borne experiment above Antarctica found more cosmic ray electrons than expected and suggested dark matter may be responsible, since the energy signals match what physicists believe would result when dark matter is annihilated."It is certainly possible that known astrophysical objects, such as nearby supernova remnants, spinning pulsars or, possibly, microquasars are responsible," said Yousaf Butt, with the Harvard-Smithsonian Center for Astrophysics.
Goodman and his colleagues made their discovery with the Milagro Gamma Ray Observatory, which is located in a covered pond, about the size of a football field, in the Jemez Mountains near Los Alamos, N.M.
The observatory detects highly energized particles striking the atmosphere by measuring the cascading effects on secondary particles that make it to the planet's surface.
Since the study began more than seven years ago, Milagro -- Spanish for "miracle" -- has detected more than 300 billion hits. Goodman's work was published last month in Physical Review Letters.

Space Wakeup Songs

Space shuttle crews in orbit probably don't need a prod from Mission Control to get going in the morning, but the wake-up song has become a NASA tradition.
Astronauts' families and friends often make suggestions for tunes and occasionally provide the music. Sometimes the wake-up song is very personal, such as the serenade of teacher-astronaut Barbara Morgan by her singer-songwriter son Adam. Often, it's the mission itself that provides the inspiration.
Here's a look at Discovery Space's favorites:
10. Mission: Impossible
Not taking any chances, Mission Control waited until the Hubble Space Telescope servicing crew of 2002 had completed most of its work before piping in the "Mission: Impossible" theme song to get things moving on flight day eight.
Recording: WAV - Net Show - RealAudio
9. Rocky
It was a moment of triumph when Kathryn Sullivan floated outside the airlock of space shuttle Challenger in October 1984 to become the first American woman to walk in space. Her crewmates included Sally Ride, NASA's first female astronaut. NASA marked the mission by playing the theme song from "Rocky."
8. Free Bird
Two Russians joined the crew of space shuttle Atlantis in September 2000 to get the newborn International Space Station ready for its first long-duration residents. After 10 days at the outpost, the astronauts were ready to come home. Wakeup music the day they departed -- Lynyrd Skynyrd's "Free Bird."
Recording: WAV - Net Show - RealAudio
7. Godzilla Vs. Space Godzilla
NASA wasn't anticipating any trouble when it woke the crew of shuttle Endeavour with the battle scene song from the movie "Godzilla Vs. Space Godzilla," then followed up with few bars of Blue Oyster Cult's "Godzilla." Astronaut Al Drew wrapped up by wishing Japanese astronaut Takao Doi good morning -- in Japanese.
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6. Pigs in Space
Joe Engle and Richard Truly had to end the second mission of the space shuttle program three days early when a generator failed. But the men worked through the night to complete a series of tests on the shuttle's new robot arm. They enjoyed a bit of comic relief with skits from The Muppets' "Pigs in Space."5. Attack of the Killer Tomatoes
NASA's Long Duration Exposure Facility (LDEF) was supposed to spend a year in orbit for tests of how various materials weathered the harsh space environment. But because of the Challenger accident, five years passed before LDEF came back to Earth. NASA didn't know what to expect from the experiments, which included 12.5 million tomato seeds. With tongue in check, Mission Control roused the LDEF retrieval crew with "Attack of the Killer Tomatoes."
4. Do You Want to Know a Secret?
After shuttle Atlantis lifted off in December 1988, NASA imposed a news blackout to keep details of its Department of Defense mission classified. Word leaked out about a special wake-up recording produced by a Houston radio station. With background music from the "Star Wars" theme song, the voice of Darth Vader greeted the crew. Satirical lyrics from The Beatles' "Do You Want to Know a Secret?" followed. Pentagon officials were not amused.
3. Monster Mash
Flight controllers opted for a bit of Halloween humor when it woke the crew of STS-58 with "Monster Mash," by Bobby "Boris" Pickett. Instead of goblins and bats, the shuttle had rats -- 48 of them (all caged, of course) -- for a series of life science experiments.
2. Woody Woodpecker
NASA delayed launching the STS-70 mission after discovering woodpeckers had drilled holes in insulation covering the space shuttle's fuel tank. During repairs, Woody Woodpecker was added to the crew patch as an ex-officio member of the crew. The first wakeup song of the mission was a homage to Woody, of course: the theme from Woody Woodpecker TV show.
1. We've Only Just Begun
The Apollo 17 astronauts left the moon in 1972 not knowing if or when people would be back. Among their wake-up tunes: The Carpenters' "We've Only Just Begun."

16 Days in Space and ??? To Get Home

Ten days after a detoured landing in California, the space shuttle Endeavour has begun a cross-country piggyback ride on top of a modified jumbo jet enroute to Florida.It’s not an easy journey. The 100-ton spaceship makes for one burly passenger, vulnerable to high winds, rain and other rather typical atmospheric phenomena, particularly during winter. It took two days just for the weather to be good enough to begin the journey.

The shuttle and its entourage made it as far as Fort Worth, Texas, last night. NASA says the chance the ferry flight would arrive at the Kennedy Space Center in Florida today are pretty slim, given an advancing cold front.

NASA is not as eager to talk about why the shuttle landed in California in the first place. Typically, flight directors will keep the orbiter in space an extra day if conditions in Florida preclude a touchdown on the scheduled landing day. Florida weather is notoriously fickle, sometimes difficult to predict an hour in advance, let alone a day.

So NASA’s call to divert Endeavour to California raised a few eyebrows, at least in Florida. It’s not really the money, though the $1.8 million it costs for the relocation would cover more than a few scholarships and salaries. It’s more about the time it takes to make the flight and the risks to the ship during the journey.

“It kind of struck us as a little unusual,” said George Diller, whose days as a NASA public affairs officer date back longer than my 21 years as a reporter covering the program. “Usually they wait at least one day before they make a call to come down there.”

“They” is the good folks at the Johnson Space Center in Houston, who runs the show from the time the shuttle clears the top of the launch tower to wheels stop on the runway.

I got curious about how the weather actually turned out on Dec. 1, the day the shuttle likely would have landed if a 24-hour delay had been ordered.

Apparently, I wasn’t the only one, because Bill Johnson, the news chief at KSC, had the report on the ready: North to northwest winds up to 10 knots. Visibility: Unlimited. In other words, a good day for landing.

The response from JSC was not so warm. “Wow, you’re the weather forecaster now,” sneered one public affairs officer whom I’ll not name on the condition that he promise to refrain from using sarcasm in the future when responding to uncomfortable questions like, “Why didn’t NASA wait a day to see if the weather in Florida got better?”

He also told me predictions from the Spaceflight Meteorology Group were that crosswinds at the Florida runway were “on the edge” (the limit is 15 knots.)

KSC folks weren’t buying that. “All you had to do was watch any local TV station and they were all predicting it was going to be a nice day,” said another press officer whom I’ll not name because I like him and I don’t want him to get in trouble for speaking his mind to a reporter.

Bottom line appears to be that NASA could have landed in Florida on Dec. 1. Now, that’s not to say that there wasn’t some OTHER more compelling reason to bring Endeavour back to Earth on the first best opportunity, such as maybe those fine folks flying in space were ready to get home.

That’s OK by me and I’ll happily fork over my share of the $1.8 million ferry flight tab. Heck, this is the agency that sent astronauts to the moon, for god’s sake. Surely, they know best about when -- and how best -- to bring our spacebirds home. I’m just one of those people who like to know what I’m paying for.

ASTRONOMERS ZERO IN ON MILKY WAY'S BLACK HOLE

Canada — German astronomers monitoring the motions of 28 stars at the center of the Milky Way galaxy have reported a new, more precise value for the mass of the supermassive black hole believed to lurk there.

The black hole weighs the equivalent of 4.31 million suns, with an uncertainty of plus or minus 0.36 million, Reinhard Genzel of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, reported in Vancouver December 10 at the Texas Symposium on Relativistic Astrophysics. The observations also pinpoint the distance from the Earth to the galaxy’s center at 27,000 light-years.

The findings will appear in an upcoming Astrophysical Journal and currently appear online at http://arxiv.org/abs/0810.4674.

During his talk, Genzel proclaimed that the new mass and its precision are evidence for the supermassive black hole’s existence, evidence that extends “beyond any reasonable doubt.”

But Andrea Ghez of the University of California, Los Angeles, who leads a rival team studying the galaxy’s center, notes that for years both groups have reported precise enough numbers to offer compelling evidence that the galaxy's center is a black hole.

The orbits of stars whipping about the core indicate such a mass, and also suggest that this immense concentration of matter must fit into such a small volume that it would quickly crunch down into a black hole.

Now, says Ghez, sharper optics and more observations present both teams with new obstacles in making more precise measurements. Ironically, with the current estimates for the mass of the central black hole, “we have more maturity in our answer, but less certainty.” Before, she says, “we were acting like teenagers, being very emphatic with very little information.”

Ghez and her colleagues describe some of the new challenges in the December 20 Astrophysical Journal.

Among the issues, she says, are concerns about distinguishing radiation emitted by stars from light emitted by matter falling onto the putative black hole. Confusing the two radiation sources could throw off calculations of a star’s orbit, which would make the calculated mass of a black hole more uncertain.

Another problem, cited by both Ghez and Genzel, is the lack of a good reference frame at the galaxy’s center. From year to year, as the researchers more carefully track the orbits of stars at the core, it’s unclear how to gauge stellar motion when all the stars in the image are moving and there’s no fixed frame of reference. “It’s like taking images while on a merry-go-round,” says Ghez. Such details didn’t matter as much when observations were not as sharp, she adds.

Jupiter Moon Has Violent, Hidden Oceans, Study Suggests

Locked under ice, the hidden oceans of Europa, one of Jupiter's moons, may be tumultuous rather than placid, a new study says.

Such oceanic unrest translates into a higher potential for life.
Robert Tyler, an oceanographer from the University of Washington, has used computer simulations to show that Jupiter's effects on its moon Europa may work differently than scientists once thought.

Rather than just stressing the moon's solid parts—squeezing its rocks and flexing a global shell of ice—Jupiter's relentless tugging may also generate huge planetary waves in Europa's submerged ocean.

These waves could be the primary vehicles for distributing energy, as heat, across Europa. The new theory counters a widely held impression that Europa's ocean is calm.

"Suddenly, now our whole conception has to be one of very energetic oceans sloshing around under this ice," Tyler said.

"I consider the specific case of Europa, but the general results apply equally to other moons with suspected oceans," he wrote in his paper, which appears in the journal Nature this week. Those moons include Jupiter's Callisto and Ganymede, along with Saturn's Enceladus and Titan.

Heat seekers

Europa travels a slightly oblong orbit around Jupiter. When it reaches the sharper curves at either end, the moon wobbles to release pent-up energy, which translates into tides.
Tyler is the first to suggest that Europa, like Earth, may dissipate most of its tidal stresses in oceanic waves.

David Stevenson, a planetary geologist at the California Institute of Technology in Pasadena, called the new theory "an interesting possibility" in an email.

"But at the end of it all, what I see here is a possibility that could well be (and most likely is) less important than the conventional story," he wrote.

"It would of course be more exciting and relevant if we were at a loss to understand how dissipation takes place at all. But that's not the situation."

Stuff of Life

NASA's Galileo spacecraft investigated Jupiter and its moons between 1989 and 2003, and sent data indicating that Europa's ocean could be salt water.

"That doesn't necessarily mean sodium chloride [salt]," Tyler said. "It could be magnesium sulfate, basically an Epsom bath."

Jeff Kargel, a geologist affiliated with the University of Arizona in Tucson, suggested in the late 1990s that Europa's salts may help it host life.

Kargel pointed out that many unknowns remain with respect to the composition and thickness of the liquid on Europa and its overlying ice.

"The big thing is to have liquid water—and to the extent that this new paper adds an energy source—all the better for life's prospects."

Sky Show Friday: Biggest, Brightest Full Moon of 2008

Don't expect to spot an Apollo lunar lander. But Friday night, weather permitting, sky-watchers around the world will see the biggest and brightest full moon of 2008.

Although a full moon happens every month, the one that rises tomorrow will appear about 30 percent brighter and 14 percent larger than the other full moons seen so far this year.
That's because our cosmic neighbor will be much closer than usual. The moon will be at its closest perigee—the nearest it gets to Earth during its egg-shaped orbit around our planet.

At its farthest from Earth, the moon is said to be at apogee.
Perigee and apogee each happen generally once a month, but the moon's wobbly orbit means that its exact distance at each of those events varies over the year.

The moon's phase can also be different during each apogee and perigee.

"Typically we don't have the full moon phase and perigee coinciding at the same time, so that makes this event particularly special," said Ed Krupp, director of the Griffith Observatory in Los Angeles, California.

What's more, tomorrow's event will be the closest lunar perigee since 1993, at 221,560 miles (356,566 kilometers) from Earth.

The moon's farthest apogee for the year will occur a couple weeks later on December 26, when the natural satellite will be 252,650 miles (406,601 kilometers) from Earth.

Highest Tide

Because this unusually close perigee is happening during a full moon, it is expected to have an effect on Earth's tides.
"While high tides happen each month when the sun, Earth, and the moon are aligned, there is going to be an enhanced effect, with the moon being the closest it's been in more than a decade," said Ben Burress, staff astronomer at the Chabot Space and Science Center in Oakland, California
"This would result in extra-large tides in regions that are susceptible to them, like Nova Scotia's Bay of Fundy."
Features in the Bay of Fundy create a sloshing wave action that, in the bay's funneled and tapered basin, give rise to vast tidal ranges.
But even in such places, the effects of perigee are often modest, in most cases measurable in inches. But perigee tides can be higher if there happens to be a storm surge at the same time.

Observing the effects of perigee on the moon itself can be a bit trickier. Most casual observers may only notice a difference in the moon's brightness, Burress said.

The moon's apparent larger size might be most noticeable as it rises above the horizon at sunset.

That's when an optical illusion usually comes into play that makes the full moon seem larger—set against familiar Earthly objects—than when it's higher in the empty sky.

"This combination of the moon illusion and close perigee gives sky-watchers a chance to see the biggest and fullest moonrise possible," Burress said.

What makes this event particularly nice, the Griffith Observatory's Krupp added, is that everyone around the world can witness it without the need for special equipment, just clear skies.

"If you are charmed by the idea of seeing the biggest and brightest full moon visible in 15 years, be ready to go outside at sunset and watch for the rising moon in the east," he said.

"Or stay up all night and watch as the moon rides through the overhead skies—either way it will be a beautiful sight."

Sun's Cycles Can Forecast Floods, Drought?

The sun's fluctuations can help predict extreme climatic events on Earth decades ahead of time, new research suggests.

Solar cycles are 11-year phases during which the sun's activity ebbs and flows, accompanied by an increase in sunspots on the sun's surface.
The cycles, which are driven by the sun's magnetic turbulence, may influence weather systems on Earth, particularly the El Niño-Southern Oscillation, a periodic climatic system associated with floods and droughts mostly in the Southern Hemisphere.

"The sun is the engine of our climate," said lead study author Robert Baker, of the University of New England in Australia.

"It's like a vibrating string—its past vibrations can be used to predict future vibrations."

Those vibrations are the cyclical "twisting and untwisting" of magnetic fields that cause the sun's poles to flip at the start of each new cycle.
Climate and Sun Similarities

Longer magnetic cycles of about 90 years and 400 years are also found in astronomy records.

The Southern Oscillation Index, which measures the El Niño-Southern Oscillation system, seems to correspond with a 90-year sun cycle, Baker found.

For instance, the current index reading closely follows a trend observed in the 1920s.

Periods of greater solar disturbances are associated with rainy periods, whereas a calmer sun dovetailed with times of drought in Australia, Baker said.
The research appears in a recent edition of the journal Geographical Research.

Floods of the Future?
Data from the 1940s, coupled with astrophysicists' calculations of future solar cycles, could predict droughts and floods as far off as 2030, Baker said.

"We can look into the future based on the past to make predictions 10 to 20 years ahead."

El Niño and La Niña, which creates opposite climatic effects from El Niño, also affect North America.

That means long-range forecasting is possible for water availability in Mexico and the western United States, where droughts are often severe, Baker said.

How solar cycles may influence Earth's weather systems is not well understood, but Baker speculated that cosmic radiation is a factor.

For instance, Baker's research shows that periods of high cosmic radiation coincide with particularly long La Niñas, Baker said.

"This [area of research] is something that warrants further investigation," he said.

If the current index continues to mimic the 1920s cycle, then 2009 is set to be another cool year relative to the 1990s.

However, the next few years may be a little harder to predict, he added.

That's because the sun has already defied its typical 11-year cycle: The new round was supposed to begin in 2007, but only recently got underway.
Longer-term trends may also be influencing the timing of the new cycle, Baker said. The larger 400-year magnetic cycle, for instance, is expected to end in 2020.

Doubtful

However, other scientists have misgivings about the strength of the research and its value in predicting climate events.

Stuart Larsen, a climate ecologist at Monash University in Melbourne, Australia, believes that solar cycles may "play a role in driving climatic variation."

But he's doubtful of Baker's work, calling it "statistically flawed."

"No causal link between El Niño events and solar variability has been demonstrated, and I think it is very unlikely that any direct link exists," said Larsen, who was not involved in the research.

Julie Arblaster is a climatologist at the Bureau of Meteorology in Melbourne.

"While there may be some influence of the solar and magnetic cycles on the [Southern Oscillation Index] and Australian rainfall," Arblaster said, "the magnitude of the signal is quite small."