Communications - May 2010

than five million SETI@home volunteers, essentially constitutes one of the world’s largest supercomputers, and is an excellent example of how a network of home computers can be amazingly efficient by spreading around the processing burden.

Another ongoing citizen science program, Galaxy Zoo, uses tens of thousands of home computers, but in this case the processing power lies mostly in the human brain. Originally launched in 2007, Galaxy Zoo is the most massive galaxy classification project ever undertaken. Galaxies come in a mind-boggling variety of shapes and combinations, making classifying them extremely difficult. Galaxy Zoo was tasked with classifying the nearly one million galaxies swept up in the Sloan Digital Sky Survey, the most ambitious survey in the history of astronomy. Computers and the Internet have been instrumental in circulating images of galaxies to thousands of volunteers, but the success of Galaxy Zoo depends on the pattern recognition faculties particular to humans.

“Supercomputers, or even my bat-
tered old laptop, can beat large num-
bers of humans for sheer processing
power,” says Chris Lintott, an astro-
physicist at Oxford University. “The
problem we were facing is one of pat-
tern recognition, and for this task, we
humans have a huge advantage.”
Computerized methods of galaxy
classification have been applied to gal-
axy surveys before, including the Sloan
Digital Sky Survey, but their galaxy clas-
sification is correct about only 80% of
the time, says Lintott. “That may not
sound too bad, but the missing 20%
are often those that are unusual and
thus contain the most information,”
he says. As Galaxy Zoo team members
have discovered, humans are adept at
spotting unusual details. For example,
volunteers noticed some small, round
green objects, now known as “peas,”
in the background of some Galaxy Zoo
images. “They turn out to be the sites of
the most efficient star formation in the
present-day universe, but it was only be-
cause our volunteers spotted them that
we knew to study them,” says Lintott.

A new incarnation of the project, Galaxy Zoo 2, is now under way and includes a supernova search adjunct. A veritable flood of data is expected. “In

“exoplanets are
greatly expanding
the planetary
menagerie,” says
Bruce fegley, Jr.
“they provide us
with all sorts of
oddball planets
that one could only
imagine in the past.”

the long run, I think we’ll need a combination of man and machine,” says Lintott. “This sort of development is going to be necessary to cope with the next generation of sky surveys, which should produce data rates of up to 30 terabytes per night.”

Information;Retrieval

Data
Deluge

The U.s. Blue ribbon Task Force on sustainable digital Preservation and access released its final report,

Sustainable Economics for a Digital Planet: Ensuring Long-term Access to Digital Information, a two-year effort that addressed the economic challenges of preserving the world’s ever-increasing amount of digital information.

“The data deluge is
here,” said Fran Berman,
vice president for research
at rensselaer Polytechnic
institute and co-chair of the
task force. “ensuring that our
most valuable information
is available both today and
tomorrow is not just a matter
of finding sufficient funds. it’s
about creating a ‘data economy’
in which those who care,
those who will pay, and those
who preserve are working in
coordination.”
The Sustainable Economies
report focuses on the
economic aspects of digital
data preservation, such as how
stewards of valuable, digitally
based information can pay for
preservation over the longer
term. The report provides
principles and actions to
support long-term economic
sustainability; context-specific
recommendations tailored to
specific scenarios analyzed in
the report; and an agenda for
priority actions and next steps.

The report also concentrates on four different scenarios, each having ever-increasing amounts of preservation-worthy digital assets in which there is a public interest in long-term preservation: scholarly discourse, research data, commercially owned cultural content, such as digital movies and music, and collectively produced Web content, such as blogs.