Super-Hot Plasma 'Rain' Falls on Sun in Amazing Video

Super-Hot Plasma 'Rain' Falls on Sun in Amazing Video - Loops of superheated plasma far larger than Earth rain down on the solar surface in a dazzling video captured by a NASA sun-watching spacecraft.

NASA's Solar Dynamics Observatory (SDO) watched as a medium-strength flare erupted from the sun on July 19, 2012. The blast also generated the enormous, shimmering plasma loops, which are an example of a phenomenon known as "coronal rain," agency officials said.

A huge loop of plasma "rain" falls on the sun in this screenshot from a video captured by NASA's Solar Dynamics Observatory spacecraft on July 19, 2012.

\A close-up of a spectacular loop of solar plasma "rain" on the sun as seen by NASA's Solar Dynamics Observatory spacecraft on July 19, 2012. NASA released a video of the amazing sight on Feb. 20, 2013.

"Hot plasma in the corona [the sun's outer atmosphere] cooled and condensed along strong magnetic fields in the region," NASA officials wrote in a description of the four-minute video of solar plasma "rain", which NASA released Wednesday (Feb. 20).

"Magnetic fields are invisible, but the charged plasma is forced to move along the lines, showing up brightly in the extreme ultraviolet wavelength of 304 Angstroms, and outlining the fields as it slowly falls back to the solar surface," they added.

The $850 million SDO spacecraft recently marked three years in space. It launched on Feb. 11, 2010, kicking off a five-year prime mission to provide incredibly detailed views of the sun, solar flares and other space weather events.

SDO has delivered thus far, capturing more than 100 million images of our star as of late last year. Some of the spacecraft's most memorable shots over the last year are highlighted in another video, which NASA released last week to celebrate the mission's birthday.

But SDO has done more than just shine a light on the sun. The spacecraft has also helped scientists better understand comets, especially "sungrazers" like Comet Lovejoy, which survived a death dive through the sun's corona in December 2011.

And scientists used SDO to learn more about Venus' atmosphere during the planet's "transit" across the sun's face, from Earth's perspective, in June of last year. The Venus transit transfixed skywatchers and researchers around the world, as the next one won't come until 2117.

SDO isn't the only spacecraft keeping tabs on the sun, which is currently in an active phase of its 11-year activity cycle, with a peak expected later this year. NASA's twin Stereo probes also provide daily views of our star, as does the Solar and Heliospheric Observatory, a collaboration between NASA and the European Space Agency. ( space.com )

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Weather Channel Explores Rogue Planet Doomsday Scenario

Weather Channel Explores Rogue Planet Doomsday Scenario - What if a rogue planet swept through the solar system, altering Earth's orbit? Potentially, the death of all life on the planet, according to a new Weather Channel special.

"Forecasting the End," a new Weather Channel series, premieres March 21, exploring the possible results of a rogue planet fly-by. Rogue planets, or planets not linked to stars, may outnumber actual stars in the Milky Way galaxy. Myths about "Planet X" or "Nibiru" hold that a stealth rogue planet is headed this way (actually, it was supposed to hit on the Mayan apocalypse on Dec. 21, 2012).

In fact, the likelihood of a rogue planet swinging by is slim. Astronomers have yet to find any evidence that any of the planets in our own solar system are captured rogues. And the average space between rogue planets and other bodies in our galaxy is quite expansive, Bad Astronomy blogger Phil Plait has calculated. In other words, a collision isn't likely.

The first episode of "Forecasting the End" focuses on what might happen in this very unlikely scenario. Potentially, scientists say, a planet passing by could alter the orbits of the planets in the solar system, making Earth's orbit more elliptical.

A more elliptical orbit would be bad news for life. Earth orbits in a relatively thin habitable zone around the sun, which allows for temperatures where water can be a solid, liquid or gas.

This more elliptical orbit might not push Earth out of this zone, but could bring the planet close enough to the sun to create short, extremely intense summers and then far enough away for very long winters. This would create a shorter growing period and mass food shortages, even human extinction.

"Life on Earth is very much dependent on the orbit we are in around the sun," said David Bennett, a University of Notre Dame astrophysicist.

To make the series, complete with simulations of the world-ending scenario, Weather Channel director Brea Tisdale and crew filmed real people "reacting" to disasters, which they added later using computer graphics. In one shot of a volcanic disaster, the crew sprinkled flour from above to look like ash.

"The actors have to pretend that something terrible is happening in the sky above them, when actually it's a really sunny, nice day," said director of photography Doug Cheney. ( LiveScience.com )

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NASA Sees Monster Sunspot Growing Fast, Solar Storms Possible

NASA Sees Monster Sunspot Growing Fast, Solar Storms Possible - A colossal sunspot on the surface of the sun is large enough to swallow six Earths whole, and could trigger solar flares this week, NASA scientists say.

The giant sunspot was captured on camera by NASA's Solar Dynamics Observatory as it swelled to enormous proportions over the 48 hours spanning Tuesday and Wednesday (Feb. 19 and 20). SDO is one of several spacecraft that constantly monitor the sun's space weather environment.

"It has grown to over six Earth diameters across, but its full extent is hard to judge since the spot lies on a sphere, not a flat disk," wrote NASA spokeswoman Karen Fox, of the agency's Goddard Space Flight Center in Greenbelt, Md., in an image description.

The sunspot region is actually a collection of dark blemishes on the surface of the sun that evolved rapidly over the last two days. Sunspots form from shifting magnetic fields at the sun's surface, and are actually cooler than their surrounding solar material.

According to Fox, some of the intense magnetic fields in the sunspot region are pointing in opposite directions, making it ripe for solar activity.

"This is a fairly unstable configuration that scientists know can lead to eruptions of radiation on the sun called solar flares," Fox explained.

The sun is currently in the midst of an active phase of its 11-year solar weather cycle and is expected to reach peak activity sometime this year. The current sun weather cycle is known as Solar Cycle 24.

NASA's Solar Dynamics Observatory launched in 2010 and is just one of a fleet of spacecraft keeping close watch on the sun for signs of solar flares, eruptions and other space weather events. ( SPACE.com )

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Flights rerouted as massive solar storm slams Earth

Flights rerouted as massive solar storm slams Earth - Solar radiation from a massive sun storm -- the largest in nearly a decade -- collided with the Earth's atmosphere on Tuesday, prompting an airline to reroute flights and skywatchers to seek out spectacular light displays.

US carrier Delta Air Lines said it had adjusted flight routes for transpolar journeys between Asia and the United States to avoid problems caused by the radiation storm, a spokesman said.

NASA confirmed the coronal mass ejection (CME) began colliding with Earth's magnetic field around 10:00 AM (1500 GMT) Tuesday, adding that the storm was now being considered the largest since October 2003.

Radiation storms are not harmful to humans, on Earth at least, according to the US space agency. They can, however, can affect satellite operations and short wave radio.

The storm's radiation, likely to continue bombarding Earth's atmosphere through Wednesday, and its possible disruption to satellite communications in the polar regions prompted the flight rerouting, airline officials said.

This January 23, 2012 image provided by NASA, captured by the Solar Dynamics Observatory, shows a solar flare erupting on the Sun's northeastern hemisphere at 03:49 UT. Solar radiation from a massive sun storm -- the largest in nearly a decade -- collided with the Earth's atmosphere on Tuesday, prompting an airline to reroute flights and skywatchers to seek out spectacular light displays. (AFP Photo/)

Atlanta-based Delta, the world's second largest airline, said "a handful" of routes had their journey adjusted "based on potential impact" of the solar storm on communications equipment, spokesman Anthony Black told AFP.

Routes from Hong Kong, Shanghai and Seoul took a more southerly route after the solar flare erupted on Sunday.

The airline said it would continue to monitor solar activity before return flights to their normal routes.

Due to the unusual intensity of the photons raining on Earth, the spectacular aurora borealis -- the stunning "Northern Lights" display -- which is often seen closer to the Arctic pole at this time of year, has been seen as far south as Scotland and northern England, and at lower latitudes in the United States.

The event started late Sunday with a moderate-sized solar flare that erupted right near the center of the Sun, said Doug Biesecker, a physicist with the National Oceanic and Atmospheric Administration Space Weather Prediction Center.

"The flare itself was nothing spectacular, but it sent off a very fast coronal mass ejection traveling four million miles per hour (6.4 million kilometers per hour)," he told AFP.

Space weather watchers said the best aurora sightings are normally around midnight local time.

Rob Stammes, who runs the Lofoten Polar Light Centre in Lofoten, Norway said the CME's arrival Tuesday had produced a surge in ground currents outside his laboratory. ( AFP )

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Solar storm sparks dazzling northern lights

Solar storm sparks dazzling northern lights — A storm from the broiling sun turned the chilly northernmost skies of Earth into an ever-changing and awe-provoking art show of northern lights on Tuesday.

Even experienced stargazers were stunned by the intensity of the aurora borealis that swept across the night sky in northern Scandinavia after the biggest solar flare in six years.

"It has been absolutely incredible," British astronomer John Mason cried from the deck of the MS Midnatsol, a cruise ship plying the fjord-fringed coast of northern Norway.

"I saw my first aurora 40 years ago, and this is one of the best," Mason told The Associated Press, his voice nearly drowning in the cheers of awe-struck fellow passengers.

U.S. space weather experts from the National Oceanic and Atmospheric Administration said Tuesday evening that so far they had heard of no problems from the storm that triggered the auroras, which made it as far south as Wales, where the weather often doesn't cooperate with good viewing.

It was part of the strongest solar storm in years, but the sun is likely to get even more active in the next few months and years, said physicist Doug Biesecker at the U.S. Space Weather Prediction Center in Boulder, Colorado.

"To me this was a wake up call. The sun is reminding us that solar max is approaching," Biesecker said. "A lot worse is in store for us. We hope that you guys are paying attention. I would say we passed with flying colors."

Even before particles from the solar storm reached the Earth on Tuesday, a different aurora Monday night was dancing across the sky as far south as Ireland and England, where people rarely get a chance to catch the stunning light show.

Those northern lights were likely just variations in normal background solar wind, not the solar storm that erupted Sunday, Biesecker said.

Tuesday's colorful display may not have moved that far south, limiting its audience, but those who got to see it got brilliance in the sky that had not been around for years.

"It was the biggest northern lights I've seen in the five-six years that I've worked here," said Andreas Hermansson, a tour guide at the Ice Hotel in the Swedish town of Jukkasjarvi, above the Arctic Circle.

He was leading a group of tourists on a bus tour in the area when a green glow that had lingered in the sky for much of the evening virtually exploded into a spectacle of colors around 10:15 p.m.

"We stopped the bus. And suddenly it was just this gigantic display of dancing lights and Technicolor," said Michele Cahill, an Irish psychologist, who was on the tour. "It was an absolutely awesome display. It went on for over an hour. Literally one would have to lie on the ground to capture it all."

But in -30 degrees F (-35 C), that didn't seem like a good idea.

An aurora appears when a magnetic solar wind slams into the Earth's magnetic field, exciting electrons of oxygen and nitrogen.

The northern lights are sometimes seen from northern Scotland, but they were also visible Monday night from northeast England and Ireland, where such sightings are a rarity.

"The lights appear as green and red mist. It's been mostly green the past few nights. I don't know if that's just special for Ireland," said Gerard O'Kane, a 41-year-old taxi driver and vice chairman of the Buncrana Camera Club in County Donegal in Ireland's northwest corner.

He and at least two dozen amateur photographers were meeting after dark at a local beach for an all-night stakeout. They've been shooting the horizon from dozens of locations since Friday night.

Scientists have been expecting solar eruptions to become more intense as the sun enters a more active phase of its 11-year cycle, with an expected peak in 2013.

But in recent years the sun appeared quieter than normal, leading scientists to speculate that it was going into an unusually quiet cycle that seems to happen once a century or so.

While the geomagnetic part of the solar eruption — which happened around 11 p.m. EST Sunday — was more of a fizzle, another earlier part of the sun's outburst was more powerful.

On Monday and Tuesday, the proton radiation from the eruption reached strong levels, the most powerful since October 2003. That mostly affects astronauts and satellites, but NASA said the crew on the International Space Station was not harmed and only a few minor problems with satellites were reported, Biesecker said.

However, some airplane flights over the North Pole have been rerouted because of expected communication problems from the radiation.

Geomagnetic storms cause awesome sights, but they can also bring trouble. According to the National Oceanic and Atmospheric Administration, problems can include current surges in power lines, and interference in the broadcast of radio, TV and telephone signals. No such problems were reported Tuesday.

Peter Richardson, a 49-year-old bar manager and part-time poet at the 17th-century Tan Hill Inn in northern England, said the pub — normally dead on a Monday night in January — was thronged until the wee hours of the morning with people who came to look at the lights.

"I just thought: 'Oh my God, this is just absolutely amazing,'" he said. "You do get a lot of spectacular skylines out here, but that was just something out of the ordinary. Very different."

Ken Kennedy, director of the Aurora section of the British Astronomical Association, said the northern lights may be visible for a few more days.

The Canadian Space Agency posted a geomagnetic storm warning Tuesday after residents were also treated to a spectacular show in the night sky.

John Manuel, a scientist with the Canadian Space Agency, said there's an increased chance of seeing northern lights over northern Canada on Tuesday night.

"It's not likely people in the major Canadian cities further south will see a significant aurora tonight," he said. "There's always a possibility but the current forecast is for a good show for people who live further north. It should be a particularly good night tonight." ( Associated Press )

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Strongest solar storm since 2005 hitting Earth

Strongest solar storm since 2005 hitting Earth — The sun is bombarding Earth with radiation from the biggest solar storm in more than six years with more to come from the fast-moving eruption.

The solar flare occurred at about 11 p.m. EST Sunday and will hit Earth with three different effects at three different times. The biggest issue is radiation, according to the National Oceanic and Atmospheric Administration's Space Weather Prediction Center in Colorado.

The radiation is mostly a concern for satellite disruptions and astronauts in space. It can cause communication problems for polar-traveling airplanes, said space weather center physicist Doug Biesecker.

This handout image provided by NASA, taken Sunday night, Jan. 22, 2012, shows a solar flare erupting on the Sun's northeastern hemisphere. Space weather officials say the strongest solar storm in more than six years is already bombarding Earth with radiation with more to come. The Space Weather Prediction Center in Colorado observed a flare Sunday night at 11 p.m. EST. Physicist Doug Biesecker said the biggest concern from the speedy eruption is the radiation, which arrived on Earth an hour later. It will likely continue through Wednesday. It's mostly an issue for astronauts' health and satellite disruptions. It can cause communication problems for airplanes that go over the poles. (AP Photo/NASA)

Radiation from Sunday's flare arrived at Earth an hour later and will likely continue through Wednesday. Levels are considered strong but other storms have been more severe. There are two higher levels of radiation on NOAA's storm scale — severe and extreme — Biesecker said. Still, this storm is the strongest for radiation since May 2005.

The radiation — in the form of protons — came flying out of the sun at 93 million miles per hour.

"The whole volume of space between here and Jupiter is just filled with protons and you just don't get rid of them like that," Biesecker said. That's why the effects will stick around for a couple days.

NASA's flight surgeons and solar experts examined the solar flare's expected effects and decided that the six astronauts on the International Space Station do not have to do anything to protect themselves from the radiation, spokesman Rob Navias said.

A solar eruption is followed by a one-two-three punch, said Antti Pulkkinen, a physicist at NASA's Goddard Space Flight Center in Maryland and Catholic University.

First comes electromagnetic radiation, followed by radiation in the form of protons.

Then, finally the coronal mass ejection — that's the plasma from the sun itself — hits. Usually that travels at about 1 or 2 million miles per hour, but this storm is particularly speedy and is shooting out at 4 million miles per hour, Biesecker said.

It's the plasma that causes much of the noticeable problems on Earth, such as electrical grid outages. In 1989, a solar storm caused a massive blackout in Quebec. It can also pull the northern lights further south.

But this coronal mass ejection seems likely to be only moderate, with a chance for becoming strong, Biesecker said. The worst of the storm is likely to go north of Earth.

And unlike last October, when a freak solar storm caused auroras to be seen as far south as Alabama, the northern lights aren't likely to dip too far south this time, Biesecker said. Parts of New England, upstate New York, northern Michigan, Montana and the Pacific Northwest could see an aurora but not until Tuesday evening, he said.

For the past several years the sun had been quiet, almost too quiet. Part of that was the normal calm part of the sun's 11-year cycle of activity. Last year, scientists started to speculate that the sun was going into an unusually quiet cycle that seems to happen maybe once a century or so.

Now that super-quiet cycle doesn't seem as likely, Biesecker said.

Scientists watching the sun with a new NASA satellite launched in 2010 — during the sun's quiet period — are excited.

"We haven't had anything like this for a number of years," Pulkkinen said. "It's kind of special." ( Associated Press )

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Scientists confirm rocks fell from Mars

Scientists confirm rocks fell from Mars — They came from Mars, not in peace, but in pieces - Scientists are confirming that 15 pounds of rock collected recently in Morocco fell to Earth from Mars during a meteorite shower last July.

This is only the fifth time in history that scientists have chemically confirmed Martian meteorites that people witnessed falling. The fireball was spotted in the sky six months ago, but the rocks were not discovered on the ground in North Africa until the end of December.

This is an important and unique opportunity for scientists trying to learn about Mars' potential for life. So far, no NASA or Russian spacecraft has returned bits of Mars, so the only samples scientists can examine are those that come here in meteorite showers.

Scientists and collectors are ecstatic, and already the rocks are fetching big bucks because they are among the rarest things on Earth, rarer even than gold. The biggest rock weighs more than 2 pounds(1 kilogram).

This handout photo provided by Darryl Pitt of the Macovich Collection shows an external view of a Martian meteorite recovered in December 2011 near Foumzgit, Morocco following a meteorite shower believed to have occurred in July 2011. Scientists are confirming a recent and rare invasion from Mars _ meteorite chunks that fell from the red planet over Morocco last summer. Meteorites from Mars are more than 1 million times rarer than gold. And this is only the fifth time experts have chemically confirmed fresh Martian rocks fell to Earth. The last time was in 1962. Scientists believe this meteorite fell last July because there were sightings of it. (AP Photo/Darryl Pitt, Macovich Collection)

"It's Christmas in January," said former NASA sciences chief Alan Stern, director of the Florida Space Institute at the University of Central Florida. "It's nice to have Mars sending samples to Earth, particularly when our pockets are too empty to go get them ourselves."

A special committee Tuesday of meteorite experts, including some NASA scientists, confirmed test results that showed the rocks came from Mars, based on their age and chemical signature.

Astronomers think millions of years ago something big smashed into Mars and sent rocks hurtling through the solar system. After a long journey through space, one of those rocks plunged through Earth's atmosphere, breaking into smaller pieces.

Most other Martian meteorite samples sat around on Earth for millions of years — or at the very least, decades — before they were discovered, which makes them tainted with Earth materials and life. These new rocks, while still probably contaminated because they have been on Earth for months, are purer.

The last time a Martian meteorite fell and was found fresh was in 1962. All the known Martian rocks on Earth add up to less than 240 pounds.

The new samples were scooped up by dealers from those who found them. Even before the official certification, scientists at NASA, museums and universities scrambled to buy or trade these meteorites.

"It's incredibly fresh. It's highly valuable for that reason," said Carl Agee, director of the Institute of Meteoritics and curator at the University of New Mexico. "This is a beauty. It's gorgeous."

Meteorite dealer Darryl Pitt said he is charging $11,000 to $22,500 an ounce and has sold most of his supply already. At that price, the Martian rock costs about 10 times as much as gold.

One important decision the scientists made Tuesday was officially to connect these rocks to the fiery plunge witnessed by people and captured on video last in mid 2011. The announcement and the naming of these meteorites, called Tissint, came from the International Society for Meteoritics and Planetary Science, which is the official group of 950 scientists that confirms and names meteorites.

Tony Irving of the University of Washington did the scientific analysis on the rocks and said there is no doubt they are from the red planet. Several of the world's top experts in meteorites told The Associated Press that they, too, are convinced.

Scientists can tell when meteorites are from Mars because they know what the Martian atmosphere is made of, thanks to numerous probes sent there. The chemical signature of the rocks and the Martian air match, Irving said.

Another clue is that because Mars is geologically active, its rocks tend to be much younger — millions of years old instead of hundreds of millions or more — than those from the moon or asteroids.

Most of the known Martian rocks on Earth have been around for centuries or longer and have been found in Antarctica or the desert. They look so similar to dark Earth rocks that if they fell in other places, such as Maryland, they would blend right in and never be discovered.

Because known Martian meteorite falls happen only once every 50 years or so — 1815 in France, 1865 in India, 1911 in Egypt and 1962 in Nigeria — this is a once-in-a-career or even a once-in-a-lifetime event.

Jeff Grossman, a NASA scientist who is the meteorite society's database editor, said there is a higher probability of finding "something interesting" from Mars on these rocks because they fell so recently. However, six months is a long time for Earthly contamination to occur, he said.

University of Alberta meteorite expert Chris Herd, who heads the committee that certified the discovery, said the first thing he would do with the rocks would be to rinse them with solvents to try to get rid of earthly contamination and see what carbon-based compounds are left.

But Cornell University astronomer Steve Squyres, who is the principal investigator for NASA's Mars Exploration Rover Program and the space agency's go-to guy on Mars, said unfortunately this type of rock is not the kind scientists are most hoping for. This find is igneous, or volcanic, rock.

A softer kind of rock that could hold water or life would be better, but that type is unlikely to survive a fiery re-entry through Earth's atmosphere, he said.

Scientists are hoping NASA and the European Space Agency will team up in 2018 to send robotic spaceships to Mars that can bring back samples of rock and dirt. Just this past weekend, a Russian probe that was going to try to bring samples back from a Martian moon came plummeting back to Earth in failure.

A Martian meteorite that was buried in Antarctica made news in 1996. NASA scientists theorized the rock showed traces of life from Mars. Even the White House declared it the first sign of life outside of Earth. Years of study since then have led much of the astronomy world to conclude there was insufficient evidence to support the claim. ( Associated Press )

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Is the Rocky Alien Planet Gliese 581d Really Habitable?

Is the Rocky Alien Planet Gliese 581d Really Habitable? - A rocky alien planet called Gliese 581d may be the first known world beyond Earth capable of supporting life as we know it, a new study suggests.

Astronomers performing a new atmospheric-modeling study have found that the planet likely lies in the "habitable zone" of its host star — that just-right range of distances that allow liquid water to exist. The alien world could be Earth-like in key ways, harboring oceans, clouds and rainfall, according to the research.

This conclusion is consistent with several other recent modeling studies. But it does not definitively establish that life-sustaining water flows across the planet's surface.

The new study assumes that Gliese 581d, which is about seven times as massive as Earth, has a thick, carbon-dioxide-based atmosphere. That's very possible on a planet so large, researchers said, but it's not a given.

The Gliese 581 system: Worlds of possibilities

Gliese 581d's parent star, known as Gliese 581, is a red dwarf located 20 light-years from Earth, just a stone's throw in the cosmic scheme of things. So far, astronomers have detected six planets orbiting the star, and Gliese 581d is not the only one intriguing to scientists thinking about the possibility of life beyond Earth.

Image released by European Southern Observatory - An image released by the European Southern Observatory (ESO) shows an artist's impression of the atmosphere around a super-Earth exoplanet, the name given to rocky exoplanets only a few times larger than our own. Gliese 581d, a rocky world orbiting a nearby star, has been confirmed as the first planet outside our solar system to meet key requirements for sustaining life, scientists say.

Another planet in the system, called Gliese 581g, is about three times as massive as Earth, and it's also most likely a rocky world. This planet received a lot of attention when its discovery was announced in September 2010, because it's located right in the middle of the habitable zone. That makes 581g a prime candidate for liquid water and life as we know it — if the planet exists.

Some researchers question the analysis used to discover the planet, and say they cannot confirm 581g in follow-up studies. The planet's discoverers, however, are standing by their find.

Gliese 581d orbits outside of 581g, far enough away from its star that researchers first thought it too cold for life when it was originally discovered in 2007. But a strong greenhouse effect may warm 581d up substantially, perhaps enough to support liquid water.

That's the tentative conclusion of the new study, as well as several other recent studies by different research teams that also modeled Gliese 581d's possible atmosphere.

Modeling an alien atmosphere

The planet Gliese 581d receives less than a third of the solar energy that Earth does from our sun, and it may be tidally locked (a situation in which one side of the world always faces its sun — a permanent day — and the other faces away, producing eternal night).

After Gliese 581d's discovery, it was generally believed that any atmosphere thick enough to keep the planet warm would become cold enough on the night side to freeze out entirely, ruining any prospects for a habitable climate, researchers said.

The research team tested that possibility in the new study, developing a new kind of computer model that simulates alien planets' atmospheres and surfaces in three dimensions. The model is similar to those used to study climate change on Earth.

When the team ran the model, they found that Gliese 581d probably can indeed host liquid water if it has a dense carbon dioxide atmosphere. Even though the planet is relatively far away from its dim red dwarf parent star, it could be warmed by a greenhouse effect, with daytime heat circulated around the planet by the atmosphere.

The team, led by scientists from the Laboratoire de Métrologie Dynamique (CNRS/UPMC/ENS/Ecole Polytechnique) at the Institut Pierre Simon Laplace in Paris, France, published their results in The Astrophysical Journal Letters.

The work remains speculative.

To determine conclusively if Gliese 581d is truly habitable, future work will probably have to detect and characterize its atmosphere directly. And that is likely years off, since it requires the development of new and advanced telescopes. Human-made probes won't be getting to the planet anytime soon; with current technology, it would take spacecraft hundreds of thousands of years to make the 20-light-year trek. ( Space.com )

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