Video: Planets galore, including super-Earths

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updated 9/13/2011 9:21:09 PM ET 2011-09-14T01:21:09

The recent rapid pace of discovery of "candidate planets" — distant worlds that seem suitable for life — make scientists engaged in the search for extraterrestrial intelligence, or SETI, hopeful that they could find alien signals within the next 15 years.

On Monday, astronomers at the European Southern Observatory in Chile announced the discovery of 16 new "super-Earths," planets orbiting distant stars that are smaller than gas giants and most likely have rocky surfaces where life could gain traction. The strongest candidate among the newfound super-Earths is known as HD 85512b: It resides in its star's "habitable zone," where the temperature could be just right to sustain liquid water — the elixir of life as we know it.

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The 16 new candidates join a list of 54 others discovered earlier this year by NASA's Kepler spacecraft.

On target
The SETI Institute in Mountain View, Calif., home of the best-known effort to seek extraterrestrial signals, was forced to shut down its radio telescopes in April due to funding shortages, but charitable donations are bringing the telescopes back online at this very moment. When the SETI team resumes its radio signal-scouring next week, the new super-Earths will be first on its telescope target list. [A Field Guide to Alien Planets]

"When the array is again operational we will go back to our exploration of exoplanets," Jill Tarter, director of the Center for SETI Research at the institute, told Life's Little Mysteries. Unfortunately, HD 85512b is too far south to be targeted by the Allen Telescope Array, SETI's main detector. "We will, however, add those exoplanets reported by [ESO] that are visible to our list of targets. The more planets the better!"

After the scientists aim their telescope array toward a new exoplanet, it takes a few months to determine whether any of the radio signals coming from it are products of intelligent design — that is, alien-made — rather than just natural cosmic noise and planetary rumblings.

"The results over all frequency bands [come in over the course of] months as we systematically go through the list," Doug Caldwell, Kepler instrument scientist at the SETI Institute, explained in an email.

Though SETI astronomers could find life on their very next try, doing so will probably require scouring the skies for years. Frank Drake, the SETI Institute's chairman emeritus and a pioneer in the field, compared searching for ET to playing the lottery. "It depends on the rate at which we search," Drake wrote in an email. "Discoveries of other civilizations are surely few and far between. You have to make many tries, just as winning the lottery requires the purchase of many tickets."

So how many tickets does the SETI team have to buy before they'll hear E.T. phoning home?

Fifteen to 20 years
Scientists use an equation formulated by Drake in the 1960s to estimate how long it will take to find intelligent life. The Drake Equation determines the number of intelligent and signal-transmitting civilizations in our galaxy by multiplying a string of factors, including the number of stars, the fraction of those that have planets, the fraction of those that are habitable, the probability of life arising on such planets, the likelihood of that life becoming intelligent, and so on.

The values of many of these factors are highly speculative, but Drake himself estimated their product to be 10,000 — as in, there are 10,000 civilizations transmitting signals in our galaxy at any given moment. Because there are 100 billion stars in the galaxy, the math says one in 10 million star systems will be sending radio signals our way at any given time.

Use our Drake Equation calculator to estimate the odds for E.T.

By making smart choices about which stars are likely to sustain life, we should be able to find someone or something by searching just 1 million stars, Drake originally estimated. That could take SETI, as it currently operates, as little as two decades. [Will We Really Find Alien Life Within 20 Years?]

However, that estimate predated the recent boom in exoplanet discoveries. "It was not long ago that we had only wild guesses about the number of stars with planets," said Gerald Harp, an astrophysicist at the SETI Institute. "I believe our earlier guesses were too low — a large proportion of stars are now believed to host Earth-like planets. We now know that perhaps 1 percent of stars have planets where biological life may arise. We also know where some of those planets are."

Considering this new information, Harp thinks scientists will  have to search only 100,000 stars before detecting alien signals, and that they'll manage to examine that many in the next 15 years. "Fortunately for me, I expect to still be actively pursuing research in 15 years, so I will be around when it happens!" Harp said.

Not everyone is as willing to nail down a timeline, though they're all hopeful. "While I don't know if we will discover intelligent life — or any life — in the next 20 years, I'd hesitate to bet against it, given the amazing pace of development in the fields of astrobiology and extrasolar planets, both of which barely even existed 15 years ago," Caldwell wrote.

Similarly, Tarter wrote, "I'm not inclined to put a timetable on success. I don't bet on horses or football pools, either."

Follow Natalie Wolchover on Twitter @nattyover. Follow Life's Little Mysteries on Twitter @llmysteries, then join us on Facebook.

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Photos: Month in Space: January 2014

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  1. Southern stargazing

    Stars, galaxies and nebulas dot the skies over the European Southern Observatory's La Silla Paranal Observatory in Chile, in a picture released on Jan. 7. This image also shows three of the four movable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: They reveal details that would otherwise be visible only through a telescope as large as the distance between them. (Y. Beletsky / ESO) Back to slideshow navigation
  2. A balloon's view

    Cameras captured the Grandville High School RoboDawgs' balloon floating through Earth's upper atmosphere during its ascent on Dec. 28, 2013. The Grandville RoboDawgs’ first winter balloon launch reached an estimated altitude of 130,000 feet, or about 25 miles, according to coaches Mike Evele and Doug Hepfer. It skyrocketed past the team’s previous 100,000-feet record set in June. The RoboDawgs started with just one robotics team in 1998, but they've grown to support more than 30 teams at public schools in Grandville, Mich. (Kyle Moroney / AP) Back to slideshow navigation
  3. Spacemen at work

    Russian cosmonauts Oleg Kotov, right, and Sergey Ryazanskiy perform maintenance on the International Space Station on Jan. 27. During the six-hour, eight-minute spacewalk, Kotov and Ryazanskiy completed the installation of a pair of high-fidelity cameras that experienced connectivity issues during a Dec. 27 spacewalk. The cosmonauts also retrieved scientific gear outside the station's Russian segment. (NASA) Back to slideshow navigation
  4. Special delivery

    The International Space Station's Canadian-built robotic arm moves toward Orbital Sciences Corp.'s Cygnus autonomous cargo craft as it approaches the station for a Jan. 12 delivery. The mountains below are the southwestern Alps. (NASA) Back to slideshow navigation
  5. Accidental art

    A piece of art? A time-lapse photo? A flickering light show? At first glance, this image looks nothing like the images we're used to seeing from the Hubble Space Telescope. But it's a genuine Hubble frame that was released on Jan. 27. Hubble's team suspects that the telescope's Fine Guidance System locked onto a bad guide star, potentially a double star or binary. This caused an error in the tracking system, resulting in a remarkable picture of brightly colored stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288. (NASA / ESA) Back to slideshow navigation
  6. Supersonic test flight

    A camera looking back over Virgin Galactic's SpaceShipTwo's fuselage shows the rocket burn with a Mojave Desert vista in the background during a test flight of the rocket plane on Jan. 10. Cameras were mounted on the exterior of SpaceShipTwo as well as its carrier airplane, WhiteKnightTwo, to monitor the rocket engine's performance. The test was aimed at setting the stage for honest-to-goodness flights into outer space later this year, and eventual commercial space tours.

    More about SpaceShipTwo on PhotoBlog (Virgin Galactic) Back to slideshow navigation
  7. Red lagoon

    The VLT Survey Telescope at the European Southern Observatory's Paranal Observatory in Chile captured this richly detailed new image of the Lagoon Nebula, released on Jan. 22. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of 11 public surveys of the sky now in progress using ESO telescopes. (ESO/VPHAS team) Back to slideshow navigation
  8. Fire on the mountain

    This image provided by NASA shows a satellite view of smoke from the Colby Fire, taken by the Multi-angle Imaging SpectroRadiometer aboard NASA's Terra spacecraft as it passed over Southern California on Jan. 16. The fire burned more than 1,863 acres and forced the evacuation of 3,700 people. (NASA via AP) Back to slideshow navigation
  9. Where stars are born

    An image captured by NASA's Spitzer Space Telescope shows the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This false-color infrared view, released on Jan. 15, spans about 40 light-years across the region. The brightest portion of the nebula is centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But Spitzer also can detect stars still in the process of formation, seen here in red hues. (NASA / JPL-Caltech) Back to slideshow navigation
  10. Cygnus takes flight

    Orbital Sciences Corp.'s Antares rocket rises from NASA's Wallops Flight Facility on Wallops Island, Va, on Jan. 9. The rocket sent Orbital's Cygnus cargo capsule on its first official resupply mission to the International Space Station. (Chris Perry / NASA) Back to slideshow navigation
  11. A long, long time ago...

    This long-exposure picture from the Hubble Space Telescope, released Jan. 8, is the deepest image ever made of any cluster of galaxies. The cluster known as Abell 2744 appears in the foreground. It contains several hundred galaxies as they looked 3.5 billion years ago. Abell 2744 acts as a gravitational lens to warp space, brightening and magnifying images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang. (NASA / NASA via AFP - Getty Images) Back to slideshow navigation
  12. Frosty halo

    Sun dogs are bright spots that appear in the sky around the sun when light is refracted through ice crystals in the atmosphere. These sun dogs appeared on Jan. 5 amid brutally cold temperatures along Highway 83, north of Bismarck, N.D. The temperature was about 22 degrees below zero Fahrenheit, with a 50-below-zero wind chill.

    Slideshow: The Year in Space (Brian Peterson / The Bismarck Tribune via AP) Back to slideshow navigation
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Explainer: SETI: 50 years of searching for E.T.

  • Somewhere out there, alien civilizations might be communicating with each other. They might even be trying to contact us. In 1960, this reasoning compelled astronomer Frank Drake to point a radio telescope at the stars and listen for chatter. He didn't hear E.T. calling us, calling home, or calling anywhere else during his four-month-long experiment at the National Radio Astronomy Observatory in Green Bank, W.Va., but the effort officially kicked off what is known as SETI, the search for extraterrestrial intelligence. Click the "Next" label to check out highlights from the first 50 years of the search.

    — By John Roach, msnbc.com contributor

  • 1974: Earthlings send message to aliens

    By 1974, Drake and his colleagues still hadn't heard anything from ET, but they hadn't given up hope. Instead, they sent a message out to the aliens with the Arecibo radio telescope in Puerto Rico, the first deliberate message sent from Earth out to the stars. The message contained information about life-giving chemicals, DNA, a simple drawing of our solar system, and pictures of human beings and the Arecibo telescope. The string of 1's and 0's was sent to a group of about 300,000 stars in called the Great Cluster in Hercules, Messier 13, about 25,000 light years away.

  • 1977: The Wow Signal

    Courtesy of Jerry Ehman / Bigear

    Did E.T. make a prank call to Earth on Aug. 15, 1977? We may never know for sure, but astronomer Jerry Ehman was struck enough by a string of letters and numbers on a printout of radio data from the Big Ear Radio Observatory at Ohio State University to scribble "Wow!" in the margin. The extraordinary signal might have been E.T., or something else. Whatever it was, astronomers have been unable to find it again despite dozens of searches, leaving open the possibility that E.T. called but hung up after the first ring.

  • 1992-1993: NASA's brief search

    U.S. Senate Historical Office

    Exactly 500 years after Christopher Columbus arrived in the New World, NASA officially launched its SETI program, the High Resolution Microwave Survey. Experts called it the most ambitious and technologically advanced alien-search effort ever conducted, but after just a year of operation the program was squashed. Sen. Richard Bryan, D-Nev., shown here, led the effort to kill the program, telling the Senate that "millions have been spent and we have yet to bag a single little green fellow. Not a single Martian has said take me to your leader, and not a single flying saucer has applied for FAA approval."

  • 1995: Project Phoenix rises from ashes

    Image: Paraffin candles
    Seth Shostak / SETI Institute

    When NASA funding for alien searches ran dry, private enterprise picked up the pieces - including some of NASA's equipment - and launched Project Phoenix. The targeted search focused on about 1,000 stars thought most likely to harbor alien civilizations and was conducted at various radio astronomy observatories around the world. In this image, SETI Institute astronomer Seth Shostak looks for E.T.'s call on a computer bank at the Arecibo observatory in Puerto Rico.

  • 1999: SETI for the masses

    SETI @ Home / UC-Berkeley
    Five million Internet users have contributed more than 3 million years of processing time to the search for signals from extraterrestrial civilizations through the SETI @ Home screensaver program, shown here.

    Hundreds, then thousands, and ultimately millions of computer users around the world got in on the search for E.T. with the 1999 launch of SETI@home, a distributed computing project run at the University of California at Berkeley. The program enlists personal computers to sort through the mountains of SETI data, one chunk at a time, collected by the Arecibo radio telescope. The combined power of all the computers running the program essentially acts like a super duper supercomputer, but at a fraction of the cost.

  • 2007: Telescope array turned on

    For most of the past 50 years, SETI projects have required astronomers to wait in line for time on giant radio telescopes around the world. That changed in 2007 with the opening of the Allen Telescope Array, a constellation of 42 radio telescopes with 20-foot-wide dishes in the scrublands about 300 miles northeast of San Francisco. The array, privately financed by software billionaire Paul Allen and others, puts the search for E.T. front and center. The project is jointly run by the SETI Institute and the University of California at Berkley. In the coming decades the array may grow to 350 antennas, making it one of the most powerful radio telescopes in the world.

  • The future of SETI

    NASA
    An artist's interpretation of the Kepler observatory in space. Credit: NASA

    As of this writing, extraterrestrials remain elusive, assuming that they exist at all. Given that the search is only 50 years old, many astronomers see little reason to despair - things are just getting going. NASA recently lent a new hand to the search with its Kepler mission, a space telescope that is looking for Earthlike, habitable planets around thousands of stars in our Milky Way galaxy. Detection of these planets will help SETI scientists focus their efforts.

    Other ideas include a push to expand the search beyond just radio signals. Paul Davies, a physicist at Arizona State University and author of several popular science books, argues that messages from E.T. might even be floating around in the junk DNA of terrestrial organisms and that we should start searching decoded genomes for the biotech equivalent of a message in a bottle.

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