Download Astronomy Study Guide CRCT Prep 1

Name____________________________________ Date______________________ Mr. Jones EARTH SCIENCE
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Unit One Study Guide – Astronomy – Universe and Solar System
It is very important to study and keep up with this study guide. All of this material will be covered and reviewed
throughout the year. Knowing this material will be essential to being successful on my test and ultimately the
CRCT.
 Scientific theories change when scientists discover new information.
 Prior to the 1500's it was believed that the earth was the center of the planets
(geocentric model). Copernicus first suggested the heliocentric system, where the sun is
at the center of the planets. With the use of telescopes, Galileo confirmed the
heliocentric system.
 The Big Bang Theory states that the universe formed about 10-15 billion years ago
through a huge explosion. The universe continues to expand rapidly.
 Our solar system is a single star system, but is located in the Milky Way Galaxy, which
contains other single stars, double stars, star systems, and dust and gas.
 The Milky Way Galaxy is one of billions of galaxies in the universe.
 The planets are divided into two groups. The inner planets are smaller, closer to the sun,
and have rocky surfaces, while the outer planets are larger, farther from the sun and do
not have solid surfaces.
 Inertia and gravity combine to keep the planets in orbit. The mass of an object and the
distance between objects determine the force of gravity.
 Comets, chunks of ice and dust, revolve around the sun with very, very elliptical orbits.
 Asteroids are smaller than planets and are found orbiting the Sun between Jupiter and
Mars.
 Meteoroids are a chuck of rock or dust found in space, and usually come from a comet
or asteroid.
 The stars are very, very far apart and only appear to lie close to one another because we
are so far from them.
 The gravitational attractions of the planets, either individually or as a group are so small
because of the distances between the planets that they cannot possibly have a
significant destructive effect on one another.
 The Big Bang is just one of several hypotheses that have been advanced to explain the
origin of the entire universe.
 Traveling to another planet would require very large amounts of money, planning, and
time, and would not be at all easy to do because of the expense and complexity of the
operation.
 Very low temperatures and the lack of water should make Mars a hostile planet for any
organism that has evolved in an Earth environment.
 The surface of Mars, like the surfaces of the other planets that we have observed
appears to have been sculpted by some of the same forces that shape the surface of
Earth (wind, moving liquids, meteorite and asteroid impacts, volcanic activity, and
seismic events.)
 Observational evidence caused the model of the solar system to be changed from one in
which the sun and planets orbit the Earth to one in which the Earth and planets orbit
the sun.
 The “Big Bang” is a theory of how the universe began.
 The sun is a medium-sized star located near the edge of a disk-shaped galaxy of stars
(Milky Way), part of which can be seen as a glowing band of light that spans the sky on a
very clear night.
 The planets of our solar system differ in size, composition (rock or gas), surface and
atmospheric features, and distance from the sun.
 Planets move around the sun in nearly circular orbits.
 The Earth is the only body in the solar system that appears to be able to support life.
 The motion of an object is always judged with respect to some other object or point, so
the idea of absolute motion or rest is misleading.
 Comets and asteroids are objects smaller than planets that orbit the sun and vary in
size, composition, and characteristics.
 Gravity is the force that keeps planets in orbit around the sun and governs the rest of
the motion in the solar system.
Essential Questions
1. How does the current model of the solar system differ from past models?
2. How does the Earth differ from the other planets?
3. Why does a star look different if you move from place to place?
4. How could you tell a planet from a star if you look at the same constellations over
several nights?
5. How are asteroids and comets different?