Read the following passage and mark the letter A, B,C, or D on your answer sheet to indicate the correct answer to each of the questions from 26 to 35.
A radio telescope is a radio receiver that "sees" radio waves. Unlike a normal telescope, which sees light, a radio telescope is used primarily in the are a of astronomy because it can detect radio waves that are emitted by celestial objects. Such objects in space, also called radio objects, can be things such as hot gas, electrons, and wavelengths given off by different atoms and molecules.
The first radio telescope was invented by Grote Reber in 1937. He was an American who graduated with a degree in engineering. He went on to work as an amateur radio operator and later decided to try to build his own radio telescope in his backyard. Reber's first two radio receivers failed to pick up any signals from outer space, but in 1938, his third radio telescope successfully picked up radio waves from A radio telescope consists of a large parabolic-shaped dish antenna or a combination of two or more. The significance of the parabolic shape allows for the incoming radio waves to be concentrated on one focal point, allowing the signals to be picked up as strongly as possible. A larger dish means that more signals can be received and focalized.
In the late 1950s and early 1960s, the largest radio telescope of the time was invented with a seventy-six meter telescope although larger telescopes have been made since then. The largest current radio telescope in the world is the RATAN-600 in Russia, whose diameter is 576 meters. It has provided valuable feedback of the sun's radio wavelengths and atmosphere. The largest radio telescope in Europe is a 100-meter diameter telescope in Germany, and the largest radio telescope in the United States is the Big Ear in the state of Ohio. The largest array of telescopes is the Giant Metrewave Radio Telescope in India.
Radio telescopes have provided scientists with valuable information about our universe. One of the most important functions of radio telescopes is their ability to allow scientists to track different space probes, the unmanned space missions in outer space. Radio telescopes allow for the travel of space probes into places like the surface of Mars that are too dangerous for men to explore. With out radio wave technology, scientists would not know much of what inhabits the universe nor would they be able to see it. Radio waves are our eyes and ears in outer space.
Originally, this passage was probably published in ______.
A.a fashion magazine
B.a scientific journal
C.a business journal
D.a book on environment
