For aging Hubble, basic questions about the universe

Thursday, May 06, 2004
By Deborah Zabarenko, Reuters

BALTIMORE - With the end in sight for the Hubble Space Telescope,
astronomers said Wednesday they are posing the most basic cosmic
questions to the orbiting observatory, including queries about
extraterrestrial life. 

"It's definitely race-the-clock," said John Tonry of the
University of Hawaii, who gathered with other scientists at the
Space Telescope Science Institute for a forum on what problems
Hubble should tackle in its final years.

"The questions that we're answering now with Hubble were never
even anticipated when it was conceived of ... As time goes by we
just keep coming up with more questions and they seem more
important," Tonry said.

One of these essential questions is whether there is intelligent
life on planets besides Earth, said Mario Livio of the
Baltimore-based telescope institute. Another is the examination
of a mysterious dark energy, which is thought to make up about
three-quarters of the energy in the universe.

Livio said Hubble was able to determine the chemical composition
of the atmospheres of some of these extraterrestrial planets and
could close in on how strong dark energy is and whether it is
permanent or changes over time.

The scientists said other fundamental issues that can use
Hubble's abilities include queries about how stars blow up in
explosions known as supernovas, how supermassive black
holes - monstrous matter-sucking drains in space - relate to the
galaxies that swirl around them, and how galaxies formed in the
furious spate of creation in the early universe.

Without a service call from space shuttle astronauts, Hubble's
capabilities are expected to erode in the next two or three years
as its stability gyroscopes fail and its batteries fade, making
targeted observation all but impossible.

Poignant Time for Hubble

NASA chief Sean O'Keefe decided in January to forgo a servicing
mission set for 2005 or 2006, deeming it too risky and not in
keeping with recommendations made after the fatal shuttle
Columbia disaster.

The remaining three shuttles have been grounded since Columbia's
break-up on Feb. 1, 2003 and are not expected to fly for another
year or so. When they do, their efforts will focus on finishing
the International Space Station.

"This is a particularly poignant time in the history of Hubble,"
said Steve Beckwith, the space telescope's director. He said that
without a servicing mission, scientists would make only "scant
progress" on the supernova question and the issue of the
composition of the atmospheres of planets outside our solar
system.

"If Hubble is serviced, then on the other hand the questions will
have very significant progress," Beckwith said.

Jay Gallagher of the University of Wisconsin-Madison stressed the
orbiting telescope's importance.

"It's become, I think, a key tool in the astronomer's tool kit,
and missing it means we miss a chance to get a complete picture
of what's going on," Gallagher said. "In observational science
like this, if you're missing a brick, the whole thing can come
down."

Hubble, which carries optical and ultraviolet instruments, was
launched in 1990 with a projected lifespan of 15 years; servicing
missions have repaired and upgraded it. NASA has nothing on the
drawing board to replace Hubble's instruments, but there are
currently orbiting telescopes that look at the cosmos through
X-rays and through infrared light.

Source: Reuters
  
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