A theory that says the universe began as a small point that expanded rapidly about 13.7 billion years ago
the Big Bang theory
A pervasive radiation, also known as cosmic microwave background, seen in every direction that is evidence of the big bang theory
primordial radiation
The specific wavelengths of electromagnetic radiation emitted by the electrons of atoms or molecules as those electrons return to a lower and more stable energy state
Emission spectra
One of the primary substances that make up matter and cannot be chemically broken down or converted into other substances; defined by the atomic number
Elements
The explosion of a massive star at the end of its life cycle
Supernova
A unit of length equal to the distance that light travels through space in one year
Light year
The change in wavelength that allows us to determine if an object is moving toward us or away from us
redshirt and blueshift
The distribution of energy in wavelengths within a system
spectrum
The lightest noble gas,containing two protons and two electrons
Helium
All space and the matter space contains
universe
A reaction in which two light nuclei combine to produce a nucleus of heavier mass, resulting in the release of a large amount of energy
Nuclear fusion
The tiny, very dense, positively charged region in the center of an atom; made up of protons and neutrons
atomic nucleus
An element containing one proton and one electron that is a colorless, odorless, highly flammable gas when found in nature
Hydrogen
A large grouping of stars, planets, gas, and dust in space held together by gravity
galaxy