Universe PreAP

Which statement best describes a galaxy?

• A cloud of gas that is the birthplace of stars

• A system of billions of stars, gas, and dust held together by gravity

• A ball of plasma that experiences nuclear fusion in its core

• A mass of dust and ice that orbits a star in an elliptical pattern

Which statement about stars is correct?

• Supergiants are stars that can absorb black holes.

• White dwarfs become main sequence stars when they gain mass

• Main sequence stars are formed by comets

• Star formation begins in a nebula

Barnard's Star is about 5.9 light years from the Sun. The star has an approximate temperature of 2,800 Kelvins (K). Based on the chart, what spectral class does Barnard's Star belong to?

• Spectral Class O

• Spectral Class M

• Spectral Class A

• Spectral Class B

A star that is several thousand times brighter than the sun with a temperature lower than 4000K would be classified as.....

• a main sequence star in spectral class B

• a supergiant in spectral class K

• a main sequence star in spectral class M

• a white dwarf in spectral class B

The universe has many different components. Which list places four components in the correct order from smallest to largest?

• Galaxies, Nebulas, Stars, Planets

• Nebulas, Stars, Galaxies, Planets

• Planets, Nebulas, Stars, Galaxies

• Planets, Stars, Nebulas, Galaxies

Which of these correctly compares the masses of different objects in the universe?

• A galaxy has more mass than a nebula, and less mass than the Universe.

• A nebula has less mass than a star, and more mass than a galaxy.

• The universe has more mass than a galaxy, and less mass than a nebula.

• A moon has more mass than a planet it orbits, but less mass than a star.

Which of the following statements is true?

• White dwarfs are hotter and more luminous than main sequence stars.

• Supergiants are more luminous and hotter than white dwarfs.

• Main sequence stars increase in brightness as they increase in temperature.

• Giants are more luminous, but the same temperatures as supergiants.

Based on this diagram, which type of stars belong to spectral class O and have the highest luminosity?

• White Dwarfs

• Main sequence stars

• Giants

• Supergiants

Which of these observations of Procyon B is correct?

• Procyon B is brighter than the sun, has a surface temp below 5000 K, and is blue.

• Procyon B is dimmer than the sun, has a surface temp above 5000 K, and is red.

• Procyon B is brighter than the sun, has a surface temp below the sun's temp, and is white.

• Procyon B is brighter than the sun, has a surface temp above the sun's temp, and is white.

The Milky Way galaxy is described as a disk of stars orbiting a central point on the disk. Which of these best explains why people on Earth cannot see the entire shape of the Milky Way?

• Earth is a part of this galaxy.

• Many more stars exist outside of the galaxy.

• The stars at the center of the galaxy are extremely small.

• The center of the galaxy consists of a dense cluster of stars.