Which of the following best describes a star?  A star is a celestial body ---

• composed of rock and metal with a very high density
• that is too big to be an asteroid, but too small to be a planet.
• that rotates on an axis and revolves around the Sun
• composed of gases that emit light due to nuclear reactions

Which of the following best describes a nebula.  A nebula is

• a region in the solar system that is occupied by irregularly shaped bodies
• a large and icy celestial body with an irregular orbit around the Sun
• a natural satellite created by the collision of two large asteroids
• an interstellar cloud of dust, hydrogen, helium and other gases

Which of the following best describes a galaxy?  A galaxy is ---

• A particle of debris in the solar system that does not act as a satellite of any planet
• a visible body of liquid or frozen crystal droplets suspended above a planetary surface
• a massive system of stars, gas, dust and dark matter bound together by gravity.
• the visible path of a meteoroid as it enters Earth's atmosphere

Use the Hertrzsprung-Russell diagram to answer the following question.  A trend among the Main Sequence Stars is that

• most of the stars are white or red
• the hotter the star, the more brightly it burns
• stars dimmer than the sun are of Blue
• the larger stars emit light that is blue

An interstellar cloud of dust and gases that serves as a location for the formation of new stars is

• a meteor
• a planet
• a galaxy
• a nebula

Galaxies are classified into all of the following types by their shapes except --

• spiral
• elliptical
• lenticular
• crescent

Which of the following is an accurate description of the relationship between components of the universe?

• Stars always contain galaxies
• Galaxies contain many stars
• Stars contain several nebulae
• Nebulae contain many galaxies

A characteristic of a nebula is that it

• is at the center of the solar system
• is a region where stars are born
• forms halfway through a star's life cycle
• has the coolest temperature in space

Use the Hertzsprung-Russell Diagram to answer the following question.  Regulus belongs in which of the following classifications

• Super Giants
• Giants
• Main Sequence Stars
• White Dwarfs

Which of the following components of the universe is best described as a system of stars, gases, and dust held together by gravity.

• a nebula
• a planet
• a meteor
• a galaxy