After
overcoming a glitch that had forced science operations to cease, operators
wasted no time in using the Hubble Space Telescope to photograph another
stunning cosmic scene.
The
new image, released today, shows an odd pair of galaxies called Arp 147.
In
the image, a galaxy at left looks somewhat like the number "1" and is
relatively undisturbed, but for a smooth ring of starlight. It appears nearly
edge-on to our line of sight. A galaxy at right, looking like a
"zero," exhibits a clumpy, blue ring of intense star formation.
Mission
officials suggested the image is a perfect "10." It shows that
the observatory's Wide Field Planetary Camera 2 (WFPC2) is working exactly as
it did before going offline.
The
blue ring was formed after the galaxy on the left passed through the galaxy on
the right. Just as a pebble thrown into a pond creates an outwardly moving
circular wave, or ripples, an outwardly propagating ring of higher density was
generated at the point of impact of the two galaxies, astronomers explained. As
this excess density collided with outer material that was moving inwards due to
the gravitational pull of the two galaxies, shocks and dense gas were produced,
stimulating star formation.
The
dusty reddish knot at the lower left of the blue ring probably marks the
location of the original nucleus of the galaxy that was hit.
Arp
147 appears in the Arp Atlas of Peculiar Galaxies, compiled by Halton Arp in
the 1960s and published in 1966.
Arp
147 lies in the constellation of Cetus, more than 400 million light-years from
Earth.
Bouncing
back
The Sept.
27 failure of a vital data relay channel left the 18-year-old Hubble telescope unable to
transmit the bulk of its science data and imagery. The channel, the Side A
relay of Hubble's Science Instrument Control and Data Handling system, had been
working properly since the telescope launched in April 1990.
Efforts to
switch to a backup Side B channel last week met with challenges
of their own, with two separate glitches thwarting the initial attempt. But
a second try appears to have been successful, with Hubble engineers
reactivating the telescope's main science instruments over the last week.
The remote
control fix required engineers to power up and switch to backup systems that
had been hibernating since Hubble launched into space.
Hubble's
September data relay channel failure prompted NASA to delay a planned Oct. 14
space shuttle launch to send seven astronauts to the orbital observatory on a fifth
and final service call to the telescope. That mission is now slated to fly
no earlier than February, with Hubble engineers testing a spare data relay
channel to see if it can be added to the shuttle's cargo bay and be installed
during the flight.
Hubble
officials are expected to give an update today at 5:00 p.m. EDT (2000 GMT) on
plans for the servicing mission. The service call is expected to include five
spacewalks to add a new camera, upgrade guidance equipment, replace aging batteries
and gyroscopes, deliver a docking ring and include repairs for systems never
designed to be repaired in space.
The final
Hubble overhaul is expected to extend the space telescope's mission lifetime
through at least 2013, mission managers have said.
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