EM Spectrum, Light Years, Big Bang and Galaxies

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

• an asteroid belt
• a star system
• a galaxy
• a nebula

A scale diagram of four galaxies is provided. Which galaxy has a diameter closest to 75,000 light years?

• Galaxy JK23
• Galaxy TO37
• Galaxy RB17
• Galaxy WD28

To express the distance between the Milky Way galaxy and the Andromeda galaxy, the most appropriate unit of measure is the -

• miles
• kilometer
• light year
• astronomical unit

Proxima Centauri is the closest star to Earth after the Sun and is located 4.3 light years away from Earth. How long does it take light from Proxima Centauri to reach Earth?

• 1 year
• 4.3 years
• 43 years
• 10 trillion years

How many of the stars visible in the night sky are closer to Earth than to the Sun?

• All of them
• None of them
• About half
• Only one

The illustration provided shows four locations in or near the Milky Way Galaxy. Which of the labeled locations shows the approximate position of the Sun?

• W
• X
• Y
• Z

The stars and all the other matter in a galaxy are held together by which of the following?

• Dark matter
• Inertia
• Gravity
• Magnetism

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

• spiral
• elliptical
• irregular
• crescent

Composed of millions of stars as well as interstellar gas and dust -

• Galaxies
• Star
• Nebulae
• Black holes

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