Parabolic antennas are everywhere -- on top of radio towers, in your neighbor's back yard, and on top of your local television station. What we often call "satellite dishes," are in fact huge antennas that use their parabolic shape to focus the reception of radio waves. We use these antennas to receive all types of information, such as television, radio, and cellular phone signals. In fact, much of our communication technology depends on these antennas to send and receive information.
In addition to supporting our systems of communication, these antennas play an essential role in the telescopes that we use to peer into the depths of the universe. Early telescopes used a parabolic lens to collect light from distant stars, but many of today's telescopes, using parabolic antennas, collect radio waves. These radio telescopes, allow scientists to probe deeper into space than ever before.
One of the most famous radio telescopes is The Very Long Baseline Array telescope (VLBA), which consists of 10 huge parabolic antennas that range across the continental U.S., Hawaii, and the U.S. Virgin Islands. Each antenna gathers its own data and sends it to the telescope's headquarters, where a computer compiles the information and combines it to give a single complete picture. The series of antennas, or array, spans 5,000 miles and is currently being used to observe very distant objects, such as quasars, pulsars, neutron stars, black holes, and other galaxies. Outer space, however, is not the only focus. The VLBA can also be focused closer to home to observe the movement of the earth's continental plates and help track other natural phenomena, such as earthquakes and volcanos.