solar system key terms

perihelion

the point in a planets orbit when its closet to the sun

satellite

any object that moves around another object

moon

a natural object in space that orbits a planet

orbit

elliptical path in which an object in space moves around another object in space

planet

nearly round object in space that dominates its orbit around a star

nucleus

the small solid core of a comet

eccentricity

the shape of an orbit in regards to the distance between the foci compared to the length of the long axis

dwarf planet

a smaller, round, planet like object in space that orbits a start bit does not dominate its orbit around that star

coma

the glowing gases surrounding the core of a comet

sun

the closest star to earth and the center of our solar system

terrestrial

earth like, mostly rocky

jovian

Jupiter like, large and made mostly of gases

aphelion

the point in a planets orbit when it is farthest from the sun

nebula

cloud of dust and gas in space

astronomical unit

the average distance between the earth and sun approximately 150 kilometers

star

glowing hot ball of gases in space fueled by nuclear fusion in its core

nebular theory

describes how the solar system formed due to gravity pulling the mass of a rotating cloud of dust and gas together into a star and surrounding plants and moons

solar system

the sun the planets and their satellites and all other objects that orbit the sun

meteor shower

when a large number of relatively small, solid objects enter earths atmosphere and vaporizes as they fall to earth, typically at the same time each year as earth passes through a comets orbital path

planetesimals

small, irregularly shaped bodies that through accretion of colliding bodies, grow into planets; protoplanets

martian

having to do with mars

asteroid

small, irregular shaped rocky typically found between the orbits of mars and jupiter

comet

a small body of rock and metallic material held together by ices that orbit the sun, commonly in long, elongated orbits

meteoroid

relatively small solid object traveling through space

meteor

relatively small, solid object that enters earths atmosphere and vaporizes as it falls to earth; also known as a 'shooting star'

meteorite

relatively small, solid object that enters earths atmosphere and strikes earth before it completely vaporizes

crater

round depression on the surface of a planet or moon formed from the impact of a meteorite or similar solid object