Radio telescopes allow scientists to study the universe in great detail.
Radio telescopes are devices that astronomers use to study the heavens, classifying bodies not by their emitted light, but by measuring other forms of radiation. Radio telescopes usually take the form of enormous parabolic dishes, designed to concentrate radio waves at the receiver, and usually operate far from cities to avoid interference. Radio astronomy has led to a new understanding of the universe through analysis of these emissions.
Invention
In 1933, a physicist named Karl Jansky was performing experiments related to radio waves and natural electromagnetic fields when he discovered a strange interference pattern. After working to isolate it, he discovered the mystery radio signal was coming from the Milky Way, confirming the theories of earlier astronomers that stars and other heavenly bodies emitted radiation other than visible light. This led to the development of radio astronomy and the development of devices designed to detect faint radio waves from across the universe.
Radio Telescopes
Typically, a radio telescope uses a large reflector dish to collect and concentrate radio waves at a receiver. Some telescopes consist of one large dish, while others may contain an array of smaller dishes, all of which focus on individual sources of emissions in the sky. As the Earth rotates, they can move to follow a single source, allowing the telescope or array to measure signals from a given point over a long period. Receivers log the signals at various frequencies, and computers synthesize the information to produce a more complete picture of the observed object.
Interferometry
One technique radio telescopes can employ to gather more information about the heavens is interferometry. When the same signal reaches two different receivers from a single source, it can arrive out of phase, meaning at a different point in its signal cycle. Scientists can superimpose these signals upon one another, using the differences to amplify weak signals or, if the phase difference is large enough, to flatten out interference. Interferometry can involve two separate receivers, or it can involve a single receiver detecting a single signal at two different points in the Earth's rotation. By combining the information from multiple observations, scientists can derive much more information from a single source than they could with a single receiver or array.
Radio Astronomy
The benefit of radio astronomy is it gives scientists a much clearer view of the heavens than simple optical observation. Two objects may look similar to the eye, but by measuring their radio emissions, astronomers can discern differences between the objects, such as their age, rotation and even the elements those objects contain. Additionally, radio astronomy can identify and allow study of objects invisible to the naked eye, such as extremely distant stars or black holes.
Tags: radio waves, radio astronomy, Radio telescopes, single source, concentrate radio, concentrate radio waves
