Chapter 1 Flashcards
Mass
A measure of the amount of matter in an object.
Measured in - kilograms(kg)
Distance
A measure of the length between 2 points in space, usually along a straight line.
Measured in - meters(m)
Speed
The rate at which an object covers distance.
Measured in - meters per second(m/s)
Velocity
The rate of change in displacement of an object with respect to time.
Measured in - m/s, with direction specified by a vector
Angular size
Apparent size of an object, as observed from a particular vantage point.
Measured in - degrees(°), arc-minutes(‘) and arc-seconds(“)
Parsec
A unit of distance used in astronomy
1 Parsec = 3.086 × 10^16 meters (about 3.26 light-years).
Speed of light
The speed at which the light travels in a vacuum.
1 ly - 3.00×108 meters per second (m/s).
Astronomical unit
A unit of measurement in astronomy which represents the average distance between the Earth and the Sun.
1 AU = 149.6 million kilometers.
Local Group of Galaxies
Consists of more than 50 galaxies.
Our Local Group is located in the outskirts of the Local Supercluster (also called Laniakea, Hawaiian for “immense heaven”).
Planet
A relatively small sphere of rock an/or gas that orbits a star
Star
A spherical ball of gas that generates its own energy(from nuclear reactions)
Moon(satellite)
An object that orbits a planet
Asteroid
A relatively small rocky object that orbits a star
Comet
A relatively small and ice-rich object that orbits a star
Star system
A star(can be more than one) and planets and objects that orbit it
