Earth Systems Notes
Ch. 22.1
Origin of Modern Astronomy
Early Astronomy
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_________________ is the science that studies the universe. It includes the
_________________and __________________________ of celestial bodies and phenomena.
The ___________________ used philosophical arguments to explain natural phenomena.
In the ancient Greeks’ _________________ model, the moon, sun, and the known planets—
Mercury, Venus, Mars, and Jupiter—orbit Earth.
In the ___________________model, Earth and the other planets orbit the sun.
_____________ created a model of the universe that accounted for the movement of the
planets.
____________________ motion is the apparent westward motion of the planets with respect
to the stars.
Birth of Modern Astronomy
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_____________________ ________________________ concluded that Earth is a planet. He
proposed a model of the solar system with the __________ at the center.
________________________ ____________________ designed and built instruments to
measure the locations of the heavenly bodies.
____________ discovered three laws of planetary motion:
1. Orbits of the planets are _____________.
2. Planets revolve around the sun at varying ____________.
3. There is a ___________________relationship between a planet’s orbital period and its
distance to the sun.
Kepler stated that planets move in an oval shaped path. An __________ is an oval-shaped path.
An __________________ _______________ (AU) is the average distance between Earth and
the sun; it is about 150 million kilometers.
____________ ______________’s most important contributions were his descriptions of the
behavior of moving objects.
He developed his own telescope and made important discoveries:
1. Four satellites, or ________, orbit Jupiter.
2. Planets are _______ disks, not just points of light.
3. ___________ has phases just like the moon.
4. The moon’s surface is not smooth.
5. The sun has _________________, or dark regions.
Sir Isaac Newton:
Although others had theorized the existence of gravitational force, _________ was the first to formulate
and test the law of ________________________ ________________________________.
_____________________ __________________ decreases with distance.
The greater the ____________ of an object, the greater is its _____________________ force.