ASTR 104 – Winter 2008 Intersession – Final Exam
Questions on material that we have not covered are greyed out. Blue questions refer to test 3 material.
(1) Why do stars twinkle?
a. Because they are burning spheres of hot gas.
b. Because of their slow motion across the sky.
c. Because of the scattering of starlight caused by Earth's atmosphere.
d. Because sometimes one of their planets passes in front of them.
(2) Does any object rise in the West and set in the East at night?
a. Yes, some stars, called retrograde stars, do.
b. Yes, planets do when they are in retrograde motion.
c. No, celestial objects other than the Sun and Moon do not rise and set.
d. No, celestial objects always rise in the East and set in the West.
(3) What part of the world do we trace the earliest attempts to understand
and make models of the Solar System to?
a. Mexico and Central America.
b. Greece and the Middle East.
c. Northern Europe.
d. Southern Africa.
(4) Which of these is the main contribution to astronomy by Tycho Brahe?
a. He made excellent observations of the planets' positions.
b. He proposed a modern heliocentric model of the solar system.
c. He explained the orbits of planets in terms of gravity.
d. He was the first person to use a telescope in astronomy.
(5) Why does an object weigh less on the Moon than on Earth?
a. Because the Moon is very far from the center of the Earth.
b. Because the mass of the object is smaller on the Moon.
c. Because the force of gravity is weaker on the Moon.
d. Because the Moon has no atmosphere.
(6) Which of these types of waves has the longest wavelength?
a. Gamma rays.
b. Visible light.
c. Microwaves.
d. Radio waves.
(7) How many stars does the Solar System contain?
a. None.
b. One.
c. Several thousands.
d. About 100 billion.
(8) What is interesting about the middle star of the handle in the Big
Dipper, Mizar?
a. It is a binary star.
b. It is a supergiant star.
c. It is the fastest moving star.
d. It is the brightest star in the sky.
(9) What percentage of its life does a star spend on the main
sequence?
a. 10%.
b. 50%.
c. 90%.
d. It varies, some stars never get to the main sequence, other
stars never leave it.
(10) Why do astronomers look for supernova explosions in distant
galaxies?
a. Because they hope to see signs of life starting to form
after the explosion.
b. Because seeing a supernova allows them to find the distance
to the galaxy.
c. Because it is interesting to see what happens when a whole
galaxy is blown away.
d. Because they are puzzled by the fact that so far they
have only been seen in our galaxy.
(11) How massive are neutron stars, compared to the Sun?
a. About 8% of the Sun's mass.
b. About 1.4 to 3 solar masses.
c. About 100 solar masses.
d. Between 0.08 and 100 solar masses.
(12) Which one of the following is a way for black holes
to form?
a. A star is surrounded by so much dust that no light
can shine through.
b. A star is formed from a cloud of dark matter instead
of regular matter.
c. A star collapses to such a small size that its gravity
prevents light from escaping.
d. A star cools down past the white dwarf stage and in
the end emits no light at all.
(13) What is the most common element in interstellar
space?
a. Helium.
b. Carbon.
c. Oxygen.
d. Hydrogen.
(14) Why are certain nebulae dark?
a. Because they are outside our galaxy.
b. Because they are cold and thick, and starlight cannot
go through them.
c. Because they have become black holes.
d. Because they are made of a very thin gas which
has no effect on light.
(15) What part of our galaxy are we located in?
a. The disk.
b. The halo.
c. The core.
d. The bulge.
(16) Which of the following is not one of the main
types of galaxies?
a. Spiral galaxy.
b. Elliptical galaxy.
c. Globular galaxy.
d. Irregular galaxy.
(17) Do supernovas occur with single or binary
stars?
a. Neither, they have to be in larger clusters.
b. Either one, there are two different types.
c. Single stars.
d. Binary stars.
(18) Which color of light passes more easily
through dust in space?
a. Red.
b. Blue.
c. Green.
d. All colors are dimmed by the same amount.
(19) What do we believe is at the center
of the Milky Way?
a. We don't have enough information to
make a guess.
b. A giant nebula containing 100 billion
stars.
c. A black hole of more than two million
solar masses.
d. A globular cluster or a supermassive
galaxy.
(20) Why do stars swell up to much larger
sizes after the main sequence stage in
their lives?
a. Because the core grows in size and
pushes the other layers outwards.
b. Because what makes them leave the
main sequence is often a violent collision.
c. Because the temperature and rate of
energy production in the core increase.
d. Because the core shrinks, the layer
around it contracts, and it becomes hotter.
(21) What is the Milky Way?
a. A bright reflection nebula contained
in the Large Magellanic Cloud.
b. The path followed by the Sun in
its motion around the galactic center.
c. The galaxy that the Solar System
and the stars around us are located
in.
d. A distant galaxy which can be seen
in the constellation of Sagittarius.
(22) The speed of light is 300,000
km/s. A spaceship is moving in your
direction
at 100,000
km/s while
you are
moving away
at 150,000
km/s.
If the spaceship
shines a beam of light at you, how
fast will you see the beam of light
moving?
a. 50,000 km/s.
b. 150,000 km/s.
c. 300,000 km/s.
d. 400,000 km/s.
(23) What effect can the shock wave
from a supernova explosion have
in interstellar
space?
a. It can cause a star to collapse
and form a black hole.
b. It can trigger the sudden explosion
of another massive star.
c. It can trigger star formation
in a molecular cloud by compressing
it.
d. It can produce a nova by heating
up the accretion disk around a
white dwarf.
(24) When you look at the sky at
night, are the stars you see
with the naked
eye inside
our own
galaxy?
a. Yes, all of them are inside
our galaxy.
b. No, each of those stars is
inside its own galaxy.
c. Some of them are, but most
belong to different galaxies.
d. No, stars are not actually
inside the galaxy, they orbit
around it.
(25) Does the Sun orbit around
anything?
a. No, planets orbit around
the Sun.
b. Yes, the Earth.
c. Yes, the center of our galaxy.
d. Yes, the center of the universe.
(26) Why are right ascension
and declination better than
altitude and azimuth for
specifying the location
of a
star?
a. Because right ascension
and declination can be predicted
more accurately.
b. Because right ascension
and declination take the
star's parallax
into account.
c. Because altitude and azimuth
change with the location
on Earth and in
time.
d. Because altitude and azimuth
are old-fashioned and their
meaning is
not very clear.
(27) How hot are the surfaces
of the hottest stars, approximately?
a. 300 K.
b. 5000 K.
c. 50,000 K.
d. 200 million K.
(28) How did people first
figure out how far the
Andromeda galaxy
is?
a. By spotting bright
Cepheid variable stars
in it.
b. By watching a supernova
explosion inside it.
c. By using the parallax
method and the HR diagram.
d. By finding its velocity
and using Hubble's law.
(29) What does the angular
resolution tell you
about a telescope?
a. Its ability to detect
fine detail and produce
sharp images.
b. The number of spectral
lines one can see with
it.
c. Its ability to produce
bright images of faint
objects.
d. The magnification
of the images it produces.
(30) If a star is 10,000
light years away,
which one of the
following could it
possible belong
to?
a. The Solar System.
b. The Milky Way
Galaxy.
c. The Andromeda
Galaxy.
d. The Virgo Cluster.
(31) As we observe
beyond a certain
distance from
us, we
start to
see no more galaxies.
How is this
possible?
a. There are too
many clouds of
gas and dust
in between.
b. We are looking
back in time to
when galaxies
first
started
forming.
c. Beyond that
distance all galaxies
become
too faint.
d. Beyond that
distance there
is just empty
space with
no more galaxies.
(32) Why didn't
ancient astronomers
see parallax
for the stars?
a. Because the
Earth's motion
prevents us
from seeing the
parallax.
b. Because stars
are so distant
that one
needs a telescope
to see their
parallax.
c. Because they
incorrectly thought
that they
were seeing retrograde
motion instead.
d. Because they
didn't know that
one can
see parallax
only on
certain days
of the
year.
(33) Approximately
how far from
us is the Andromeda
galaxy, M31?
a. 2 light
years.
b. 2,000 light
years.
c. 2 million
light years.
d. 2 billion
light years.
(34) Approximately
how long
does it take for
our galaxy
to rotate
once?
a. About
2,200 years.
b. About
100,000 years.
c. About
220 million
years.
d. About
10 billion
years.
(35) According
to Kepler's
laws, the
orbit of
a planet
is:
a. A perfect
circle,
with the
Sun at
the center.
b. An ellipse,
with the
Sun at
the center.
c. A circle,
with smaller
circles
added in
to account
for
detailed
observations.
d. An ellipse,
with the
Sun at
one of
the foci.
(36) What
are the
Magellanic
Clouds?
a. Large
clouds
of gas
and
dust
near
the center
of the
Milky
Way.
b. Smaller
clouds
of dust
near
the Trapezium
inside
the Orion
nebula.
c. Two
small
irregular
galaxies
near
the Milky
Way.
d. The
two largest
galaxies
in the
Local
Group.
(37)
Where
is
the center
of
the
universe?
a.
At
the
center
of
the
Milky
Way.
b.
Near
the
middle
of
the
Virgo
cluster
of
galaxies.
c.
We
don't
know
exactly,
but
somewhere
near
the
Great
Attractor.
d.
There
is
no
center,
if
our
current
ideas
are
correct.
(38)
What
happens
inside
an
atom
when
it
absorbs
a
photon?
a.
The
nucleus
becomes
hotter
and
expands.
b.
An
electron
jumps
from
a
lower
energy
state
to
a
higher
one.
c.
One
more
electron
is
added
to
the
atom.
d.
All
electrons
start
moving
faster
along
their
orbits.
(39)
Do planets
affect the
motion of
their stars?
a.
Yes, planets
slow down
the motion
of their
stars around
the galaxy.
b.
Yes, stars
also feel
a gravitational
pull from
planets, but
move much
less.
c.
No, it
is the
other way
around, stars
make the
planets go
around in
orbits.
d.
No, stars
only move
in orbits
around the
center of
the galaxy.
(40)
Why did
ordinary atoms
form only
many years
after the
Big Bang?
a.
Because before
then there
was no
matter in
the universe.
b.
Because it
took that
long for
the universe
to cool
down enough.
c.
Because before
then protons
and electrons
repelled each
other.
d.
Because stars
are needed
for atoms
to be
able to
form.
(41)
If a
thin gas
is heated
to thousands
of degrees,
one obtains
from it
a.
An emission
line spectrum.
b.
An absorption
line spectrum.
c.
A continuous
emission spectrum.
d.
A continuous
absorption spectrum.
(42)
What is
the main
evidence we
have that
the universe
started with
a hot
big bang?
a.
The cosmic
microwave background.
b.
The presence
of dark
matter.
c.
The age
of globular
clusters in
our galaxy.
d.
The fact
that the
cores of
many galaxies
are still
burning.
(43)
What is
Olbers' paradox?
a.
The fact
that the
night sky
is dark
rather than
bright.
b.
The fact
that the
universe is
still expanding
after so
long.
c.
The fact
that there
is so
much dark
matter in
the universe.
d.
The fact
that such
a large
universe could
have come
from a
point.
(44)
How do
the planets
in the
outer Solar
System compare
to Earth?
a.
They all
orbit around
the Sun
in the
opposite direction.
b.
Them are
all much
larger than
the Earth.
c.
They are
all smaller
than the
Earth.
d.
They are
about the
same size,
but they
have rings
instead of
a moon.
(45)
How are
people trying
to find
out if
extrasolar
planets
have atmospheres?
a.
Measure
the
rotation
of
the planet.
b.
Look for
a Doppler
shift in
light coming
from the
planet.
c.
Measure
the
mass of
the planet.
d.
Look for
absorption
lines
in starlight
passing
near
the planet.
(46)
How many
extrasolar
planets
have we
discovered
so
far?
a.
None, but
technology
will
soon reach
a point
where we
will find
them.
b.
Two,
they
have
just
been
discovered
last
year
by
the
Hubble
Telescope.
c.
More
than
200
have
been
reported,
and
the
list
keeps
growing.
d.
Thousands;
every
star
that
has
been
carefully
checked
has
planets.
(47)
By how
much
do
stars move
on the
celestial
sphere
over
time?
a.
They
move
about
a
degree
per
day,
that
is
why
summer
and
winter
constellations
are
different.
b.
They
are
constantly
moving,
that
is
why
they
rise
in
the
East
and
set
in
the
West
every
day.
c.
They
hardly
move,
at
most
by
a
few
arcsecond
per
year,
and
usually
it
takes
years
to
notice.
d.
Stars
do
not
move
on
the
celestial
sphere,
only
planets
do.
(48)
How
long
after
the
Big
Bang
did
the
first
stars
and
galaxies
form?
a.
Three
minutes.
b.
300,000
years.
c.
Several
hundred
million
years.
d.
13.7
billion
years.
(49)
How
can
we
find
neutron
stars?
a.
If
they
are
not
surrounded
by
glowing
matter
there
is
no
way
for us
to
see
them.
b.
They
can
often
be
seen
as
pulsars,
from
which
we
get
pulses
of radio
waves.
c.
We
recognize
them
because
they
shine
more
brightly
than
any
other
regular
star.
d.
We
look
for
stars
whose
brightness
changes
over
a
period
of
a
few days.
(50)
How
many
stars
do
open
clusters
usually
have?
a.
Between
2
and
5.
b.
A
dozen
or
so.
c.
A
few
hundreds
or
thousands.
d.
Hundreds
of
thousands
or
more.
(51) What is an epicycle?
(52) What is the Big Bang?
(53) How can we find the distance to the nearest stars?
(54) Explain very briefly one method that has been successful in the search
for extrasolar planets.
(55) What is the Local Group?
(56) Name one prediction of Einstein’s theory of gravity that was not
part of Newton’s theory of gravity.
(57) What is a galaxy?
(58) What is a nebula?
(59) Do the objects in the room around you emit any radiation? (If yes, what
type? If no, how do you know?)
(60) What is the solution of Olbers’ paradox?
(61) A 2007 TV news report said that "Pictures of the star Mira, a red
giant similar to what the Sun will be like near the end of its life, have shown
that it has a tail, several light-years long, of material it has been ejecting
over many thousands of years while moving across a distant galaxy". What
is wrong with the statement?