Tractor beams, a common theme in science fiction fantasy, may one day become science fact. Researchers at Singapore’s Agency for Science, Technology and Research (A*STAR) may have devised a way to create a real-life tractor beam that could potentially one day be used to manipulate biological cells.

Don't get your hopes up for a spaceship pulling tractor beam laser just quite yet.

From the work of Albert Einstein and Max Planck, we know that light pushes objects away. A tractor beam requires the opposite motion, so that objects are pulled toward the initiating point of the beam of light. So far, creating a backwards force with a forward-moving beam has proven quite difficult.

However, A*STAR researchers may now have the answer by creating the backwards motion on a small scale.

"Our work demonstrates a tractor beam based only on a single laser to pull or push an object of interest toward the light source,” said Haifeng Wang, who has been working on the project.

The key to the project is a special type of laser that creates a particular distribution of light intensity; the emission is called a Bessel beam. When the laser hits a small particle in its path, instead of scattering light backwards, which pushes the particle forwards, the light scatters forwards off the particle, effectively pushing the object backwards to the point of origin.

This is not the first time Bessel beams have been tested. In 2006, Washington State University researchers used Bessel beams on sound waves and described a similar backwards pull.

In March 2011, scientists in Hong Kong further developed the idea of how a Bessel beam could be used to pull objects closer, and last November NASA embarked on a $100,000 research study to develop real-life tractor beams, using three different methods. One of NASA's approaches involved the Bessel beam, but at the time, its backwards pull was only a theory.

"According to theory, the laser beam could induce electric and magnetic fields in the path of an object. The spray of light scattered forward by these fields could pull the object backward, against the movement of the beam itself," NASA's Lori Keesey wrote in a press release.

A*STAR's experiment may be the first reported success of the Bessel beam in action.

Although Wang and his team have only seen this phenomenon work on tiny particles thus far, further studies could apply the tractor beam technology to other things -- biological cells, for one. However, larger objects are out of the question since the laser's beam would cause severe damage.

"These beams are not very likely to pull a human or a car, as this would require a huge laser intensity that may damage the object,” Wang said. “However, they could manipulate biological cells because the force needed for these doesn’t have to be large.”

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For more interesting research feats, check out the gallery below to see NASA's biggest discoveries of 2011.
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  • Entire Sun Imaged

    In February, <a href="http://www.nasa.gov/mission_pages/stereo/main/index.html" target="_hplink">NASA's STEREO probes</a>, two observatories that were launched in 2006 to survey the sun, reached opposite ends of the sun and thus, were able to give scientists (and the rest of us!) a never-before-seen view of the far side of the star at the center of our universe. The composite image above was captured on June 1, 2011, <a href="http://www.nasa.gov/mission_pages/stereo/news/farside-060111.html" target="_hplink">and according to NASA</a>, "is the first complete image of the solar far side, the half of the sun invisible from Earth." <a href="http://www.huffingtonpost.com/2011/02/07/nasa-stereo-sun-images-video_n_819510.html" target="_hplink">Click here for more</a> on the STEREO probes.

  • Messenger Reaches Mercury

    While it's not a "discovery," <em>per se</em>, it's a milestone that will no doubt lead to many new findings about the smallest and innermost planet in our solar system. In March, after a 6 1/2-year, 4.9 billion mile journey, <a href="http://www.huffingtonpost.com/2011/03/18/nasa-messenger-mercury_n_837503.html" target="_hplink">NASA's Messenger spacecraft reached Mercury's orbit</a>. Messenger, the first spacecraft to orbit Mercury, <a href="http://messenger.jhuapl.edu/mer_orbit.html" target="_hplink">orbits the planet</a> every 12 hours. In November, <a href="http://www.nasa.gov/mission_pages/messenger/media/MissionExtends.html" target="_hplink">NASA announced that the spacecraft's mission</a>, which was supposed to end on March 17, 2012, would be extended for an additional year.

  • Pluto's Tiny Moon

    In July, NASA said that its Hubble Space Telescope <a href="http://www.huffingtonpost.com/2011/07/20/new-pluto-moon-hubble-space-telescope_n_904578.html" target="_hplink">discovered an eight to 21-mile-wide moon</a> circling the dwarf planet.

  • Black Hole Eats A Star

    In March, <a href="http://www.huffingtonpost.com/2011/04/07/nasa-cosmic-blast_n_846333.html" target="_hplink">NASA's Swift satellite saw an unusually long explosion of gamma-rays</a>. After studying the X-rays, <a href="http://www.huffingtonpost.com/2011/08/25/black-hole-eats-star-video_n_937150.html" target="_hplink">scientists found that they came from</a> a black hole that had become reenergized when it devoured a star. <a href="http://www.nasa.gov/home/hqnews/2011/aug/HQ_11-271_Swift_Black_Hole.html" target="_hplink">From NASA</a>: <blockquote>Astronomers soon realized the source, known as Swift J1644+57, was the result of a truly extraordinary event -- the awakening of a distant galaxy's dormant black hole as it shredded and consumed a star. The galaxy is so far away, it took the light from the event approximately 3.9 billion years to reach Earth. </blockquote>

  • Huge Mountain Discovered On Asteroid

    <a href="http://www.nasa.gov/mission_pages/dawn/main/index.html" target="_hplink">NASA's Dawn</a>, an ion-propelled spacecraft that traveled 1.7 billion miles before reaching the asteroid Vesta in July, sent back images in October revealing that <a href="http://www.huffingtonpost.com/2011/10/05/vesta-mountain-dawn-nasa_n_996282.html" target="_hplink">Vesta is home to a mountain larger than any mountain</a> on Earth. In December, NASA released new images that Dawn took when it was orbiting only 130 miles above the asteroid, the closest it will get to Vesta. Dawn will continue to image Vesta until next summer, when it will make its way to Ceres, a bigger asteroid.

  • 'Star Wars'-Like Planet

    <a href="http://www.huffingtonpost.com/2011/09/15/kepler-16b-planet-two-suns_n_964799.html" target="_hplink">NASA's Kepler spacecraft found a planet</a> that orbits two suns, driving fans of the "Star Wars" franchise <a href="http://blog.moviefone.com/2011/09/16/astronomers-discover-real-life-tatooine-star-wars/" target="_hplink">to call it a real-life Tatooine</a>. Astronomers announced Kepler-16b, which is the first circumbinary planet -- meaning it orbits two stars -- in September. <a href="http://www.huffingtonpost.com/2011/09/15/kepler-16b-planet-two-suns_n_964799.html" target="_hplink">Click here for more</a> on Kepler-16b.

  • 'Habitable Zone' Planet Found

    Scientists in early December <a href="http://www.huffingtonpost.com/2011/12/05/kepler-22b-new-planet-discovered-habitable-zone_n_1129591.html" target="_hplink">announced the discovery of Kepler-22b</a>, a planet with a temperature of around 72 degrees that's in the so-called <a href="http://en.wikipedia.org/wiki/Habitable_zone" target="_hplink">"Goldilocks," or habitable zone</a>. While the temperature of the 600-light-year away planet could sustain water, it has a radius of 2.4 times that of Earth's, so <a href="http://www.huffingtonpost.com/huff-wires/20111206/us-sci-alien-planet/" target="_hplink">it's probably too big</a> to harbor life.

  • Biggest Black Holes Ever Discovered

    Astronomers announced in early December that <a href="http://www.huffingtonpost.com/2011/12/05/black-hole-scientists-discover-huge_n_1129727.html" target="_hplink">they had found the biggest black holes to date</a>. The massive black holes, which are 10 billion times the size of the sun, are located over 300 million light years away.

  • Europa's 'Great Lakes'

    Scientists had long-thought that a large body of water existed under the surface of Europa, Jupiter's moon, but it was thought to be tens of miles below an icy crust. In November, though, astronomers analyzing data from <a href="http://solarsystem.nasa.gov/galileo/" target="_hplink">NASA's Galileo spacecraft</a> found evidence that suggests blocks of ice interact with water below the surface, which could mean that nutrients and energy are moving between the underground ocean and icy shell. <a href="http://www.ig.utexas.edu/people/staff/britneys/" target="_hplink">Britney Schmidt</a>, the lead author of the study, <a href="http://www.nature.com/nature/journal/v479/n7374/full/nature10608.html" target="_hplink">which appeared in the journal Nature</a>, said that the interaction "could make Europa and its ocean more habitable for life." <a href="http://www.huffingtonpost.com/2011/11/17/europa-water-jupiter-moon-photo-video_n_1099463.html#s480278&title=Europa" target="_hplink">Click here to read more</a> about water on Europa.

  • 'Bubbles' At The Edge Of Solar System

    NASA's Voyager probes -- launched over 30 years ago -- found huge magnetic "bubbles" at the edge of the solar system. "The sun's magnetic field extends all the way to the edge of the solar system," astronomer Merav Opher of Boston University <a href="http://www.nasa.gov/mission_pages/voyager/heliosphere-surprise.html" target="_hplink">said in a NASA statement</a>. "Because the sun spins, its magnetic field becomes twisted and wrinkled, a bit like a ballerina's skirt. Far, far away from the sun, where the Voyagers are, the folds of the skirt bunch up." Voyager 1 and Voyager 2 were launched in 1977. Voyager 1 is currently 11 billion miles away and may exit our solar system within the next few years.

  • Gypsum On Mars

    In December, scientists announced that NASA's <a href="http://www.huffingtonpost.com/2011/12/08/mars-water-opportunity-rover-gypsum_n_1136483.html" target="_hplink">Mars Rover Opportunity may have found gypsum </a>that had been deposited by water. "This tells a slam-dunk story that water flowed through underground fractures in the rock," <a href="http://astro.cornell.edu/people/facstaff-detail.php?pers_id=112" target="_hplink">Steve Squyres</a>, a planetary scientist at Cornell University and the principal investigator for Opportunity <a href="http://www.nasa.gov/mission_pages/mer/news/mer20111207.html" target="_hplink">said in a NASA statement</a>. NASA's Curiosity Rover <a href="http://www.huffingtonpost.com/2011/11/26/nasa-mars-curiosity-launc_n_1113995.html" target="_hplink">is en route to the Red Planet</a> and will arrive in August 2012.

  • Earth-Size Planets Discovered

    Weeks after <a href="http://www.huffingtonpost.com/2011/12/05/kepler-22b-new-planet-discovered-habitable-zone_n_1129591.html" target="_hplink">the announcement of Kepler-22b</a>, scientists said that <a href="http://www.huffingtonpost.com/2011/12/20/new-planets-kepler-exoplanets_n_1161213.html" target="_hplink">they'd discovered Kepler-20e and Kepler-20f</a>, two planets that are about the size of Earth. While the planets are too close to their sun-like star to harbor life as we know it, the discovery proved that the Kepler spacecraft was capable of spotting planets that are Earth-size, and brings us one step closer to finding a true Earth twin. <a href="http://www.huffingtonpost.com/2011/12/20/new-planets-kepler-exoplanets_n_1161213.html" target="_hplink">Click here for more</a> on the new planets.

  • Charles Camarda: NASA Innovation