Dunlap Institute for Astronomy and Astrophysics; Mediafarm

An artist's rendering shows the HR 8799 planetary system at an early stage in its evolution, with HR 8799c in the foreground. That giant planet orbits its parent star at a distance comparable to Pluto's distance from our sun.

Astronomers say they've confirmed the presence of water vapor and carbon monoxide in the atmosphere of a giant planet beyond our solar system, thanks to the most detailed spectroscopic scan ever made.

The observations, detailed Thursday on the journal Science's website, uses a method that could someday be used to sample the air of an alien Earth from light-years away, the researchers said.

"The big surprise was actually that we could do it," one of the study's co-authors, Travis Barman of the Lowell Observatory in Arizona, told reporters. "We can actually see the individual lines of these molecules. ... I personally felt like we would not be able to do what we have done."

This isn't the first time scientists have studied the atmosphere of HR 8799c, a planet about seven times as massive as Jupiter that orbits a star 130 light-years from Earth. The HR 8799 system is special because astronomers can actually pick up the light of several giant planets that orbit outside the glare of their parent star. HR 8799c, for example, follows an orbit similar to the one Pluto traces around our own sun.

That's what makes it possible for astronomers to get the "chemical fingerprint" of the planet's atmosphere. One team did it three years ago with an instrument on the European Southern Observatory's Very Large Telescope in Chile. Another team reported just this week that they did it for four planets in the HR 8799 system using an instrument known as Project 1640 on the Palomar Observatory's Hale Telescope in California.

Higher resolution
Barman and his colleagues said they used the OSIRIS spectrograph on the Keck II telescope in Hawaii to produce a chemical fingerprint with enough resolution to determine which chemicals were present in the atmosphere, and which were not.

They found that the planet had a cloudy atmosphere containing water vapor and carbon monoxide — but not methane, as some researchers had previously suspected. Methane is an ingredient in the atmospheres of our own solar system's giant planets.

RC-HIA / C. Marois / Keck Observatory

This is one of the discovery images of the HR 8799 planetary system, obtained by the Keck II telescope using the adaptive optics system and NIRC2 Near-Infrared Imager. The rectangle indicates the field-of view of the OSIRIS instrument, centered on HR 8799c.

HR 8799c isn't a likely candidate to harbor life as we know it. It's far too gassy and hot, with a surface temperature of 1,800 degrees Fahrenheit, or 1,000 degrees Celsius. But the same spectroscopic method could theoretically be used to analyze the atmospheres of Earthlike planets for signs of life — if the telescope could be made big enough.

"If you wanted to do an Earth-sized planet, you really need a spacecraft, and you really need a very dedicated spacecraft that was designed only for that purpose," said another co-author of the Science study, Bruce Macintosh of the Lawrence Livermore National Laboratory in California.

Barman said it might be possible to detect variations in the surface brightness of extrasolar planets using next-generation, ground-based instruments such as the Gemini Planet Imager. "We might be able to do that within the next few years," he said.

How were planets formed?
The researchers said the readings from OSIRIS also could provide insights into how the planetary system was formed. Theorists have proposed two scenarios for the formation of planets from the disk of gas and dust surrounding an infant star. In the core-accretion scenario, planets form gradually as solid cores grow massive enough to start taking on envelopes of gas from the disk. In the gravitational-instability scenario, planets form almost instantly as parts of the disk collapse on themselves.

"For the first time, we can actually make a statement, a suggestion about the way the system might have formed, which is an extremely difficult thing to do observationally," said the study's lead author, Quinn Konopacky, an astronomer at the University of Toronto's Dunlap Institute for Astronomy and Astrophysics.

The ratio of carbon to oxygen was higher than would have been expected if the planet shared the composition of its parent star and protoplanetary disk. That might have happened because the disk's gas cooled gradually over time, forming water ice that depleted the oxygen from the gas that remained. This is the way most astronomers believe our own solar system formed.

"Once the solid cores grew large enough, their gravity quickly attracted surrounding gas to become the massive planets we see today," Konopacky said in a news release. "Since that gas had lost some of its oxygen, the planet ends up with less oxygen and less water than if it had formed through a gravitational instability."

Not all astronomers think the case is that clear-cut, however. Alan Boss, a theoretical astrophysicist at the Washington-based Carnegie Institution for Science, told NBC News that giant planets as far away from their parent stars as HR 8799c were more likely to be formed through gravitational instability than through core accretion.

In any case, Boss said he doubted that the readings from OSIRIS could rule out either scenario for planetary formation, since so much depends on the details of a particular theory. "Theorists are clever," he said. "It's hard to paint them into a corner."

More about planets:

• Sun's shock waves may have staggered planet formation
• Cosmic wreckage hints at our planet's eventual fate
• NBC News archive on planetary science

The authors of the Science study, "Detection of Carbon Monoxide and Water Absorption Lines in an Exoplanet Atmosphere," include Christian Marois as well as Konopacky, Barman and Macintosh.

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

E. Guido / G. Sostero / N. Howes

The crosshairs at the center of this false-color image highlight Comet C/2012 S1 (ISON), which has the potential of becoming as bright or brighter than the full moon in late 2013. Right now, its brightness in the constellation Cancer is around magnitude 18, which would require a 16- to 20-inch telescope for sighting.

A new comet superstar named C/2012 S1 (ISON) is heading for the spotlight starting in November 2013 — but will it perform as some hope it will, or will it be a dud of cosmic proportions?

"This is one to watch, definitely," said Karl Battams, a scientist at the Naval Research Laboratory who monitors comets for the NASA-supported Sungrazer Comet Project. "But the astronomy community in general tries not to overhype these things. Potentially it will be amazing. Potentially it will be a huge dud."

Comet ISON quickly rose to the top of the charts after its discovery, which was based on imagery collected on Friday by the International Scientific Optical Network's 16-inch (0.4-meter) Santel reflecting telescope in Russia. The comet, which was described in an IAU circular on Monday, takes its common name from the network's acronym. Since the discovery, astronomers have gone back through their files to find "pre-discovery" images and calculate the comet's orbit.

That orbit is due to bring Comet ISON incredibly close to the sun — within just 1.1 million miles (1.8 million kilometers) in late November of next year. As a result, current projections suggest it could get very bright. How bright? Various estimates have set the brightest magnitude at -10 to -16. That suggests the comet could become brighter than the full moon — which led Astronomy Magazine's Michael E. Bakich to say it "probably will become the brightest comet anyone alive has ever seen."

Over the next year, you're going to hear a lot of comparisons to stunners of the past, as long ago as the Great Comet of 1680 and as recent as the Great Comet of 2007. You'll also hear comparisons to past letdowns, ranging from Comet Kohoutek to Comet Elenin. You may also hear a fresh wave of doomsday talk, like the ridiculous rumblings that accompanied Elenin's approach.

Don't believe anything you hear about a comet catastrophe — and don't get your hopes up just yet for a comet extravaganza. But do make plans to keep an eye on the sky in late 2013.

Battams said a lot depends on Comet ISON's composition. "It could turn into a huge letdown if it's a comet that's just too fragile and dissipates as it makes its way into the inner solar system," he told me. That's basically what happened to Comet Elenin. Because ISON appears to be a "new" comet coming in from the far-flung Oort cloud, it's tough to predict how the comet will behave.

The comet is currently in the constellation Cancer, as indicated in this star chart from Astronomy Magazine. When the comet hits prime time, a year from now, it should be heading through the constellation Virgo and visible from northern latitudes before sunrise. Here's a night-sky animation from the Remanzacco Observatory that shows how things are likely to go down. 

During the months ahead, astronomers of all stripes will be keeping a watch on Comet ISON and refining their expectations. "I would imagine that by next summer, we should have a much better handle on it," Battams said. In the meantime, check out the chatter on SpaceWeather.com, the Remanzacco Observatory's comet blog and the Comets Mailing List. (And on Twitter, keep an eye on @SungrazerComets.) 

More on comets:

• Comet PANSTARRS due to light up in 2013
• What's up with these sun-diving comets?
• Comet turns into a Christmas star
• Flash interactive: Inside a comet

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

(c) Martin Pugh

This picture of the Whirlpool Galaxy, also known as M51, won top honors in the Deep Space category and the overall competition for 2012 Astronomy Photographer of the Year. The picture was entered by British-Australian photographer Martin Pugh. Here's what the Royal Observatory says: "This beautifully composed image of the Whirlpool Galaxy combines fine detail in the spiral arms with the faint tails of light that show its small companion galaxy being gradually torn apart by the gravity of its giant neighbour. A closer look shows even more distant galaxies visible in the background."

The Whirlpool Galaxy is one of the most photogenic spirals in the known universe, but not all whirlpools are created equal: Australian photographer Martin Pugh's view of the galaxy, also known as M51, was stunning enough to win him the top prize in the Royal Observatory's Astronomy Photographer of the Year competition.

"It's a remarkable achievement by an amateur astronomer; one of the best images of M51 that I've seen," Marek Kukula, the Royal Observatory's public astronomer and one of the contest judges, said in a news release. More than 800 entries were submitted, and the observatory announced the winners on Wednesday night.

Pugh said via Flickr that he was "absolutely delighted" by the honor — but for him, this isn't exactly a novel experience: He also won top honors in the 2009 competition. 

Sir Patrick Moore, who's best-known for his British TV programs on astronomy, was impressed by the level of professionalism that today's amateurs bring to their sky snapshots. "Many of the pictures have been taken with equipment that was out of the range of the amateur many years ago," he said. "I also like the choice of subjects: photographing people and the night skies is very difficult. The entrants have done very well indeed."

Take a look at these winners, and then click your way through all the favorites at the Royal Museums Greenwich website. You can also scan through thousands of archived entries at the APotY Flickr gallery, and see the photo exhibition at the Royal Observatory through February.

(c) Masahiro Miyasaka

Japan's Masahiro Miyasaka won top honors in the Earth and Space category with this shot of Orion, Taurus and the Pleiades shining in the night sky above an icy landscape. The category is for photos that include "Earthly" things along with an astronomical subject. Miyasaka's entry, titled "Star Icefall," included a poem about the view: "The stars fell from the heavens. / The stars transformed themselves into an icicle. / Stars sleep eternally here."

(c) Chris Warren

The sun shines through the clouds during June's transit of Venus, as seen in this prize-winning photo from Britain's Chris Warren. The picture, captured through a hydrogen-alpha filter, won top honors in the Our Solar System category. Venus is visible as a black spot toward the sun's upper right edge."Our first and only glimpse of the transit before third contact, through a thin patch in the clouds at Blackheath in London," Warren writes.

(c) Jacob von Chorus

Fifteen-year-old Jacob von Chorus of Canada won top honors in the Young Astronomy category with this view of the Pleiades star cluster. "This image was a test to see what would happen with such a long exposure," von Chorus writes. "It was taken near dusk, with only two frames and an hour of exposure. This image has since become one of my best." The Young Astronomy category is for photographers under 16 years of age.

(c) Laurent Laveder

France's Laurent Laveder won a special award for this photo of a Venus-Jupiter conjunction on March 15, taken on the beach at Tréguennec in northwest France. "In this image, Venus is higher and on the right of Jupiter," Laveder writes. "I take my place in the lower right corner of the frame to complete the diagonal formed by me, the two planets, the Pleiades and Taurus. With my red flashlight on my head, I illuminate the beach. At low tide, the sand is wet and is reflecting the blockhouse." Laveder won the People and Space award, for photos that include people in a creative way.

(c) Lorand Fenyes

Hungary's Lóránd Fényes won the Best Newcomer award, reserved for photographers who have taken up the hobby in the past year and have not entered an image in the competition before. This picture shows the Elephant's Trunk nebula, seemingly uncoiling within the star cluster IC 1396 in the constellation Cepheus. "The Elephant's Trunk is my 34th photo," Fényes writes.

(c) Thomas Read

Twelve-year-old Thomas Read of Britain won the Robotic Scope prize with this view of the Sunflower Galaxy (M63), captured online using the Bradford Robotic Telescope in Tenerife. "I love this image, as it shows fantastic detail in the spiral arms," Read writes. "I was curious about the Sunflower Galaxy and how to maximize photographic results for a distant galaxy." The award goes to images taken by robotic or remote telescopes and then processed by the entrant.

More marvelous astronomy shots:

• Slideshow: The World at Night 2012
• MSN UK: Astronomy Photographer of the Year 2011
• Slideshow: Astronomy Photographer of the Year 2010
• All-time top 10 from Astronomy Picture of the Day
• Space Gallery at NBCNews.com

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ circles. To keep up with Cosmic Log and NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, sent to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the dwarf planet and the search for new worlds.

In case you need another reason to dream about a vacation down under, check out this stunning time lapse video of the Milky Way seen over the Southern Ocean made by amateur astronomer Alex Cherney of Melbourne, Australia.

The video compresses 31 hours of viewing time into 2.5 minutes that show our galaxy rising and setting over the ocean as clouds sweep across the skies and distant ships blink on the horizon. Beyond the Milky Way, the Magellanic clouds rise and moonrise illuminates Australia's south coast.

Cherney's effort won the grand prize in the STARMUS astrophotography competition. "The scenes are chosen with the eye of an artist, but the subtle panning and excellent control of color and contrast reveal technical skills of a high order," the organizers of the astronomy festival said in a news release announcing the winner.

More stunning time lapse imagery:

• See a meteor shower in a minute
• Time flies … in one-year videos
• Video: Photographer captures stunning time lapse of stars
• The Milky Way from South Dakota

Tip o' the Log to Wired Science

John Roach is a contributing writer for msnbc.com. Connect with the Cosmic Log community by hitting the "like" button on the Cosmic Log Facebook page or following msnbc.com's science editor, Alan Boyle, on Twitter (@b0yle).

It seems that the world was shocked to learn this week that astrology no longer reflects astronomical realities. But such shifts are merely part of the routine in a changing universe. They don't always come to our attention, but they can make more of a difference in your daily life than your horoscope.

Parke Kunkle, an astronomer who teaches at Minneapolis Community and Technical College, set off an Internet-wide viral buzz when the Star-Tribune published his observation that the constellations don't match the traditional astrological signs. Back in the days of Babylonian soothsayers, the sun might have been in the constellation Capricorn at this time of year. But due to the changing tilt of Earth's axis, it's actually in Sagittarius right now.

Today, Kunkle told MSNBC that his phone has been ringing off the hook — and he doesn't know why this has turned into such a big deal. "What we've been doing is just a standard astronomy lesson that we talk about in every astronomy class," he said.

Over the course of thousands of years, Earth's axis wobbles like a top, and as a result the apparent position of the sun against the constellations varies. The boundaries of the constellations have become more sharply defined as well, which means the sun doesn't spend equal amounts of time in each of the zodiacal "signs." In fact, the sun passes through a 13th constellation — Ophiuchus the serpent bearer — which throws off the whole traditional 12-house system that astrologers swear by.

Of course, most people don't give any credence to astrology, with or without Ophiuchus. A 2005 Gallup Poll found that only about a quarter of Americans believe that the position of stars or planets can affect their lives. And even if you are a believer, the planetary shift doesn't magically transform you from a Virgo to a Leo. "This doesn't change your chart at all," Shelly Ackerman, an astrologer and spokeswoman for the American Federation of Astrologers, told The Associated Press.

The same advice holds for other astrological systems. For example, it's still the Chinese Year of the Tiger (well, at least until February). The fact is that the practice of astrology is separate from the modern science of astronomy, even though ancient cultures spent so much effort on astronomy mainly so that astrologers could do their job better.

Earth's cosmic shifts have had other effects as well. Just for luck, here are seven examples:

Changing pole star: Another effect of Earth's wobbling axis is that different stars have served as the guide star for our planet's geographical north pole throughout history. During the heyday of the Egyptian pharaohs, for example, other stars took on the role of the pole star, an "undying" star that never set. This is thought to be the reason why the Great Pyramid of Khufu was built with a passageway that pointed to the star Thuban in the constellation Draco, which was the star closest to the north pole when Khufu died, around 2566 B.C. Later on, the pole stars were  Kochab and Pherkad in the constellation Ursa Minor. Today it's Polaris, but the bright star Vega had its turn around 12,000 B.C. and will be the pole star once again in the year 13,727 or so.

Changing magnetic poles: Last week's big geophysical story had to do with the gradual shift of Earth's magnetic north pole away from Canada and toward Russia. The poles move because of the changing flow of molten iron in Earth's core, which drives the planet's huge magnetic dynamo. This doesn't affect Earth's spin or geographical north, but it does cause the structure of the magnetic field to shift, which affects compasses. Although a lot of navigation nowadays is done using GPS systems, the Federal Aviation Administration wants to make sure that aviators can still find their way to a safe landing using magnetic compasses — and that's why it requires airports to revise their runway designations periodically to reflect the magnetic shift.

Shifting continents: Earth's continents are on the move as well, and over the course of millions of years, that has affected the course of evolution. "The continents are drifting at about the same rate that your fingernails are growing," Phil Plait, the astronomer who presides over the Bad Astronomy blog, told me. If you go back 180 million years or so, nearly all of Earth's land mass was united in one large continent called Pangea, which meant land-based organisms could spread far and wide. Since then, the continents have drifted apart, separating populations and leading to the rise of new species. The breakup of Pangea helps explain why kangaroos thrived in Australia but not America.

Uneven gravity: Just as Earth's magnetic field has its variations, so does Earth's gravitational field. Readings from the European Space Agency's GOCE satellite have plotted the subtle differences in our planet's mass distribution, on land and in the oceans. "You'd think gravity is the same everywhere, until you start delving really deep into it," said Alice Enevoldsen, planetarium supervisor at the Pacific Science Center in Seattle (and the blogger behind Alice's Astro Info). Variations in Earth's mass could help explain how ocean circulation works and lead to better climate prediction models.

Inconstant sun: Speaking of climate, the variations in solar irradiance play a significant role in the warming and cooling trends experienced on our planet as well as on others. Some suggest that the sun is a bigger factor than human industrial activity when it comes to global climate change. Most climate scientists say greenhouse-gas emissions have been playing a more significant role lately, but variations in the amount of solar radiation hitting the planet are definitely a factor as well. Last year, one study found that the amount of solar energy reaching Earth increased even though the sun was at the low point in its 11-year activity cycle. And just today, scientists reported that the solar energy levels were actually lower than previously thought.

Lengthening day: If it seems as if each day is longer than the last, you're right. But that's just because Earth is slowing down ever so slightly every day. Gravitational tugs from other celestial bodies (principally the moon and the sun) are causing the "great slowdown," as my colleague David Ropeik explained back in 2001. It's thought that when the moon formed, billions of years ago, a full day was six hours long, and that the day lasted less than 23 hours when dinosaurs ruled the earth. Nowadays, leap seconds are periodically added to keep atomic clocks in sync — most recently at the end of 2008.

Galactic tides: Our solar system's path through the Milky Way galaxy is subject to shifts as well. Scientists have noted that Earth's biodiversity seems to dip every 60 million years or so, at just about the time when the solar system bobs up through the average plane of the Milky Way's disk. Last month, researchers suggested that the rise through the galactic plane exposed the solar system to a surge of cosmic rays, dealing a damaging blow to life on Earth. Some scientists have also wondered whether the solar system's galactic oscillations might periodically send more comets into the solar system (killing off, let's say, the dinosaurs). This definitely sounds like a bad thing, and depending on who's doing the talking, we're either "very close" to the next risky period, or 10 million years away.

That puts this whole question over whether you're a Virgo or a Leo in perspective, doesn't it?

Update for 2:30 p.m. ET Jan. 15: I initially wrote that astrology is "totally divorced" from modern astronomy, but that's an overstatement. Astrologers still depend on accurate determinations of celestial bodies' positions in the sky, as seen from Earth. They incorporate astronomical advances as well, such as the discovery of additional dwarf planets. But the way they interpret that information is different from how astronomers would interpret it.

Take the constellations, for example: Some commenters have noted that when an astrologer says the sun is "in the house of Aries," that doesn't mean the sun is actually in the astronomical constellation of Aries. In astrology, the sun enters Aries at the time of the March equinox, as explained here by EarthSky. The sky is then divided into 12 houses (named after constellations) that take up equal amounts of angular distance around the celestial equator. Thus, the astrological signs do not correspond precisely with the astronomical constellations as they're defined today, and they never did.

In ancient times, the "first point of Aries" occurred when the sun was actually in the astronomical constellation of Aries. No more. Now the sun is in the constellation of Pisces for the March equinox, and by the time Earth wobbles its way to the year 2600 it will be in Aquarius for the start of northern spring. For astronomers, that will be the true dawning of the age of Aquarius, although some astrologers (and songwriters) argue that the Aquarian age has already begun.

Astrologers borrow quite a bit from astronomy, but generally speaking, the only professional interest that astronomers take in astrology is historical — since, as noted above, the roots of astronomy go back to ancient beliefs about the connections between the cosmos and our destinies. It's a natural human yearning. I'll bet that at least one or two young astronomers have checked their "love signs" at some point, even if they haven't written a research paper about it.

More on scientific paradigm shifts:

• Technolog: How Twitter snowballed the zodiac 
• Vote: Has your opinion of astrology changed?
• Scientists give the periodic table a makeover
• Earth's timeline: How continents clashed
• Scientists question fundamental laws

Connect with the Cosmic Log community by "liking" our Facebook page, or by following msnbc.com's science editor, Alan Boyle, on Twitter (@boyle).