article from the economist

[hilda]

I'd sent this particle from the economist to Richie and Chris: it made
me dream about sswl!
Chis asked me to post it to the group, so here it is. Enjoy!
Hilda.
________________
STARS IN THEIR EYES
Jun 26th 2008


An armchair astronomer discovers something very odd

THE task of peering into the cosmos and discovering strange new
galaxies sounds like a job for astronomers armed with big and very
expensive telescopes. But almost a year ago that all changed when a
group of stargazers decided to ask the public to help in a project to
explore the northern sky.

The Sloan Digital Sky Survey had been looking in this part of space
for
16 years, producing so much information that astronomers assumed they
would never get through it. So the public was let loose, to help sort
what they had found. The scheme is called the Galaxy Zoo project.

It was so popular, says Alex Szalay, an astronomer at John Hopkins
University, Maryland, that the computer servers on which the project
ran "literally overheated and blew a fuse". More important, within a
month of the opening, Hanny van Arkel, a physics teacher from the
Netherlands, posted a message on the zoo's forum about some strange
blue stuff she had spotted and asked what it might be.

By January the zoo's professional keepers had started to pay attention
to what the teacher had called a VOORWERP, the Dutch word for object.
Now it is becoming famous. William Keel, an astronomer at the
University of Alabama, took another picture of the VOORWERP and
suggested that the human eye would probably see it as green, rather
than blue as in the original picture. It also has a giant hole at its
centre.

What this object might be was a complete mystery at first. It was
initially thought to be a distant galaxy, says Chris Lintott, an
Oxford
University astronomer involved in the project. But after further study
astronomers realised that there were no stars in it, and so it must be
a cloud of gas. But why the gas was so hot (about 15,000ºC) was a
mystery, because there seemed to be no stars to heat it up.

Now, in a posting on the Galaxy Zoo blog[1], Dr Keel and Dr Lintott
suggest that the galaxy right next door to the VOORWERP used to be a
quasar (a very bright active galactic nucleus) that has since eaten up
all its fuel. This quasar lit up the nearby gas, and although the
quasar has since gone out, the light from it is still travelling to
the
object. The blob, says Dr Lintott, sees the galaxy as it was 40,000
years ago. This makes the VOORWERP a sort of light echo but on a
massive scale. Smaller light echoes have been seen around supernovae.
As for the giant hole, Dr Lintott has "no sensible explanation" for
that at the moment and needs to wait for more telescope time.

The weird blob could become immortalised as Hanny's Voorwerp, the name
given to the object in a paper Dr Lintott and his colleagues are
submitting to the MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY.
And towards the end of the year, if the mission to service the Hubble
telescope goes as planned, a high-quality image of the VOORWERP could
emerge.

DATA DIRECT
Earlier projects in distributed computing, such as SETI@home[2], which
searched for extraterrestrial life, have used the power of millions of
home computers. But more recently, scientists have begun to realise
that distributed human brain power itself can be a useful commodity,
as
in working out the shape of proteins. Dr Szalay says that the VOORWERP
episode has shown how immensely valuable the public can be.

When the data were put online Dr Szalay thought it was only a matter
of
time before someone made a big discovery. "It just happened much
faster
than we thought." In the past year 40m classifications of galaxies
have
been submitted on 1m galactic objects in the Galaxy Zoo. Dr Lintott
says that the project has proved that the public EN MASSE is as good
as
professional astronomers at classifying galaxies.

The next step is to ask people to do more complicated things, such as
keeping an eye out for weird objects, which is bound to appeal to
armchair astronomers. Hanny's object had been there for decades,
unnoticed in the astronomical archives. The idea now is for the public
to explore strange new galaxies; to seek out new VOORWERPS and to
boldly go where no amateur has gone before.

-----
[1] http://www.galaxyzooblog.org/
[2] http://setiathome.berkeley.edu/



See this article with graphics and related items at
http://www.economist.com/science/displaystory.cfm?story_id=11614176

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