1. __________________- Earth-centered

geocentric universe

Geocentric Theory

• The earth is the center of the universe.

• Proposed by Aristotle. He believed that the earth was the center of the universe and the five visible planets: Mercury, Venus, Mars, Jupiter and Saturn, and stars revolved around the earth.

• Five centuries later, Ptolemy updated Aristotle’s work. He determined that planets orbited Earth along circular paths, but would also follow a route around a smaller circle.

• Existed for more than 1,000 years.

2. __________________- sun-centered

(revised by __________)

heliocentric universe

Copernicus

1st proposed by Greek philosopher, 1st proposed by Greek philosopher, Aristarchus of Samos.Aristarchus of Samos.

Heliocentric Illustration

• Copernicus thought that the planets orbited the Sun, and that the Moon orbited Earth. The Sun, in the center of the universe, did not move, nor did the stars.

• Copernicus was correct about some things, but wrong about others. The Sun is not in the center of the universe, and it does move, as do the stars. Also, both Copernicus and Ptolemy thought the orbits of the planets were circular, but we now know they are elliptical.

3. ____________- the sun and all of its satellites

A. The sun contains _____% of all the mass in our solar system

Solar system

99.86

B. Johannes ______ discovered that the planets orbit the sun in ________ orbits.

Keplerelliptical

1) _________- closest

2) ________- farthest

perihelion aphelion

4. ________- an average middle-aged star that shines with yellow light

A. ____________- lowest layer of the sun’s atmosphere from which light is given off; surface- 6000º C.

B. _____________- from photosphere to about 2000 kmC. ________- above transition zone for millions of kilometers into space;

temps to 2,000,000 º C; seen during an aclipse

the sun

photosphere

chromosphere

corona

E. __________- charged particles that escape from the corona and move through spaceF. ________- darker, cooler spots on the sun’s surfaceG. ____________- huge, arching columns of gasH. ___________- violent eruptions from the sun that shoot gases outward at high speed

solar wind

sunspots

prominences

solar flares

5. Comets

B. Parts1)_______- rock and

ice core2) _____- the bright, halo-like

cloud that forms from vaporized gas

3) ____- gases that stream behind; always points ____ ____ the sun

A.Halley’s comet passes our sun every __ years76

nucleus

coma

tailaway

from

6. __________- doughnut-shaped region beyond Neptune where comets come from

Kuiper belt

7. ___________- a spherical region of comets that surrounds our solar system

Oort cloudOort cloud

8. ___________- fragments in space in no particular orbit

meteoroids

9. _________- space fragments that enter our atmosphere and burn up

meteors

10. ___________- meteors that hit Earth

meteorites

11. _________- particles caught between the inner and outer planets (Mars and Jupiter)

asteroids

* Ceres is the largest asteroid at 480 miles in diameter.