Hubble ‘Brain Surgery’ Promises Brighter View
High overhead, NASA astronauts are scheduled this week to begin repairs on the Hubble Space Telescope.
The 360-mile-high "brain surgery" in space, in the words of astronaut John Grunsfeld, promises a brighter view of the cosmos for Hubble astronomers and fans alike. Sometimes the two are interchangeable.
"We are waiting on the edge of our seats for the incredible results we will get from a repaired Hubble," says cosmologist Mario Livio of the Space Telescope Science Institute in Baltimore. "We are only going to get more great science."
"Hubble will go from a VW Super Beetle to a high-powered race car," says astronomer Julianne Dalcanton of the University of Washington-Seattle. Hubble will peer at stars and galaxies formed 500 million years after the Big Bang, equipped with a new camera 30 times more sensitive to light and a chemical spectrometer 10 times more effective. "We will be able to plan observations we never could before, simply because the telescope will be more efficient," Livio said in April.
Hubble has delivered so many astronomical findings, that picking out a "greatest hits" list is a challenge, Dalcanton says. When she wrote a retrospective of Hubble finds for the "Nature", she says, "I had to leave things out, there was just too much."
Among the highlights...
Cepheids, pulsating stars thousands of times brighter than our sun, serve as ready-made distance markers in space. Measuring Cepheids in galaxies - such as the Spiral Galaxy M100, above - allows astronomers to create a framework by which they can precisely gauge distances throughout the sky.
Images of the Orion Nebula, a star birth factory, revealed that the youngest stars are surrounded by dust disks buffeted by the winds from nearby exploding giant stars. These are exactly the conditions astronomers suspected would lead to solar system formation. More than 3,000 stars appear in this composite of 100 images.
After stars consume their hydrogen fuel, an explosion can't be far behind. Images of nearby explosions reveal the "light echoes" of blast waves shocking clouds of dust that escape from stars on the edge of eruption, such as this star 20,000 light years away on the outer edge of the Milky Way.
Hubble has observed the stars orbiting near suspected supermassive black holes, from which nothing - not even light - can escape, such as the Sagittarius A at the center of our own Milky Way galaxy. Hubble also has detected previously unsuspected middle-size black holes (merely 10,000 times more massive than the sun) in nearby galaxies. Above, a star cluster with a black hole in its dense core.
"Deep field" images surprised astronomers by showing that the most distant, and earliest, galaxies don't resemble the spiral and football-shaped galaxies of the modern universe but look more like "insects spattered on a windshield," Dalcanton says.
Age of the universe:
Hubble has honed the precision of the "Hubble constant" (also named for the astronomer Edwin Hubble), the measure of the universe's expansion rate. Hubble measurements of exploding stars in distant galaxies led to the 1998 discovery of "dark energy," the unexplained observation that galaxies across the cosmos are moving apart at an accelerating rate.
Remarkably, Hubble isn't a very advanced observatory compared with massive telescopes on Earth, such as the 33-foot-wide mirror of Hawaii's Keck telescopes, Dalcanton says. But its location in orbit frees it from clouds, atmospheric distortion and city lights on Earth, which makes it invaluable to astronomers. "It's hard to conceive of a world without Hubble," she says. "And the repairs will, hopefully, mean we won't have to."