Which of the following best describes what we mean by the universe?
. the sum total of all matter and energy
a vast collection of stars that number as many as the grains of sand on all the beaches on Earth
our Milky Way Galaxy
all the galaxies in all the
Which of the following is a general difference between a planet and a star?
Planets are larger than stars.
. Stars glow in infrared and visible light, while planets glow only in the infrared.
Planets are brighter than stars.
All planets are made of rock a
Our solar system consists of
. the Sun and all the objects that orbit it
the Sun and several nearby stars, as well as the planets and other objects that orbit these stars
the Sun and the planets. and nothing else
a few hundred billion stars, bound togethe
What is nuclear fusion?
the process of splitting nuclei to produce energy
a process that only occurs in bombs
an explosion caused by putting together two volatile chemicals
the process of combining lightweight nuclei to make heavier nuclei
the process of
What do we mean when we say that the universe is expanding?
The statement is not meant to be literal; rather, it means that our knowledge of the universe is growing.
Within galaxies, average distances between star systems are increasing with time.
What do astronomers mean by the Big Bang?
. the event that marked the beginning of the expansion of the universe
the explosion of a massive star at the end of its life
a gigantic explosion that blew all the galaxies in the universe to smithereens
A television advertisement claiming that a product is lightyears ahead of its time does not make sense because
a light-year is an astronomically large unit, so a product could not possibly be so advanced
it doesn't specify the number of light-years
Earth is made mostly of metals and rocks. Where did this material come from?
It was made by our Sun.
It was made by nuclear ssion of uranium and other radioactive materials.
. It was produced by nuclear fusion in stars.
It was created by chemical reaction