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GS - Astronomy
Ch 22 - Origin of Modern Astronomy
Term | Definition |
---|---|
astronomy | Study of the universe |
geocentric | A model of the universe in which Earth is at the center of the revolving planets and stars. |
orbit | The curved path of a celestial object or spacecraft around a star |
heliocentric | A model of the solar system in which Earth and the other planets revolve around the sun |
Aristotle | (384-322 BC) philospher |
Eratosthenes | (276-194) An astronomer that is credited with being the first to establish the size of the Earth |
retrograde motion | The apparent motion of the planets when they appear to move backwards (westward) with respect to the stars from the direction that they move ordinarily. |
ellipse | A elongated circle |
astronomical unit | The average distance between Earth and the sun |
Aristarchus | (310?-250? BCE) Greek scientist who first stated that the Earth revolved around the Sun |
Claudius Ptolemy | ancient Greek astronomer that is known for his theory of an earth-centered universe |
Nicolas Copernicus | (1473-1543) concluded that the sun is the center of our solar system. Heliocentric Theory or Copernicus Theory. He wrote "On the Revolution of Heavenly Spheres" |
Tycho Brahe | (1546-1601) Established himself as Europe's foremost astronomer of his day; detailed observations of new star of 1572. |
Johannes Kepler | Assistant to Brahe; used Brahe's data to prove that the earth moved in an elliptical |
Galileo Galilei | 1564-1642 |
Sir Isaac Newton | Defined the laws of motion and universal gravitation and used them to predict the motion of stars and planets around the sun. |
rotation | CIRCULAR MOVEMENT AROUND AN AXIS |
revolution | Earth's yearlong elliptical orbit around the sun |
precession | A slow motion of Earth's axis that traces out a cone over a period of 26 |
perihelion | Nearest point to the sun in the orbit of a heavenly body |
aphelion | The place in the Earth's orbit where Earth is farthest away from the sun. |
perigee | Nearest point to the earth in the orbit of a heavenly body |
apogee | farthest point from the earth in the orbit of a heavenly body |
phases of the moon | the progression of changes in the moon's appearance during the month; |
solar eclipse | Occurs when the Moon passes directly between the Sun and Earth and casts a shadow over part of Earth |
lunar eclipse | Occurs whenever the Moon passes through the Earth's shadow |
crater | A large round pit caused by the impact of a meteoroid. |
ray | splash marks that radiate outwards from a crater |
mare | A large dark, relatively smooth area on the moon's surface |
rille | a long channel similar to valleys or trenches |
lunar regolith | a thin. gray layer on the surface of the moon |