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32 Cards in this Set
- Front
- Back
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Geocentric model |
Geocentric means "Earth-centered." In the geocentric model, the sky, or heavens, are a set of spheres layered on top of one another. |
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Heliocentric model |
Nicolaus Copernicus proposed that Earth and all the other planets orbit the Sun. With the Sun at the center, this model is called the heliocentric model or "sun-centered" model of the universe |
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Moon |
Galileo discovered that the planet Jupiter has moons orbiting around it. |
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Nebula |
According to this hypothesis, the Sun and the planets of our solar system formed about 4.6 billion years ago from the collapse of a giant cloud of gas and dust, called a nebula. |
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Nebular hypothesis |
The most widely accepted explanation of how the solar system formed is called the nebular hypothesis. |
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Solar system |
Humans' view of the solar system has evolved as technology and scientific knowledge have increased. |
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Day |
earth rotates on its axis once per day, by definition. Earth orbits the Sun once every 365.24 days, which is defined as a year. Earth has one large moon, which orbits Earth once every 29.5 days, a period known as a month. |
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Inner planets |
The inner planets, or terrestrial planets, are the four planets closest to the Sun: Mercury, Venus, Earth, and Mars. |
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Terrestrial planets |
The inner planets, or terrestrial planets, are the four planets closest to the Sun: Mercury, Venus, Earth, and Mars. |
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Year |
Earth rotates on its axis once per day, by definition. Earth orbits the Sun once every 365.24 days, which is defined as a year. |
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Galilean moons |
These moons — Io, Europa, Ganymede, and Callisto — were first discovered by Galileo in 1610, so they are sometimes referred to as the Galilean moons |
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Gas giants |
These planets are much larger than the inner planets and are made primarily of gases and liquids, so they are also called gas giants. |
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Great Red Spot |
The Great Red Spot is an enormous, oval-shaped storm found south of Jupiter’s equator. |
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Outer planets |
The four planets farthest from the Sun are the outer planets. |
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Planetary rings |
They all also have planetary rings, composed of dust and other small particles that encircle the planet in a thin plane. |
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Asteroid |
Asteroids are very small, rocky bodies that orbit the Sun. |
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Asteroid belt |
The majority of the asteroids are found in between the orbits of Mars and Jupiter, in a region called the asteroid belt. |
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Comet |
Comets are small, icy objects that have very elliptical orbits around the Sun. |
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Dwarf planet |
The dwarf planets of our solar system are exciting proof of how much we are learning about our solar system. |
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Kuiper belt |
The Kuiper belt (pronounced “KI-per”) contains not only comets, but asteroids, and at least two dwarf planets. |
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Meteor |
A meteor, such as is a streak of light across the sky. |
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Meteor shower |
When Earth passes through a cluster of meteoroids, there is a meteor shower. |
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Meteoroid |
Meteors are called meteoroids before they reach Earth’s atmosphere. |
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Mercury |
the chemical element of atomic number 80, a heavy silvery-white metal that is liquid at ordinary temperatures. |
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Venus |
the Roman goddess of beauty and love, or the second planet from the sun. |
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Earth |
the planet on which we live; the world. |
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Mars |
impair the appearance of; disfigure. |
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Jupiter |
Jupiter is largely composed of gases |
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Saturn |
Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. |
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Uranus |
the sky personified as a god and father of the Titans in Greek mythology. |
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Neptune |
Neptune is named for the Roman god of the sea |
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Pluto |
Neptune is similar in size and composition to Uranus. |
