If all goes well in the next two weeks the venerable Hubble Space Telescope willembark on a new era of exploration that may well blow our collective socks offall over again.
Witha new camera set to be installed by the crew of Space Shuttle Columbia,Hubble's improved vision, combined with the planned revival of a dead infraredcamera aboard the craft, will provide new insight into the secrets of some ofthe universe's most distant objects. It will also expand the orbitingtelescope's ability to study newborn solar systems closer to home, according toastronomers interviewed by SPACE.com.
Hubble will even have an outside chance to take the first picture of a planet outsideour solar system.
Planet hunting
The new device, about the size of an old-fashioned phone booth, is called theAdvanced Camera for Surveys (ACS). It will replace Hubble's Faint ObjectCamera. ACS actually contains three cameras. One will view wide patches of sky,another will zoom in on smaller regions, and a third blocks out visible lightto enhance detection of ultraviolet radiation.
While the ACS will peer into the deepest regions of space, among its most interestingtasks will be a search for possible planets around two of the closest knownstars, Alpha Centauri A and B. These stars, just 4.3 light-years away, orbiteach other in what's known as a binary configuration.
Alpha Centauri A, the larger of the two, is similar to our Sun, fueling speculationthat it could be home to planets like those in our solar system.
"It'sa long shot," said David Golimowski, a research scientist at Johns HopkinsUniversity, where the new camera was designed. "If all the planets alignjust right," he said half jokingly, "and if we have very good fortunein the telescope performance and also in the way we plan the observations,there is a possibility we could image a planet."
No planet beyond our solar system has ever been photographed. Instead, duringroughly seven years of extrasolar planet discovery, astronomers have relied onindirect detection methods to find several dozen worlds around other stars.
Golimowski and his colleagues plan to hunt for a planet roughly the size of Jupiter. Ifone exists, it would be about a billion times fainter than its host star.
In order to see such a dim object in all that glare, the ACS is equipped with adevice called a coronagraph, which blocks out most of the star's light so thatthe camera can record the much less intense reflected light from surroundingobjects.
Any possible planet pictures are at least a year away. That's how long it will takeresearchers to fully calibrate the new instrument and test its effectivenessafter what Golimowski said would be "a very rough ride" aboard theSpace Shuttle. Many of the selected targets over the next 12 months will beobjects that don't require the high precision in tracking and locking onto anobject during multiple orbits of the observatory.
"If it looks feasible for finding planets, then we'd do it next year,"Golimowski said.
More than 400 minutes of observing time have been reserved for planet hunting aroundthe Alpha Centauri stars.
Young and strange solar systems
The reinvigorated Hubble will contribute to the investigation of other solarsystems in other ways, too.
A separate 3-year effort will employ the camera to look for subtle movements in anearby failed star, called a brown dwarf, in hopes of indirectly detecting aplanet around it.
The brown dwarf, called Gliese 229B, orbits a normal star. If Gliese 229B itselfharbors a planet, then the brown dwarf would wobble slightly under thegravitational tug of the smaller object. Our own Sun, for example, wobbles adistance about equal to its diameter due to the pull of the planets, Golimowskisaid.
In a series of observations, researchers will study the brown dwarf's orbitalmovement around its host star, Golimowski explained. They'll also note therelatively fixed position of more distant background stars. All thesemeasurements would help them detect slight perturbations in the path of Gliese229B that would indicate a Jupiter-sized travelling companion.
Wild places
The prospect of a planet orbiting a failed star that in turn orbits a normal starmight seem farfetched. Recent discoveries, however, have shown that solarsystems come in many shapes, sizes and configurations.
In one recent example, a planet was found orbiting a star that is 13 times biggerthan our Sun. In another, an apparent brown dwarf was discovered in anincredibly tight orbit around a star. And last June, researchers announced thatbrown dwarfs themselves sometimes have dust disks -- stuff that could possiblybecome planets.
"Our preconceived notion of what planetary systems should look like has been turnedon its head." Golimowski says. "We're not going in with anypreconceptions or biases about what we might find."
Hubble should contribute valuable data to a mounting effort to determine the varietyof ways in which solar systems form. Its most immediate discoveries will likelycome from the ACS's observations of clouds of dust that surround young starsand represent solar systems in formation.
To aid in examining dust, astronauts will also attempt to revive Hubble's disabledNICMOS (Near Infrared Camera and Multi-Object Spectrometer) instrument. Thisinfrared camera detects heat rather than visible light -- crucial for studyingspace dust, which can be virtually invisible in optical wavelengths.
NICMOS was installed on Hubble in 1997 and stopped working in January 1999.
Next page: What NICMOS will do
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