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