Astronomy Test 1

based on observations of the universal expansion, the age of the universe is

14 billion years

Which of the following correctly lists out Cosmic address from small to large?

Earth, solar system, Milky Way galaxy, local group, local supercluster, universe

could we see a galaxy that is 20 billion light-years away

No because it would be beyond the bounds of the observable universe

how long does it take for light to travel from the Sun to the Earth

about 8 minutes

A typical galaxy is a

collection of a few hundred million to a trillion or more stars, bound together by gravity

A tv ad claiming that a product is light-years ahead of its time does not make sense because

it uses light-years to talk about time, but a light-year is a unit of distance

our solar system consists of

the Sun and all the objects that orbit it

When we say that the universe is expanding, we mean that

the average distance between galaxies is growing with time

what do astronomers mean by the big bang

the event that marked the beginning of the expansion of the universe

The total number of stars in the observable universe is roughly equal to

the number of grans of sand on all the beaches on Earth

Which of the following best describes what we mean by the universe?

the sum of all matter and energy

The fact that nearly all galaxies are moving away from us, with the more distant ones moving faster, tells us that

the universe is expanding

The star Betelgeuse is 425 light-years away. If it explodes tonight,

we wont know about it until 425 years from now

if stars existed but galaxies did not,

we would not exist because we are made of material that was recycled in the galaxies