Workshop: Not enough room for the universe

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By Roger Snodgrass

SANTA FE – The universe, in all its scales, frequencies, bits and chunks, is becoming too numerous for astronomers to handle.

The Great Survey Workshop this weekend in Santa Fe brought about 75 astronomers together to compare datasets and share algorithms about the vast new wave of information that is flooding in from the cosmos.

“There is a sea change in the way people are doing astronomy,” said Salman Habib, speaking of the trend in astronomy to try to study large number of objects. Habib is a Los Alamos National Laboratory astrophysicist and as leader of the Astrophysics and Astronomy Center, was one of the organizers of the conference

“If you look at only one or two objects in the universe, you don’t know what’s interesting,” he said. The tendency now is toward large collections, epitomized by the Sloan Digital Sky Survey, which is based in southern New Mexico and now in its third evolution.

But the information revolution in turn is putting more strain on the many aspects of gathering, selecting, analyzing, comparing, storing and getting the correct information into the right hands at the right time, some of the hot topics at the workshop.

Tom Vestrand, who heads RAPTOR (RAPid Telescopes for Optical Response,) the nimble robotic telescope system at LANL’s Fenton Hill observatory, amplified the theme during a 20-minute presentation Friday afternoon.

“We have reached the tipping point,” he said. During normal operations, the Raptor generates hundreds of petabytes, hundreds of thousands of trillions of bytes an hour.

Among the billions of persistent objects in a field of observation, he asked, how do we mange to find the one meaningful “bump in the night.” One such bump that RAPTOR pinpointed in March 2008 was a Gamma Ray Burst that turned out to be the most luminous object every detected by humankind

Until recently, astonomers relied on luck a lot. When luck failed, they resolved to catch something missed the next time around by tweaking their instrument, or using a triage approach to optimize and focus their searches.

The RAPTOR project, Vestrand said has to have an aspect of machine learning, comparable to the credit card, that sets off an alert in the appropriate context, but doesn’t prevent the wealthy customer from buying the seven Rolex watches that would not be out of character.

Finding and classifying rare and anomalous objects, white-dwarf binaries or quasars, or Active Galactic Nuclei, require more mountains of storage and computing power, as other speakers from Princeton, British Columbia, China and Australia said as well.

Large astronomical surveys have been around for a few hundred years.

One of the earliest and most influential was the catalogue of French astronomer Charles Messier, a comet hunter from childhood, who began in 1757 to create a list of fuzzy objects in the heavens that he did not want to mistake for comets.

He called them nebulae, and they turned out to be galaxies and star clusters that foretold a much deeper universe than was thought to exist.

The first object in his catalogue was what would later be called the Crab nebula, the remnant of the supernova of 1054, an astronomical event that was recorded around the world.

A survey at Lawrence Berkeley National Laboratory a decade ago, the Supernova Cosmology Project, first announced the discovery of dark energy, a mysterious and dominant form of energy responsible for the accelerating expansion of the universe.

Dark energy appears to be one of the driving forces behind the large astronomical survey projects that are waiting in the wings to begin.

Plans were formalized this week between NASA and the DOE for the Joint Dark Energy Mission, a space-based observatory focused on understanding this bafflingly mysterious stuff that comprises 70 percent of the total mass energy of the universe, yet is virtually inexplicable.

“We have no nice way to think about it,” said Habib, calling dark energy a fundamental challenge to physics.  “That’s why we want to poke it and learn from it,” he said.

Habib is one of the principal investigators on the Roadrunner Universe project, proposed to carry out the largest high-resolution simulations of the distribution of matter in the universe, a map that is intended to guide Dark Universe science for years to come.

The Great Surveys Workshop and the Astrophysics and Cosmology Center

are sponsored by the LANL Institute for Advanced Studies.

The wide, fast and deep Large Synoptic Survey Telescope under development in Chile and the Square Kilometer Array radio telescope to be located in either Western Australia or South Africa are examples of other future large survey programs coming on line in the next decades that were discussed at the conference.