A public call to help a team of scientists from the United
States and Britain
classify nearly a million galaxies has been nothing short
of a cosmic
phenomenon.
On July 11, a group of researchers and faculty from
Johns Hopkins, the
University of Oxford and the University of Portsmouth went
live with its Galaxy
Zoo project, a Web site that gives armchair astronomers
access to stunning
images of the cosmos, most of which have never been seen
before. In essence, the
scientists sought to enlist an army of volunteers from
around the world to help
complete a massive galaxy census.
To date, the site has recorded nearly 56.5 million
hits, attracted 75,000
registered users, been the featured site on Wikipedia.org
and even inspired a
blog and a poem.
No telescope needed for this astronomical endeavor;
Galaxy Zoo requires
just a computer and an Internet connection. After a short
tutorial and required
test, participants are shown a random galaxy image,
courtesy of the Sloan
Digital Sky Survey telescope in New Mexico. The volunteers
are then asked to
identify the image as a spiral galaxy (clockwise,
counterclockwise or edge-on),
elliptical galaxy, a merger of galaxies or a star. Users
can classify as many
galaxies as they like. One unidentified volunteer has
classified more than
10,000 images.
More than 8 million classifications have been
submitted so far for the
900,000-plus galaxies in the Galaxy Zoo, which is just a
small slice of the
Sloan data set.
Though the process is not a perfect science, the more
volunteers the
astronomers get, the more accurate the results, said Johns
Hopkins' Alexander
Szalay, Centennial Professor of Astronomy in the
Henry A. Rowland
Department of
Physics and Astronomy and an architect of the Sloan
database.
"We hoped that for every galaxy we'd receive a large
number of identical
classifications so that we could, with high confidence,
determine its shape,"
said Szalay, who noted that the human brain is actually
better than a computer
at pattern recognition.
Astronomers hope the project's results will help them
better understand
the structure of the universe and how galaxies form and
evolve. Does one galaxy
type evolve into another? In theoretical simulations,
astronomers have found
that the merger of spirals can create an elliptical, and
that an elliptical can
become a spiral by accretion of further stars and gas
during its lifetime.
The information gathered could also be used to help
develop galaxy
classification software that can be applied to much larger
datasets.
"I think scientists will find our results very useful,
and the data can be
used for a number of science projects," said Szalay, a
professor of computer
science.
The Galaxy Zoo team has been overwhelmed by the
response, he said, as have
the JHU-hosted computer servers.
"This has far exceeded our expectations," he said. "In
a way, we didn't
know what to expect. You take the time to build a site like
this, but you're
thinking it could be a total flop and nobody will come.
Yet, on the firstday,
we had 1 million hits. Amazing."
A few hits too many, actually, as the Web site's
servers slightly buckled
under the strain, causing some initial delays in response
and computer timeouts.
The crushing site traffic even blew a circuit in the data
center, according to
Jan Vandenberg, computer systems administrator in the
Physics and Astronomy
Department.
"We've had a lot of big site rollouts and faced some
serious traffic
before, but this was the biggest yet," Vandenberg said.
"Nobody imagined that
something so seemingly mundane as classifying galaxies
would become such a fan
pastime."
According to some Galaxy Zoo bloggers, the
classification process is
downright addictive and you can't stop at one. As a
reminder of their visit,
participants are able to print out posters of the galaxies
they have explored.
The project's concept originated with Kevin
Schawinski, an astrophysicist
at Oxford University, and Chris Lintott, a postdoctoral
researcher at Oxford and
the co-host of the popular BBC show The Sky at Night. The
pair quickly won the
support of Sir Patrick Moore, the famous British astronomer
and longtime host of
The Sky at Night, and Brian May, the lead guitarist of the
rock band Queen and
the co-author, with Lintott and Moore, of the book Bang!
The Complete History of
the Universe. May, who recently completed his thesis for a
PhD in astronomy,
brought in a graphic designer who created the project's
site.
Schawinski himself had classified thousands of
galaxies taken from SDDS, a
massive project to survey and map one-quarter of the entire
sky in detail, but
quickly realized it was too big a job for one man. So, he
decided to spread the
fun around.
To join in, go to
www.galaxyzoo.org.