Our Universe: Dark and Messy

Ouruniverse is a mess — a colossal "cosmic web" of galaxies strung intofilaments and tendrils that are millions or billions of light-years long.

Althoughthis web's basic structure is resolved, astronomers say understanding it inmore detail requires new observatories, better computing and a lot of luck.

"Whenyou look into a large telescope, the reality of thecosmic web hits you in the face because you can see how galaxies areorganized," said Rodrigo Ibata, an astronomer at the Observatoire Astronomiquede Strasbourg in France. "We have clear evidence for the cosmic web'sexistence, but there is still so much we don't know about it."

Ibataexplained that the cosmic web filaments are held together bydark matter, unseen stuff that makes up 85 percent of all mass in theuniverse.

"It'sintrinsically tough to study something you can't see, so dark matter makesunderstanding the cosmic web an exceedingly difficult challenge," Ibatatold SPACE.com.

Ibata andother astronomers detail some of the cosmic web's mysteries last week in thejournal Science.

Intergalactichighway

The cosmicweb is thought to funnel galaxies, gas anddark matter around the universe, something like a chaotic intergalactichighway. Ibata said he's looking to our own celestial neighborhood for effectsof this network.

"Wethink cosmic web tendrils feed directly into galaxies, dump matter onto themand build them up," Ibata said.

Ibata hopesnew star data gathered by the European Space Agency's GAIA spacecraft, set tolaunch in 2011, will help gather evidence of such activity near the Milky Way.

"It'sgoing to make things very interesting over the coming years," he said ofGAIA, which will finely measure the distances and movements of more than abillion local stars. Such data could reveal where — and what — cosmic webtendrils might be spilling into our neck of the celestial woods.

"Theenvironment within these tendrils could be one of the most important factors ingalaxy formation," Ibata said.

To use mountainsof data that GAIA and other observatories are expected to deliver in thefuture, however, Ibata said computer technology will have to catch up. "Ifwe were to get such data now, we wouldn't be able to efficiently processit," he said.

Simulatingthe universe

Claude-AndreFaucher-Giguere, a graduate student in astrophysics at Harvard University, agrees.

"Weneed powerful computers to deal with raw astronomy data," Faucher-Gigueresaid. "But another aspect is that once it's processed, we need to be ableto learn something from it."

Faucher-Gigueresaid computer simulations help with the task by giving astronomers grounds forcomparison. If a simulation fits a set of observations, it helps astronomerspick the best theoretical track to explain what they see.

Our currentbig-picture view of the universe is based mostly on optical light,Faucher-Giguere said, but newobservatories will look deep into the cosmos in wavelengths such asinfrared and radio.

"We'llneed new, better simulations to make sense of data we haven't yet learned howto analyze," he said. "We need to be prepared or else we won't knowwhat we're looking at."

Faucher-Giguereexpects astronomers to increasingly team up with computer-savvy theoreticiansto extract the latest knowledge about our universe in an efficient way.

"Astronomyis driven by new observations," he said, "but to make use of thesenew windows onto the universe, we really have to keep up with the theoreticalwork."

Have a news tip, correction or comment? Let us know at community@space.com.