| A | B |
|---|
| the study of the moon, stars, and other objects in space | astronomy |
| a rapidly spinning neutron star that produces radio waves | pulsar |
| the explosion if a dying supergiant star | supernova |
| a large cloud of gas and dust in space, spread out in immense volume | nebula |
| a substance that enters into a chemical reaction | reactant |
| the attraction between oppositley charged ions | ionic bond |
| the path of an object as it revolves around another object in space | orbit |
| a chemical bond formed when two atoms share electrons | covalent bond |
| a compound that consits of positive and negative charges | molecule |
| the blue-white hot core of a star that is left behind after its outer layers have expanded and drifted out into space | white dwarf |
| a combination of symbols that represents the elements in a compound | chemical formula |
| an object whose gravity is so strong that nothing can escape | black hole |
| a short easy way to show a chemical reaction using symbols | chemical equation |
| an ion that is made of more than one atom | polyatomic ion |
| a number in front of a chemical formula in an equation that indicates how many molecules or atoms of each reactant and product are involved in a reaction | coefficient |
| the two days of the year on which the sun reaches its greatest distance north or south of the equator | solstice |
| the principle stating that matter is not created or destroyed during a chemical reaction | law of conservation of mass |
| an atom or group of atoms that has become electrically charged | ion |
| the spinning motion of a planet on its axis | rotation |
| a contracting cloud of gas and dust with enough mass to form a star | protostar |
| the two days of the year on which neither hemisphere is tilted toward or away from the sun | equinox |
| a substance formed as a result of a chemical reaction | product |
| the small dense remains of a high mass star after a supernova | neutron star |
| the movement of an object around another object | revolution |
