The universe holds more clues to its origin than mere mortals can see with the aid of an optical telescope. Heavenly bodies such as quasars emit electromagnetic waves that are "visible" through instruments - radio telescope antennas - that play back these frequencies to an earthbound computer. Radio telescopes can paint an accurate picture that just became sharper.
Researchers at the National Radio Astronomy Observatory in Socorro, New Mexico, have successfully generated the first images from a radio telescope system that includes a telescope antenna in space. These results give astronomers the giant radio telescope system they've long sought. But the quest for size isn't just about bragging rights, notes Dr. Jonathan Romney, scientist with the NRAO.
"With a large telescope, we can get more accurate data on the inner parts of black holes and quasars," said Romney.
Radio telescope antennas pick up the radio waves generated by the energy given off by such matter as quasars that is, in many cases, so far out in space that optical telescopes cannot pick it up.
While optical and radio observations augment each other and paint a more complete picture of the universe, the level of resolution of optical telescopes outpaces that of the radio antennas. To have a radio telescope antenna system with the resolution and detail of an optical telescope, researchers would have to build an "impossibly large" antenna that would be miles in diameter, Romney said.
To get around this physical limitation, scientists in the 1950s devised a network of small antennas that would pepper the globe. The combined reception of these antennas would equal that of the large radio telescope antenna. One system - Very Long Baseline Array - used 27 antennas with a maximum separation of 20 miles. A subsequent system - Very Large Array - used 10 antennas spread 5,000 miles apart.
But the level of detail was limited - this time, by the circumference of the earth. Lofting an antenna skyward would help researchers get the detail they wanted.
The system that generated the Socorro images uses a combination of a Japanese satellite, launched in April, with the National Science Foundation's VLBS and VLA systems. The satellite, which bears the radio telescope antenna, at its lowest is 1,000 kilometers from earth and roves as high as 22,000 kilometers, Romney said. This added distance generates images that have more than 100 times the detail of those captured by the Hubble Space Telescope.
Radio waves picked up by satellite are sent to recording stations at the earthbound radio antennas, which generate magnetic tapes. These tapes are then fed into a computer, which interprets the data and generates the images.
And that level of detail will open the door to the study of these faraway bodies that could give astronomers a better understanding of how their own terra firma was formed.
US researchers will have help in this department, too, as the project will also use data captured by radio telescopes in Japan, Europe, and Australia.
