INTRODUCTION TO ASTRONOMY SNC 1D

ASTRONOMY Astronomy is the study of the universe and its contents. Ex. examining the atmosphere of Mars People who watch the stars and outer space and people who study astronomy are called astronomers.

ASTROLOGY Astrology is the study of the movements of celestial bodies (sun, stars, moon) interpreted in terms of their effects on human affairs. Ex. reading your horoscope

UNIVERSE The Universe comprises of everything we perceive to exist physically.

GALAXY A galaxy is a huge, rotating collection of stars, dust, planets, and other celestial objects within the universe. Our galaxy is the Milky Way containing more than billion stars.

CONSTELLATIONS A constellation is a group of stars in the sky that seem to form shapes that are recognized by humans.

STARS A star is a celestial body which gives off huge amounts of heat and light energy. They are luminous objects. (exception: black stars do not give off light).

SOLAR SYSTEM A solar system is made up of a sun and the objects (planets, moons, comets, and more) that orbit around it (travel around it).

PLANETS A planet is a nonluminous object that orbits a star (sun). The Earth and Mars are examples of planets.

MOONS A moon is a type of satellite: a celestial object that travels around a planet or dwarf planet.

ORBITS AND REVOLUTION The closed path of a celestial object or satellite as it travels around another, usually larger, celestial object is called an orbit. The time it takes for one orbit is the period of revolution or year.

ROTATION The time it takes for a celestial object to make one complete rotation around its axis is called the period of rotation or day

OUR PLACE IN THE UNIVERSE