Abeka 8th Grade Science, Section 10.1 Review

Explain why Copernicus's heliocentric system did not present an accurate picture of the solar system.

Copernicus incorrectly assumed that the planets' orbits were perfect circles and therefore had to add epicycles to the orbits.

Explain what gravity is and how it affects celestial objects.

Gravit is the force of attraction that exists between any two objects. The strong gravitational attraction between the large heavenly bodies holds the solar system together. This force also keep the planets in their elliptical orbits.

Who developed the three laws of planetary motion?

Johannes Kepler

What did Ptolemy teach about the structure of the universe?

The earth is at the center of the universe, with the sun, moon, and stars revolving around the earth. The apparent backward motion of the planets is explained by epicycles.

Which view of the solar system is currently accepted?

heliocentric

Define perihelion and aphelion.

perihelion - Earth's closest distance to the sun; aphelion - Earth's most distant point from the sun

Define astronomy.

the study of God's creation beyond our atmosphere

Define astronomical unit.

unit of length approximately equal to the distance between the earth and the sun