Image: Dark matter distribution
Van Waerbeke, Heymans, CFHTLenS Collaboration
Recent observations show that dark matter in the universe is distributed as a network of gigantic dense (white) and empty (dark) regions, where the largest white regions are about the size of Earth's moon on the sky.
updated 1/9/2012 11:37:42 AM ET 2012-01-09T16:37:42

Astronomers have created a vast cosmic map revealing an intricate web of dark matter and galaxies spanning a distance of 1 billion light-years.

This unprecedented task was achieved not by observing dark matter directly, but by observing its gravitational effects on ancient light traveling from galaxies that existed when the universe was half the age it is now.

Constructed by astronomers from the University of British Columbia and University of Edinburgh, this is the largest dark matter map ever built and took five years to complete.

The research was presented at the American Astronomical Society meeting in Austin, Texas, on Monday.

ANALYSIS: Mapping dark matter with a cosmic lens

Dark matter pervades the entire observable universe, accounting for 83 percent of the mass of the cosmos. But as it does not scatter or radiate light (or any kind of electromagnetic radiation for that matter), we cannot see it. Naturally, this poses an interesting problem for astronomers hoping to map the stuff.

However, astronomers can indirectly observe dark matter as its mass exerts a gravitational force on the space-time surrounding it. As light travels from distant galaxies, it will be bent around gravitational distortions in space-time — much like the paths of marbles rolling across a bent sheet of plastic — being caused by the dense regions of dark matter.


With this in mind, the international team of astronomers analyzed light from 10 million galaxies in four regions of the sky — all of which are about 6 billion light-years from Earth. As these galaxies are 6 billion light-years away, it took the light 6 billion years to travel that distance.

ANALYSIS: Dark matter mystery unraveled by dwarf galaxies?

Using a 340 Megapixel camera called "MegaCam" attached to the Canada-France-Hawaii Telescope (CFHT) in Hawaii, the ancient galactic light was analyzed to reveal the distorted paths each source traveled, thereby revealing the gravitational terrain surrounding clouds of dark matter.

  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

"It is fascinating to be able to 'see' the dark matter using space-time distortion," said Ludovic Van Waerbeke of the University of British Columbia.

WATCH VIDEO: What about dark energy?

"It gives us privileged access to this mysterious mass in the universe which cannot be observed otherwise."

Catherine Heymans of the University of Edinburgh's School of Physics and Astronomy added: "By analyzing light from the distant universe, we can learn about what it has traveled through on its journey to reach us. We hope that by mapping more dark matter than has been studied before, we are a step closer to understanding this material and its relationship with the galaxies in our Universe."

Both Heymans and Van Waerbeke lead the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS) team.

ANALYSIS: How low can a dark matter halo go?

It is now hoped that other observatories — such as the Very Large Telescope's (VLT) Survey Telescope in Chile — will build on the CFHTLenS feat and create an even bigger dark matter map.

"Over the next three years we will image more than 10 times the area mapped by CFHTLenS, bringing us ever closer to our goal of understanding the mysterious dark side of the universe," said Koen Kuijken of Leiden University.

Understanding the nature of dark matter is critical to our knowledge of how the Universe evolved to form planets, stars and galaxies. Mapping this vast — yet invisible — cosmic web is a big step in that direction.

© 2012 Discovery Channel

Interactive: Why does dark matter matter?

Explainer: Dark matter revealed

  • ESA

    Step right up and click inside to see dark matter revealed! Scientists think the mysterious substance makes up most of the mass in the universe — but because it doesn't give off light, visible proof of its existence is elusive. Theory suggests that the invisible stuff acts as gravitational glue that keeps the stars and galaxies from flying apart. Now, armed with powerful telescopes, tricky lenses and fast computers, scientists are at last bringing the evidence of dark matter to light.

    For example, in this image, the yellowish galaxy cluster in the middle serves as a gravitational lens that bends the light of even more distant galaxies. Those galaxies appear as distorted blue streaks surrounding the cluster. Scientists can analyze the distortions to determine how dark matter is distributed in the cluster.

    Click to see what else scientists have found out about dark matter.

    — John Roach, contributor

  • Super clumpy

    NASA / ESA

    Dark matter, it turns out, may be rather clumpy stuff. This image shows a galaxy supercluster -- a grouping of hundreds of interacting galaxies -- about 2.6 billion light years from Earth. The bright blue spots are the visible galaxies, superimposed over magenta-tinted clumps that represent a detailed map of dark matter. The map was created by inferring how the light from even more distant galaxies is bent as it passes through the gravitational field of the supercluster, which is called Abell 901/902. Astronomers found that the supercluster's galaxies lie within the clumps of dark matter, and the irregular shapes of the clumps match the distribution of the galaxies.

  • Invisible scaffolding

    Todd Marshall

    This 3-D map of the large-scale distribution of dark matter in the universe provides compelling evidence that the invisible stuff serves as the scaffolding upon which the stars and galaxies are hung. The map reveals a network of filaments that grow over time and intersect in massive structures at places where galaxy clusters are located. To make the map, astronomers used ground and space telescopes to determine the shape of half a million distant galaxies. This galactic light was bent and warped by the gravity of other galaxies as it traveled to the telescopes. By analyzing the shapes of these distant galaxies, astronomers were able infer the distribution of dark matter.

  • Bullet proof


    For proof that dark matter really exists, scientists turn to this image of a collision between two massive galaxy clusters that contains a bullet-shaped cloud of superheated gas. Theory suggests that during such a collision, a type of cosmic air resistance should slow down the hefty hot gas — but not the dark matter. That's what this image shows. The hot gas, pictured in red, is separated by the dark matter, pictured in blue. Scientists say the image serves as strong evidence that dark matter really does exist.

  • Train wreck

    Prof. Rodolfo Coria / Ap

    A massive collision of galaxy clusters about 3 billion years ago has proven to be a train wreck of sorts for dark matter theory. The prevailing theory suggests that the force of gravity should keep dark matter and galaxies together even during violent collisions, but that hot gas should lag behind due to the cosmic equivalent of air resistance. This image, however, shows the dark matter (blue) separated from most of the galaxies (yellow and orange). Scientists speculate that a gravitational slingshot effect may have separated the galaxies from the dark matter, or that the dark matter is interacting with some force other than gravity. Neither explanation fits well with existing theory. A third possibility is that the observations and calculations are off. Further research may yield an answer.

  • Ghostly ring

    Some rings signify marriage, others a Super Bowl victory. This one may signify that dark matter exists. Astronomers made this composite image of a ghostly ring of apparent dark matter (mapped in blue) around a cluster of galaxies about 5 billion light years away. Computer simulations of the ancient galactic collision that created the cluster provide clues to how the ring formed. During the smash-up, dark matter fell to the center of the combined cluster and then started to slosh back out toward the edges. But the pull of gravity caused the dark matter to slow and pile up like cars speeding into a traffic jam on the freeway.

  • Cold or warm?


    Assuming dark matter does exist, is it cold or warm? If some of the universe's earliest stars can be found, computer simulations suggest the issue could be resolved. Slow-moving particles of cold dark matter would have caused single, massive stars to form in isolation. Faster-moving particles of warm dark matter, in contrast, would have caused the stars of differing sizes to form on long, thin filaments of dark matter — as pictured here. Since small stars are long-lived, they may still be lurking in our universe. Scientists hope to find them with new telescopes.

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