Our Solar System Flashcards
Define solar system.
The sun and the eight planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune) and other celestial bodies that orbit it.
Define orbit.
The elliptical path that a body traverses as it travels around a larger body. Shape determined by the movement of the own body and the gravitational pull of the bigger body.
Define terrestrial planets.
Like the Earth. Solid exterior, molten heavy-metal core, few moons. Includes low escape velocity. Terrestrial planets include Mercury, Venus, Earth, and Mars. Inner planets.
Define Jovian planets.
Outer planets. Similar to Jupiter. Have thick atmospheres, high escape velocities, and are massive. Includes Jupiter, Saturn, Uranus, and Neptune.
Define meteor.
The term for when an asteroid enters the Earth’s atmosphere. Also known as shooting stars.
Define comet.
Frozen gasses trapped in a rocky, metallic center. Frozen gasses evaporate near the sun. Called dirty snowballs. Contain highly elliptical orbits. Believed to originate in the Oort Cloud.
Define asteroid.
Most lie between the orbits of Mars and Jupiter. Have irregular shapes. Many leave orbit and impact planets. Believed that Jupiter’s gravity prevented bodies to coalesce into a planet.
Define meteorite.
Asteroids that strike the Earth’s surface.
Define meteoroid.
A small body moving in the solar system that would become a meteor if entered the earth’s atmosphere.
Define highlands.
Bright. Densely cratered. makes up most of the moon. Originally the outermost layer of the moon.
Define marias.
Dark regions. Fairly smooth landscape. Originated from meteorite impact and lava flooding the surface. Not found on the far side of the moon.
Define craters.
Feature of the moon created by an impact from a meteoroid which produces ejecta and occasional rays.
Define retrograde motion.
Motion of a planet moving in the opposite direction of the normal direction of planetary motion as observed from Earth.
Define rays.
Long trails of ejecta.
Define rilles.
Meandering valley-like features on the Moon’s surface.
Define nebula.
A cloud of gas and dust in outer space. The birthplace of stars.
Define dwarf planet.
Planets that have not cleared the area around its orbit. E.g.: Pluto, Ceres, and Eris.
Define planetesimal.
A body that could or did come together with many others under gravitation to form a planet.
Define asteroid belt.
A torus-shaped region in the Solar System, located roughly between the orbits of the planets Jupiter and Mars. Occupied by asteroids.
