Exam 24: Stars, Space, and Galaxies

A concentration of older stars that shared a common origin and are held together by gravity, lying within the galactic halo of a spiral galaxy is called a(n) ____.

How far is a light-year?

All main-sequence stars are composed primarily of ____ and ____.

The ____ was the formation of helium nuclei by nuclear fusion during the first 8.5 minutes in the life of the Universe.

Astronomers believe that a ____ must lie at the center of our galaxy, the Milky Way.

What is a parsec?

The radiation emitted by stars, galaxies, and quasars is known as ____.

What powers the Sun?

What are main-sequence stars composed of primarily?

When we look at close objects, we see what is happening now, but when we look at distant objects, we see what happens in the future.

The cosmic background radiation is ____ radiation that began traveling through space when the Universe was about 300,000 years old.

Population II stars are originally composed of ____.

Neutron stars are ____.

How is all the information that we know about the Sun derived?

The cosmic microwave background radiation is an example of ____.

Which list correctly orders different regions of the Sun from highest temperature to lowest temperature?

The ____________________ zone is the inner part of a star surrounding the core where energy is transmitted by absorption and emission.

Describe a neutron star.

When was the first neutron star discovered?

Almost two-thirds of the bright galaxies in our region of the Universe, including the Milky Way, are ____.