LATEST UPDATE 2026
Which of the following is NOT a general difference between a planet and a star?
A. Planets are smaller than stars.
B. Planets are dimmer than stars.
C. All planets are made of rock and all stars are made of gas.
D. Planets orbit stars, while stars orbit the center of the galaxy. - Answers C. All
planets are made of rock and all stars are made of gas.
Our solar system consists of _________.
A. the Sun and several nearby stars, as well as the planets and other objects that orbit
these stars
B. the Sun and all the objects that orbit it
C. a few hundred billion stars, bound together by gravity
D. the Sun and the nine planets, and nothing else - Answers B. the Sun and all the
objects that orbit it
A typical galaxy is a _________.
A. system consisting of one or a few stars orbited by planets, moons, and smaller
objects
B. nearby object orbiting a planet
C. large, glowing ball of gas-powered by nuclear energy
D. collection of a few hundred million to a trillion or more stars bound together by
gravity
E. relatively small, an icy object orbiting a star - Answers D. collection of a few
hundred million to a trillion or more stars bound together by gravity
Which of the following best describes what we mean by the universe?
A. A vast collection of stars that number as many as the grains of sand on all the
beaches on Earth
B. All the galaxies in all the superclusters
C. The sum total of all mater and energy
D. The universe is another name for our Milky Way Galaxy. - Answers C. The sum
total of all mater and energy
What do astronomers mean by the Big Bang?
A. The event that marked the beginning of the expansion of the universe
, B. The explosion of a massive star at the end of its life
C. A gigantic explosion that blew all the galaxies in the universe to smithereens
D. The event that marked the birth of our solar system - Answers A. The event that
marked the beginning of the expansion of the universe
What do we mean when we say that the universe is expanding?
A. Everything in the universe is gradually growing in size.
B. The statement is not meant to be literal; rather, it means that our knowledge of the
universe is growing.
C. Average distances between galaxies are increasing.
D. Average distances are increasing between star systems within galaxies - Answers
C. Average distances between galaxies are increasing.
Based on observaTions of the universal expansion, the age of the universe is about
A. 14,000 years
B. 14 trillion years
C. 14 billion years
D. 14 million years - Answers C. 14 billion years
A television advertisement claiming that a product is light-years ahead of its time
does not make sense because of _________.
A. a light-year is an astronomically large unit, so a product could not possibly be so
advanced
B. light-years can only be used to talk about light
C. it uses "light-years" to talk about time, but a light-year is a unit of distance
D. it doesn't specify the number of light-years - Answers C. it uses "light-years" to
talk about time, but a light-year is a unit of distance
The term observable universe refers to _________.
A. the portion of the universe that is not hidden from view by, for example, being
below the horizon
B. that portion of the universe that we have so far photographed through telescopes
C. the portion of the universe that can be seen by the naked eye
D. that portion of the universe that we can see in principle, given the finite age of the
universe - Answers D. that portion of the universe that we can see in principle, given
the finite age of the universe
On a scale in which the distance from the Sun to the Earth is about 15 meters, the
distance from the Earth to the Moon is _________.