space
a light year
the distance that light travels through a vacuum in a year, one light year = 9.46 x 10^12 km
order of the planets
mercury, venus, earth, mars, Jupiter, Saturn, Uranus, Neptune, pluto
location of the asteroid belt
in between mars and jupiter
asteroids vs meteors vs meteoroids vs meteorites
asteroids are small objects made of rock and metal between mars and Jupiter. Meteoroids are chunks of rock smaller than asteroids. Meteors are meteoroids that have entered the earth's atmosphere. Meteorites are meteors that have crashed into the ground.
absorption spectrum
when starlight passes through a cloud of gas or the star's atmosphere, some light is absorbed and some is transmitted through the gas. wavelengths of light that are absorbed depend on what elements and compounds it is made of. The absorption spectrum has colours corresponding to the wavelengths of light that are absorbed. Dark lines represent wavelengths that are transmitted/reflected.
life cycle of a star
Starts as a nebula, then becomes a protostar, then becomes a main sequence star when it is turned on. It then becomes a red giant or supergiant. Bigger stars become supernovas, which then become neutrons stars, but if they are massive they become black holes. Smaller stars become planetary nebulas, than white dwarfs, and then black dwarfs.