Aside from the Hubble's impact on astronomy textbooks, it has also engaged the public's imagination. Many of its images are simply dazzling--revealing the cosmos as unexpectedly complex, bizarre and, in some aspects, strangely organic looking. Scientists note that Hubble snapshots of the chaos around black holes, glowing nebulas sprouting embryonic stars, a comet hitting Jupiter, exploding stars and so on convey soul-stirring ideas as well as eye candy.
Lead Hubble scientist David Leckrone, of NASA's Goddard Space Flight Center in Greenbelt, which operates the observatory, enthused, "Not since Galileo aimed a small 30-power telescope into the night sky in 1609 has humanity's vision of the universe been so revolutionized in such a short time span by a single instrument."
The headline-grabbing telescope has stirred resentment among some scientists who claim it attracts a disproportionate share of publicity and money. Some are critical of its price tag-expected to total $6 billion over its 30 years of design, development and operations.
But the interaction between the Hubble and other telescopes these days is often a collaboration rather than a competition. While a new generation of powerful ground-based telescopes are larger and collect more light, the Hubble augments their capabilities in important ways. Because it flies above the distorting, blocking atmosphere, it yields images of greater clarity and detail in both visible and infrared light, and it can see in ultraviolet wavelengths that cannot be studied at all from the ground.
As of early last year, said NASA chief scientist Edward Weiler, the Hubble had completed the "triple crown" of promises made decades earlier by its sponsors: to determine the age of the universe within a certain accuracy; to provide proof that massive black holes exist; and to detect the faintest and farthest objects in the cosmos.
The Hubble's measurements of stellar distances led to an estimate that the universe is about 13 to 15 billion years old. Previous estimates had ranged dramatically from as low as 10 billion to as high as 20 billion or more.
Among the telescope's other accomplishments, scientists list the following:
- Studies suggesting that supermassive black holes commonly lurk at the hearts of distant galaxies. (A black hole is a collapsed star whose material is so concentrated that nothing, including light, can escape its gravitational pull.)
- A live-action chronicle of the fragmented Comet Shoemaker-Levy smashing into Jupiter in 1994. The Hubble played a major role in a global observing campaign that provided humanity's first direct view of such a planetary collision.
- Refinements of ground-based telescope data showing that the expansion of the universe seems to be accelerating rather than slowing down as scientists had thought. This finding implies the existence of a mysterious "anti-gravity" energy that fills the vacuum of space and acts in opposition to gravity.
The telescope was named after flamboyant U.S. astronomer Edwin P. Hubble, a sometime lawyer, boxer and soldier, who first showed that galaxies exist beyond the Milky Way, our home galaxy, and that these conglomerations of stars are all flying apart from each other.
Researchers in the United States and Europe have scheduled special gatherings this month to celebrate the telescope's 10th birthday, including one in Munich on Thursday (April 27). The U.S. Postal Service has issued five new 33-cent stamps featuring luminous Hubble visions.
Scientists are developing a more advanced observatory to replace the Hubble. But with regularly scheduled "road side service" visits by astronauts who do routine maintenance and install new equipment, the space telescope is enjoying a healthy middle age, poised for one more decade of cosmic probing.