Scanning the unknown A new telescope may unlock space’s secrets
When he flies to Hawaii, Canadian astronomer Robert Garrison takes a parka and other winter clothing. That is because he spends nearly all of his time in the American state at a joint Canadian-French astronomical observatory located 14,000 feet above sea level at the summit of a chilly, arid mountain. The mountaintop on the island of Hawaii is considered one of the best sites on Earth for studying the universe, said Garrison, a University of Toronto astronomy professor. But even there, the Earth’s atmosphere distorts and blurs light from distant stars and galaxies. Now, space scientists around the world are eagerly awaiting the lunch of a $1.85-billion, American-built telescope that is expected to revolutionize astronomy by operating outside the Earth’s disruptive atmosphere. Said Houston-based astronomer C. Robert O’Dell, who spent 11 years supervising the development of the telescope: “With one sweep, we will make the jump in performance that Galileo did with the first telescope.”
If it performs according to expectations, the space telescope will allow astronomers to peer farther into the universe than ever before. A mission by the U.S. space shuttle Discovery that would have carried the telescope into space was aborted last week because of a problem in the auxiliary power unit. But scientists say that after the telescope reaches its orbit, probably later this month, they will be able to see seven times farther into the universe than they can from Earth and perhaps examine the very beginnings of time.
American and Canadian astronomers predict that the telescope will help them determine, with reasonable precision, the size, age and potential fate of the universe. They also say that it will lead to dozens of new discoveries and new fields of study. Said John Bahcall, president-elect of the American Astronomical Society: “If we don’t find things we haven’t thought of before, it’s an indication that the Deity was deficient in his imagination when he stocked the universe.”
Named after the American astronomer Edwin Hubble, who in 1929 discovered that the universe is expanding, the telescope was financed 85 percent by the Washington-based National Aeronautics and Space Administration and 15 per cent by the European Space Agency. But hundreds of North American and European astronomers and engineers actually designed and developed the device. Those scientists expect that they will soon be able to explore the very edges of the universe, and perhaps witness the birth of stars and galaxies.
As well, they expect to investigate with uprecedented precision such mysterious phenomena known as quasars, that is thought to be associated with them. And some astronomers will be looking for stars, like the Earth’s own sun, that have planets orbiting them. Said Bruce Gillespie, an astronomer with the Baltimore-based Space Telescope Science Institute, which oversees the operation of the telescope: “We are expanding the horizons of man’s consciousness.”
After nearly 20 years of design and development, the telescope that is scheduled to go into orbit 360 miles above the Earth is huge: 43 1/2 feet long, 14 feet in diameter and 12 tons in weight. The heart of the telescope is an 1,825 lb. mirror, measuring 94 1/2 inches across, which will capture visible and ultraviolet light from stars and a variety of cosmic objects. So precise is it that scientists compare it to a golfer hitting a ball in Maryland and routinely getting a hole-in-one in California. They also say it possesses the accuracy required to aim a laser beam from Washington at a nickel in New York City and hold it on target for 24 hours.
By operating outside the Earth’s atmosphere, the telescope will be able to focus the light into images of unprecedented clarity and precision, said O’Dell. The captured and focused light will undergo analysis by six highly sophisticated onboard instruments. They will also transform the light energy into electronic signals, which will be relayed to a receiving station in New Mexico, said Gillespie. He added that the telescope is designed to process and relay vast amounts of information 24 hours a day. The data will be stored electronically.
The Hubble, designed to operate for 15 years, will be serviced and repaired in orbit by space shuttle astronauts. John Hutchings, an astronomer with the National Research Council’s Dominion Astrophysical Observatory in Victoria, was a member of the team that designed the telescope’s $72-million high-resolution spectograph – a device that analyses ultraviolet light from stars, permitting astronomers to determine a star’s mass, chemical composition and velocity. Hutchings said that the telescope has been designed in such a way that the onboard instruments can be removed and replaced as new, more sophisticated equipment becomes available.
Because of the extraordinary capabilities of the telescope, astronomers have been competing intensely for the privilege of using it. Gillespie said that, during the first year of operation, half the available time has been reserved for about 80 American, Canadian and European scientists who worked on the design and development. The remaining time has been allocated on a competitive basis. Gillespie said that teams of scientists from around the world submitted 556 research proposals, but independent juries of astronomers selected only 162 proposals most likely to prove valuable.
Although many of the participating scientists will be exploring vastly different parts of the universe, several will be wrestling with fundamental issues about the size and age of the cosmos. Astronomers currently theorize that the universe is between 10 billion and 20 billion years old. O’Dell said that soon they should be able to provide a more precise answer.
Over the next 12 months, about two dozen Canadian astronomers are expected to take part in research projects using the Hubble. Hutchings, for one, said that he has about 10 projects planned, including a study of quasars. James Hesser, a fellow astronomer at the Victoria observatory, said that he plans to lead a 15-member Canadian-American research team studying star clusters – groups of several hundred to one million stars that orbit around the centre of a galaxy. John Caldwell, an astronomer at Toronto’s York University, said that he will examine a star in an obscure constellation called Pictor. A gigantic dust ring that is larger than the Earth’s solar system orbits the star. Added Caldwell: “Planets may be condensing out of the dust.”
The advent of space-based astronomy will not make earthbound observation of the universe obsolete. Indeed, the world’s largest telescope, a 393-inch, $112-million giant, will begin operating next year on the same Hawaiian mountaintop as the Canada-France observatory. Gillespie said that discoveries made through the Hubble may sometimes lead to follow-up studies using earthbound observatories. Alternatively, astronomers who reach the limits of cosmic discovery on Earth will be able to continue their work using the Hubble. For many astronomers, the combined power of the Hubble telescope and everlarger earthbound observatories promises to revolutionize mankind’s ability to explore our universe.