Download Astronomy Chapters 22-24

Astronomy Chapters 22-24
Early Astronomy
• Astronomy is the study of the universe.
• Golden Age of astronomy centered in Greece
(600B.C. –A.D. 150).
• Aristotle concluded that earth was round
because saw round shadow of earth on
moon.
Early Astronomy
• Greeks believed in geocentric model of the
universe.
• “Geo” means Earth
• Geocentric model- the Earth was a sphere
that stayed motionless. The moon, sun, and
known planets- Mercury, Venus, Mars,
Jupiter- orbit the Earth.
Early Astronomy
• Later Aristarchus (312-230B.C.) was first to
believe in a sun-centered universe.
• “Helio” means sun
• Heliocentric model- Earth and other planets
orbit the sun.
Planetary Movement
Facts:
The orbit of each planet around the sun is an
eclipse or elliptical in shape.
A planet’s distance to the sun is expressed in
astronomical units or AUs.
An AU is the distance of the Earth to the sun,
about 150 million km.
Earth’s Moon
• The Giant Impact Hypothesis accounts for
origin of Earth’s moon.
• The Giant Impact HypothesisWhen solar system was forming, a body the
size of Mars struck Earth.
Ejected materials entered Earth’s orbit, forming
the Moon.
Formation of Solar System
• Nebular Theory- sun and planets formed
from a rotating disk of dust and gases
The Solar System
• The planets of our solar system are arranged
into 2 groups:
Terrestrial Planets and Jovian Planets
Terrestrial Planets- Mercury Venus, Earth, Mars
Jovian Planets- Jupiter, Saturn , Uranus, Neptune
Terrestrial Planets
Characteristics:
1. Smaller than Jovian Planets. Example Earth is ¼ size of Neptune.
2. Closer to the sun than Jovian planets.
3. Rockier than Jovian planets.
Terrestrial Planets
• Mercury- Innermost Planet, smallest
• Venus- Veiled Planet-”Earth’s twin”, active lava
flows
• Mars- the red planet, evidence of water has
been found on Mars, easiest to see
Jovian Planets- Gas Giants
• Jupiter- the Giant planet, 2 1/2 x mass of
other planets combined, hydrogen-helium
atmosphere, winds cause bands of color
• Saturn-the ringed planet, made of ice and
rock
• Uranus- the sideways planet, rotates on its
side
• Neptune- the windy planet