Image: Alpha Centauri B
L. Calcada / N. Risinger / ESO
An artist's conception shows the planet orbiting Alpha Centauri B, a member of the triple-star system that's closest to Earth. Alpha Centauri B is the most brilliant object in the sky, with Alpha Centauri A at lower left and our own sun visible as a bright speck at upper right.
updated 10/18/2012 6:08:33 PM ET 2012-10-18T22:08:33

The recent discovery of an Earth-size alien planet right next door to us could help spark humanity's first true steps beyond our own solar system, scientists say.

On Tuesday, a European team announced the existence of Alpha Centauri Bb, a roasting-hot world residing in the nearest star system to our own, just 4.3 light-years away. The find could spur serious and sustained efforts to explore the newfound planet and any siblings it may have in the three-star Alpha Centauri system, say researchers not involved in the discovery.

"This is a huge motivator for the future of sending probes outside of our planetary system and humans trying to figure out how to travel to another star system," MIT planetary scientist Sara Seager told via email. "I think the reality of a planet and the promise of more is a game changer."

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An exciting find
The astronomers found Alpha Centauri Bb, which is about 13 percent more massive than Earth, using the High Accuracy Radial velocity Planet Searcher, an instrument on a telescope at the European Southern Observatory's La Silla Observatory in Chile. [ Gallery: Nearby Alien Planet Alpha Centauri Bb ]

The news came as a surprise to some in the exoplanet community.

"It reads like Poe’s short story 'The Purloined Letter' where Nature has hidden one of the most sought-after jewels in the field of exoplanet science in plain sight," said Jon Jenkins of NASA's Ames Research Center and the SETI (Search for Extraterrestrial Intelligence) Institute.

"It’s quite a cosmic joke to think that we’ve been spending decades planning missions and observations to find Earth-mass planets orbiting much more distant stars and Nature hides an Easter egg just beside us," added Jenkins, who is analysis lead for NASA's prolific planet-hunting Kepler Space Telescope.

The planet orbits extremely close to its host star Alpha Centauri B, completing one lap every 3.2 days. As a result, its surface is far too hot to support life as we know it.

But recent exoplanet detections, including many by Kepler, show that small, rocky worlds like Alpha Centauri Bb tend to be found in multiplanet systems.

"So, this would imply the chances are high that this star has other planets farther out, and perhaps one might be in the habitable zone," said David Charbonneau of the Harvard-Smithsonian Center for Astrophysics, referring to that just-right range of distances around a star that can support the existence of liquid water.

Future space telescopes — such as NASA's proposed Terrestrial Planet Finder and the European Space Agency's Darwin instrument — could search for signs of life on promising worlds that may neighbor Alpha Centauri Bb, said veteran planet hunter Geoff Marcy of the University of California, Berkeley.

"Those missions can not only image planets in the habitable zone but take spectra of them, to assess the chemical composition of the atmosphere of the planet," Marcy told via email. "There is a prospect, with planets around Alpha Cen B, to search for bio-signatures in the atmosphere of any planets in the habitable zone."

Interstellar exploring
That would be exciting enough. But Marcy and some of his colleagues hold out hope that humanity will get a much closer look at the Alpha Centauri system someday — and they think now is a good time to get the ball rolling.

"There is now great impetus to send a probe with a camera to Alpha Cen to study the three stars there (including Proxima Centauri) and to study the planets and moons there," Marcy said. "What a rich opportunity for NASA and ESA, working with all nations on Earth, to send a probe to Alpha Centauri, galvanizing interest from people of all ages around the world."

Such a mission is not practical with today's spacecraft, which would take tens of thousands of years to travel the 25 trillion miles to Alpha Centauri. So researchers will have to come up with new, superfast propulsion systems — perhaps nuclear rockets, antimatter fusion drives or another such advanced technology in the early stages of development today.

Marcy thinks the world should aim to launch a robotic spacecraft toward Alpha Centauri by the year 2100.

"The president of the United States, after his election in November, should lead a vigorous new NASA program," he said. "We should study the prospective propulsion methods that can launch a probe to Alpha Cen before the century is out, returning data back safely to Earth."

The time may be right to start laying the groundwork for such an ambitious mission. The world is buzzing about Alpha Centauri Bb, a planet found in a star system familiar to many people from countless sci-fi novels, TV shows and films.

"Knowing that these distant horizons exist will inspire generations of explorers," said Natalie Batalha, deputy leader of the Kepler science team at NASA Ames.

"Why climb the mountain? Because it exists," she told "That's the human spirit, and it brings with it infinite possibilities — for practical things like technology that improves the human condition and the reality of interstellar exploration but also for lofty things like evolution and global cooperation and who knows — maybe even knowledge of other life in the universe. One can dream."  

Follow senior writer Mike Wall on Twitter @michaeldwallor @Spacedotcom. We're also on Facebookand Google+.

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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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