Space I Unit

An object orbiting the sun disappeared behind the sun. A satellite did not detect the object. Astronomers thought it had been destroyed when it passed close to the sun. However, it was detected as a small, bright object with a fan-shaped tail. Astronomers proposed that the object was not destroyed. What type of object was most likely observed?

• A comet
• An asteroid
• A meteor
• A nebula

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

• Spectral Class O
• Spectral Class B
• Spectral Class A
• Spectral Class M

The Hertzsprung-Russell diagram shows how the sun is classified among the stars. A star that is several thousand times brighter that the sun with a temperature lower than 4000 K 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 K or M
• a white dwarf in spectral class B

The universe has many different components. Which list places four component of the universe in the most likely order from smallest to largest?

• planets, stars, galaxies, nebulae
• nebulae, stars, planets, galaxies
• galaxies, stars, planets, nebulae
• planets, stars, nebulae, galaxies

Two stars are identified on the H-R diagram below. Star 1 is a main sequence star, class O. Star 2 is a main sequence star, class F. Based on the diagram, how do the characteristics of Star 1 and Star 2 compare?

• Star 1 is cooler and less bright that Star 2
• Star 1 is hotter and brighter than Star 2
• Star 1 is cooler and brighter than Star 2
• Star 1 is hotter and less bright that Star 2

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

• A moon has less mass than a star and more mass than the planet it orbits.
• A Planet has less mass than a galaxy and more mass than the star it orbits.
• A galaxy has less mass than a moon and more mass than a planet.
• A star has less mass than a galaxy and more mass than a planet.

A Hertzsprung-Russell Diagram is shown. Based on this diagram, which type of stars would belong to a spectral class M and have the highest luminosity?

• Main-Sequence stars
• Giants
• White Dwarfs
• Super Giants

________ is a collection of dust and gasses that forms stars or results from dying stars.
______ is a sphere of matter with a density and a temperature great enough to cause a nuclear reaction at its center.

• star, supernova
• nebulae, supernova
• nebulae, star
• supernova, nebulae

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 part of this galaxy.
• Many more stars exist outside the galaxy.
• The stars in the center of the galaxy are extremely small.
• The center of the galaxy consists of a dense cluster of stars.

A student learns that the Sun is classified as a medium size star and that many stars are much brighter and bigger. However, the student observes that other stars look very dim, even through a telescope. Why do other stars look much dimmer that the sun?

• The Sun appears yellow, which is more visible than other colors.
• The Sun is much closer to Earth than other stars are.
• Other stars are mode up of differnt gasses than the sun is.
• As light from other stars trale thorugh space, it gets reflected.