Astronomy Flashcards
Asteroids
small, rocky bodies in the sun’s orbit
Neptune
the eighth planet from the sun; outside the asteroid belt; blue because methane in the air absorbs red light. It emits more energy than it receives from the sun.
White Dwarf
a small star with high density; often the size of a planet
Sedna
another dwarf planet; much farther from the sun than Pluto;
Solar System
A star, as well as the planets, satellites, asteroids, and all the other objects orbiting it. They travel together through space.
Venus
Planet #2. Inner planets are in the asteroid belt. It is slightly smaller than Earth and has the same mass and chemical makeup.
Satellite
Moons which orbit the planets
Exoplanets
planets which orbit stars outside our own solar system
Planet
a body going around a star that is big enough to clear out the junk in its path and has enough gravity to stay round.
A body moving in orbit around a star which has enough gravity to make it round.
Period (of a Comet)
the amount of time it takes for a comet to orbit the sun
Moons
satellites which orbit planets
Binary Stars
a system with two stars; either both stars move around the same point or one star moves around the other.
Saturn
the sixth planet from the sun, an outer planet (outside the asteroid belt), the least dense planet, and it has a complicated ring system.
Uranus
the seventh planet from the sun, outside of the asteroid belt, mostly made of rock and ice, with 27 known moons.
Comet
A body made of ice and dust that circles the sun. It has a “tail” made of gas and dust.
Nebula
a gas and dust cloud in space
Dwarf Planet
a small planet not large enough to clear its orbit of debris
Ex: Pluto
Earth
the third planet from the sun; an inner planet (inside the asteroid belt); the only known livable planet; 71% of its surface is covered with liquid water
Meteorite
what remains of a meteor after it hits the surface of the earth
Oort Cloud
a shell of comet bodies which orbit the sun
Neutron Star
a small star with high density; made of closely packed neutrons
Meteor
a meteoroid that has entered Earth’s atmosphere
Red/Blue Dwarfs
Red dwarfs are small stars with low mass and a cool surface. Blue dwarfs form from red dwarfs when all the hydrogen is used up.
Red/Blue Giants
Large stars; red giants are bright but have cool surfaces, while blue giants are bright but have hot surfaces.
Celestial Bodies
a physical object in space which has observable characteristics
Ex: planet
Constellations
a star grouping which forms a pattern; we have ascribed images to the constellations
Black Hole
an object with enough gravity to stop radiation or matter from escaping.
Pluto
Until recently, it was called the ninth planet from the sun. Now, it’s generally called a minor planet or dwarf planet, and it has five moons.
Galaxies
a system of stars and their systems held together by gravity
Jupiter
the fifth planet from the sun. It is an outer planet, which means it is outside of the asteroid belt. It is the biggest planet and has more mass than all the other planets put together. has four really big moons; 90 percent hydrogen and 10 percent helium.
Mars
the fourth planet from the sun; an inner planet (inside the asteroid belt); the “Red Planet”; home to Olympus Mons, the highest mountain in the solar system;
Absolute Magnitude
the actual amount of light a star gives off
Stars
a gaseous body which produces radiant energy through nuclear fusion reactions
Pulsar
A neutron star that spins quickly and sends out radio waves in pulses.
Mercury
the first planet to orbit the sun. It is an inner planet, which means it is inside the asteroid belt. It is about the size of Earth’s moon and has a large iron core.
