Astronomy

A:

Earth is considered to be the "third rock from the sun." That phrasing is used because Earth is the third planet from the sun, as well as being a terrestrial (rocky) planet.

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  • What Is a Shooting Star?

    Q: What Is a Shooting Star?

    A: Although a shooting star looks like a star shooting across the sky, it's actually a meteor, or small rock that hits Earth's atmosphere. Because of the speed at which the meteor, or meteoroid, is traveling it burns and releases a glow.
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  • What Is the Circle of Illumination?

    Q: What Is the Circle of Illumination?

    A: The circle of illumination is the line that separates the Earth to create equal parts of day and night. It passes through the poles and allows the entire Earth to have an equal amount of time spent during the daylight and nighttime hours.
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  • How Would You Describe a Solar Eclipse?

    Q: How Would You Describe a Solar Eclipse?

    A: A solar eclipse occurs when the moon moves directly between the Earth and the sun. The moon's shadow travels over the surface of the Earth and blocks out the light from the sun seen on Earth.
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  • What Is a Constellation?

    Q: What Is a Constellation?

    A: The general English definition of constellation is a group or configuration of objects, characteristics, ideas, feelings, etc, as in "a constellation of qualities." The noun constellation is used in astronomy, astrology and general English.
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  • What Types of Equipment Do Astronomers Use?

    Q: What Types of Equipment Do Astronomers Use?

    A: According to NASA, modern astronomers’ tools include advanced telescopes capable of studying light reflected from the sun, moon, planets, comets and stars. Radio telescopes are utilized in the study of radio waves, while space-borne gamma ray telescopes aid in the study of gamma rays.
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  • What Is Jupiter's Atmosphere Made up Of?

    Q: What Is Jupiter's Atmosphere Made up Of?

    A: The atmosphere of Jupiter consists of 90 percent hydrogen gas and nearly 10 percent helium. However, its atmosphere has trace amounts of ammonia, sulfur and water vapor. Jupiter is a gas giant that is also the biggest planet in the solar system.
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  • What Is an Elliptical Orbit?

    Q: What Is an Elliptical Orbit?

    A: Elliptical orbits are the paths taken by objects as they fly around a massive object, such as the sun or Earth. Such orbits are not round as is commonly supposed; instead, they orbit the massive body in the shape of an ellipse. Ellipses are like circles that have been elongated slightly, and they are also referred to as ovals.
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  • How Did the Constellation Orion Get Its Name?

    Q: How Did the Constellation Orion Get Its Name?

    A: Stargazers in ancient Greece observed the "pictures" formed by stars and named the Orion constellation after a mythological hunter. Many origin stories exist, but one popular version recounts Orion's quest to defeat a giant scorpion sent by Gaia, the goddess of Earth, according to the Windows to the Universe.
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  • Are Stars Bigger Than the Sun?

    Q: Are Stars Bigger Than the Sun?

    A: Stars exist that are both bigger and smaller than the sun. The sun has a radius of 1.4 million kilometers and, relative to other stars, is an average size.
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  • What Are Some Solar System Project Ideas?

    Q: What Are Some Solar System Project Ideas?

    A: A popular solar system project idea is the construction of a solar system model. While the hanging Styrofoam ball model is an easy-to-create option, constructing the solar system in panoramic form in a shoe box can also be fun.
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  • What Did Galileo Discover?

    Q: What Did Galileo Discover?

    A: After Galileo built his first telescope in 1609, he observed and described the landscape of the moon, discovered four of the moons of Jupiter, discovered the phases of Venus, and discovered sunspots. Galileo's discovery of sunspots supported the idea of heliocentrism, a model that places the sun at the center of the universe with the planets orbiting around it.
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  • What Do You Call a Person Who Studies Space?

    Q: What Do You Call a Person Who Studies Space?

    A: A person who studies space is called an astronomer or astrophysicist. These types of scientists are responsible for the discovery of all of the planets, stars, asteroids and other extraterrestrial objects.
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  • Why Do Stars Pulsate?

    Q: Why Do Stars Pulsate?

    A: Stars appear to pulsate and twinkle in the night sky due to the refraction of light through the Earth's atmosphere. When the light from a star enters the atmosphere, air molecules bounce and deflect the light rays, slightly altering the apparent position and intensity of the star.
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  • How Long Would It Take a Passenger Plane to Fly Around the Sun?

    Q: How Long Would It Take a Passenger Plane to Fly Around the Sun?

    A: A passenger airplane, flying at 600 mph, could circle the sun in just over six months. According to Space.com, the sun is a nearly perfect sphere, and there is essentially no difference in circumference at its equator and the circumference from pole to pole.
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  • How Big Is Titan?

    Q: How Big Is Titan?

    A: Titan is 3,200.051 miles in diameter. It the second-largest moon out of hundreds in the solar system and is Saturn's largest. Titan's mass is 80 percent greater than that of the Earth's moon, and its diameter is 50 percent longer than the diameter of the Earth's moon.
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  • Where Does the Sky End?

    Q: Where Does the Sky End?

    A: The sky ends at the Karman line, which is located at about 67 miles above sea level. Above this line, space begins. However, technically, the sky does not end so much as the atmosphere, or sky, thins until there is no oxygen left.
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  • What Happens to Stars As They Age?

    Q: What Happens to Stars As They Age?

    A: Stars on the main sequence that are the same size as the Sun begin as yellow stars and turn into red giants as their hydrogen fuel runs out. Other stars shrink or explode, depending on their size.
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  • How Does Gravity Keep Us on Earth?

    Q: How Does Gravity Keep Us on Earth?

    A: Gravity is one of the fundamental forces of the universe, and it keeps us on Earth because it is relentlessly attractive. Every massive particle exhibits gravity by pulling closer to every other particle. The strength of this interaction is dependent on two quantities: the amount of mass and the distance between objects. It is possible to escape Earth's gravity if you have enough energy to speed up sufficiently.
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  • What Causes a Lunar Eclipse?

    Q: What Causes a Lunar Eclipse?

    A: Lunar eclipses are caused when the moon travels through the Earth’s shadow. Complete lunar eclipses are rare, but partial lunar eclipses may occur up to four times per year.
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  • How Does the Astrolabe Work?

    Q: How Does the Astrolabe Work?

    A: Astrolabes work by presenting users with a graphic interface that makes it relatively easy to compute the positions of the sun, the moon and the stars. Astrolabes can be used for navigation as well as predicting the exact times for sunrise and sunset. Turned on its side, an astrolabe can be used as a mechanical calculator akin to a slide rule.
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  • What Is a Burnt-Out Star Called?

    Q: What Is a Burnt-Out Star Called?

    A: A burnt-out star is called a white dwarf. A white dwarf results after a star’s nuclear fuel burns out, which causes it to collapse or implode. While it has a mass similar to that of the sun, its radius is similar to that of the Earth.
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