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One of the discoveries which led to the modern view of the solar system was that the orbits of the planets are _____.


First modern astronomer to propose a sun centered universe was ____.

Nicolaus Copernicus

This scientist determined the nature of the forces that kept the planets in their orbits.

Sir Isaac Newton

This scientist was the first to use the telescope in astronomy.


Three laws of planetary motion were discovered by ___.

Johannes Kepler

In the Ptolemaic (Greek) model of the universe, the ______.

Earth was in the center of the universe.

The apparent westward "drift" of the planets compared to the background stars is called____.

Retrograde motion

The belt of the constellations through which all the planets move is called the ___.


This astronomer spent 20 years plotting the position of the planet Mars.

Tycho Brahe

The true shape of the planetary orbits was discovered by ____.

Johannes Kepler

This astronomer is credited with "opening the door" to the era of modern astronomy.

Nicolaus Copernicus

Who formulated the law of universal gravitation?


The earth-centered system of the universe that was accepted for nearly 17 centuries was presented in a treatise called the Almagest that was written by ___.


The first successful attempt to establish the size of the earth is credited to ____.


Any variants in the orbit of a planet from its predicted path due to a gravitational pull is referred to as ___.


A very slow motion of earths axis that requires 26000 years to complete is called ____.


the apparent path of the sun upon the celestial sphere is called the ____.


In the Ptolemaic (Greek) model of the universe, the stars are attached to _____.

the celestial sphere

The length of daylight on the moon is about _______.

2 weeks

The period of time required for the moon to complete a cycle of phases is called the _____ month.


the period of time required for the moon to complete a revolution is called the _______ month.


One of the most common units used to express stellar distance is the _______.

light year

The measure of a star's brightness is the ____


The distance to stars can be determined by the _______.

stellar parallax

Our galaxy is called the _____.

milky way

Which colored stars have the highest surface temperature?


Which colored stars have the coolest surface temperature?


Which main sequence stars are the most massive?


Which main sequence stars are the least massive?


These stars are produced during a supernova event.

Black Hole

a star in which light cannot escape because of the immense gravitational pull at its surface is called a ______.

black hole

The final stage in evolution in the most massive stars is a _____.

black hole

The sun belongs to this class of stars.

main sequence

The point is stellar evolution when a star has used up all its fuel and is radiating away its remaining thermal energy as light is the _____.

white dwarf

Most stars are in this stage.

main sequence

The final stage for a star that is as massive as the sun is a ____.

black dwarf

When a main sequence star has exhausted the fuel in the inner regions it becomes a _________.

red giant

This property of a star can be determined from its color.

surface temperature

Hubble's law states that galaxies are receding from us at a speed that is proportional to their _____.


The discovery that the universe appears to be expanding led to a widely accepted theory called ___.

the Big Bang

Based on the observed red shifts in the spectral lines of distance galaxies, astronomers conclude that ______.

The universe is expanding.

A cluster of three large fresh looking impact craters shown in radar images of the surface of Venus best supports the conclusion that _____.

erosion and weathering are very slow processes on Venus

Which pair of solar system bodies comes closest to approximating a "double planet"?

Pluto and Charon

____ occurs when an object in the outer reaches of the solar system passes between earth and a far distant star, temporarily blocking light from the star.


Pluto is a _____.

dwarf planet

The _______ explains how our solar system probably formed from a giant cloud of gases and dispersed solid particles.

Nebular Hypothesis

_____ meteorites are thought to be analogous in composition to earth's core.


As the solar system was forming _________ came closest to an undergoing nuclear fusion and becoming a second sun.


Comets have highly ______ orbits around the Sun.


_____ has the great, dark spots on its surface.


Which of the following is not found on Mars?

Water in the atmosphere

How did the lunar maria most likely originate?

impact basins filled with basaltic lava

________ are found both on Mars and Earth.

erosional features related to flowing water

______, a moon orbiting Jupiter, has an unusually smooth, uncratered, icy surface.


The surface features of ______ are known only through satellite radar mapping.


Compared to the density of liquid water, the appropriate range in average densities of the terrestrial planets is _____.

4 to 6 g/cc

_____ has hot, turbulent atmosphere dominated by carbon dioxide.


Which lunar feature is the youngest?

brightly rayed craters

What is the principal gas in the Venusian atmosphere?

carbon dioxide

What is the largest known volcano in the solar system?

Mons Olympus

Which planet has a surface landscape similar to that of the older areas of the moon?




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