Learn about radio telescopes with this video.
  • On November 1, 1963, the Arecibo Observatory in Arecibo, Puerto Rico, officially opened to scientists from the United States and around the world. The observatory includes what was at the time the largest single-dish radio telescope in the world. (In 2016, China built an even larger radio telescope.)
    Radio telescopes gather data from radio waves, which have the longest wavelengths on the electromagnetic spectrum. The Arecibo radio telescope uses a large, dish-shaped antenna to direct radio waves from a specific region in the sky.
    The radio facilities at the Arecibo Observatory serve astronomers, planetary scientists, and atmospheric scientists. Data from the observatory helped astronomers prove the existence of neutron stars—the densest stars in the known universe. Recently, planetary science researchers analyzed data from Arecibo to detect the possible presence of ice on the planet Mercury. Atmospheric science researchers at the observatory study the properties of Earth’s airglow—the faint light emitted by our planet’s atmosphere.
    Several geographic factors made Arecibo the perfect spot for the massive dish, which measures 305 meters (1,000 feet) in diameter. First, Arecibo is a rural area far from Puerto Rico’s big cities. (Radio telescopes are ideally located in isolated areas, where few radio waves compete with the signals studied by scientists.) Second, Arecibo has a karst landscape, which allowed engineers to build the dish directly into a deep natural sinkhole. This allows the telescope even less radio “interference” from the surrounding area. Third, Puerto Rico is relatively close to the Equator, where scientists could best study planets that pass overhead.
  • Term Part of Speech Definition Encyclopedic Entry
    airglow Noun

    faint light emitted by the upper atmosphere of Earth or another planet.

    analyze Verb

    to study in detail.

    antenna Noun

    structure through which electromagnetic signals are received.

    astronomer Noun

    person who studies space and the universe beyond Earth's atmosphere.

    atmosphere Noun

    layers of gases surrounding a planet or other celestial body.

    Encyclopedic Entry: atmosphere
    atmospheric science Noun

    study of the atmosphere's physical characteristics, motions, and processes, and the way in which these factors affect the rest of our environment.

    compete Verb

    to work against someone or something else for an award or acknowledgment.

    data Plural Noun

    (singular: datum) information collected during a scientific study.

    dense Adjective

    having parts or molecules that are packed closely together.

    detect Verb

    to notice.

    diameter Noun

    width of a circle.

    electromagnetic spectrum Noun

    continous band of all kinds of radiation (heat and light).

    emit Verb

    to give off or send out.

    engineer Noun

    person who plans the building of things, such as structures (construction engineer) or substances (chemical engineer).

    Equator Noun

    imaginary line around the Earth, another planet, or star running east-west, 0 degrees latitude.

    Encyclopedic Entry: equator
    factor Noun

    element contributing to an event or outcome.

    geographic Adjective

    having to do with places and the relationships between people and their environments.

    ice Noun

    water in its solid form.

    Encyclopedic Entry: ice
    ideal Adjective


    interfere Verb

    to meddle or prevent a process from reaching completion.

    isolate Verb

    to set one thing or organism apart from others.

    karst Noun

    landscape made of limestone.

    Encyclopedic Entry: karst
    landscape Noun

    the geographic features of a region.

    Encyclopedic Entry: landscape
    locate Verb

    to find or identify a place.

    massive Adjective

    very large or heavy.

    neutron star Noun

    very dense stellar remnant formed by the collapse of a massive star in a supernova.

    observatory Noun

    place or building equipped and used for making observations of astronomical, meteorological, or other natural phenomena, usually equipped with powerful telescopes.

    planet Noun

    large, spherical celestial body that regularly rotates around a star.

    Encyclopedic Entry: planet
    planetary science Noun

    study of planets and planetary systems, particularly our own solar system.

    radio wave Noun

    electromagnetic wave with a wavelength between 1 millimeter and 30,000 meters, or a frequency between 10 kilohertz and 300,000 megahertz.

    region Noun

    any area on Earth with one or more common characteristics. Regions are the basic units of geography.

    Encyclopedic Entry: region
    rural area Noun

    regions with low population density and large amounts of undeveloped land. Also called "the country."

    Encyclopedic Entry: rural area
    signal Verb

    to communicate using signs.

    sinkhole Noun

    hole formed in a rock or other solid material by the weight or movement of water.

    Encyclopedic Entry: sinkhole
    specific Adjective

    exact or precise.

    telescope Noun

    scientific instrument that uses mirrors to view distant objects.

    universe Noun

    all known matter, energy, and space.

    wavelength Noun

    the distance between the crests of two waves.