NASA / D.Berry
An illustration of a gamma-ray burst, the most powerful explosion type yet seen in the universe.
updated 12/8/2012 10:04:01 AM ET 2012-12-08T15:04:01

Light from some of the universe's most energetic explosions is allowing scientists to probe the nature of space-time, according to new observations of so-called gamma-ray bursts from the Japanese Aerospace Exploration Agency's Ikaros spacecraft. Photons released by these bursts help place limits on a unified model of all of the forces of nature — what scientists call a "theory of everything."

  1. Space news from
    1. KARE
      Teen's space mission fueled by social media

      Science editor Alan Boyle's blog: "Astronaut Abby" is at the controls of a social-media machine that is launching the 15-year-old from Minnesota to Kazakhstan this month for the liftoff of the International Space Station's next crew.

    2. Buzz Aldrin's vision for journey to Mars
    3. Giant black hole may be cooking up meals
    4. Watch a 'ring of fire' solar eclipse online

Using the Gamma-Ray Burst Polarimeter (GAP) onboard the spacecraft, a team of Japanese scientists have made the most precise measurements of energetic gamma-ray burst photons to date.

"This result puts a fundamental constraint on quantum gravity, a dream theory reconciling Einstein's theory of relativity and quantum theory," Kenji Toma, of Osaka University, said in a statement.

A quantum universe
Gamma-ray bursts are exceptioinally powerful explosions thought to result from violent events like star deaths and collisions of dense neutron stars. Toma and his team used detailed measurements of gamma-ray bursts to study the properties of the photons and determine their polarization, or how their electric fields are oriented in relation to the motion of the particles. The electric field of polarized light bounces up and down on an axis perpendicular to the direction the photons travel in.

[ 5 Reasons We May Live in a Multiverse ]

"Most 3D projection systems in movie theaters project two versions of the movie at two different polarizations — both at 45 degrees to the horizontal, but perpendicular to each other — so that when you view the movie through appropriately polarized glasses, the left eye sees the version of the movie meant for the left eye, and the right eye sees the version meant for the right," astrophysicist Derek Fox of the University of Pennsylvania told by email. Fox was not part of the team behind these findings, but studies gamma-ray bursts like those observed in this case.

The findings could have implications for superstring theory — the idea that all fundamental particles are actually loops of vibrating string — which is one attempt to unify nature's forces and create a theory of everything. If the idea is right, it would help reconcile two contradictory theories: Einstein's general relativity, which describes things that are very big, like gravity, and quantum mechanics, which describes the realm of the very small.

"We live in a quantum universe — quantum mechanics is needed to describe the behavior of all forces and all particles at the subatomic level," Fox said. "Ultimately, we can hope to develop a 'quantum gravity' theory of these phenomena."

Violating symmetry
Superstring theory scientists predict that if particles and anti-particles (antimatter is an opposite form of normal matter) traded places and time was reversed, the world would still look the same. If any evidence is uncovered that matter and antimatter actually act differently, or violate their apparent symmetry, it could offer support for superstring theory.

"If it were proven to be violated by any physical process, even at some tiny level, then this would radically change the direction of current theoretical approaches to constructing a unified model of all the forces of nature," Fox said.

Collecting observational evidence can prove challenging, as many quantum structures are too small to probe with present-day technology on Earth, making a space-based probe a necessity.

Photons streaming from gamma-ray bursts have thus far shown no changes in the rotation of their polarity. Such a rotation would indicate a lack of symmetry if time were reversed and particles and anti-particles switched.

Studying three gamma-ray bursts with significantly more precision than ever before, Toma and his team found no change in the polarization of the photons, implying that the symmetry is consistent to at least one part in 10 million. This is a new record in constraining the rules that govern nature, and will influence attempts to create a unified theory.

The research will be published in an upcoming issue of the journal Physical Review Letters.

A powerful source
Gamma-ray bursts are brief spikes that can last from a few seconds to a few minutes. The light from them can travel billions of light-years in the form of streaming high-energy photons that are unable to penetrate Earth's atmosphere.

Emitting as much energy in a few seconds as the sun does in a lifetime, the explosions may come from flare-ups during the formation of a neutron star or black hole — two possible outcomes of star deaths — or the sudden collision of neutron stars. The powerful forces involved in such events accelerate photons almost to the speed of light.

"Gamma-ray bursts have relatively high energies — compared to, say, radio or optical photons — which make them useful probes of the possible quantum structure of space-time," Fox said. He went on to call them "a natural choice as target sources for these tests."

Launched in May 2010, Ikaros is the first spacecraft outfitted with a solar sail. GAP is positioned at the probe's back end, pointing away from the sun and into deep space.

Follow on Twitter @Spacedotcom. We're also on Facebookand Google+

© 2013 All rights reserved. More from

Photos: Month in Space: January 2014

loading photos...
  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
  1. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  2. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  3. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.

  4. Editor's note:
    This image contains graphic content that some viewers may find disturbing.

    Click to view the image, or use the buttons above to navigate away.


Discussion comments


Most active discussions

  1. votes comments
  2. votes comments
  3. votes comments
  4. votes comments