AST 111 Study Questions Solved 100%
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According to current scientific estimates, when did the Big Bang occur? - ✔✔about 14 billion
years ago
On the cosmic calendar, which compresses the history of the universe into a single year, about
when did Earth form? - ✔✔in early September
On the cosmic calendar, which compresses the history of the universe into a single year, about
when did life arise on Earth? - ✔✔in september
On the cosmic calendar, which compresses the history of the universe into a single year, about
when did early humans first walk on Earth? - ✔✔just a few hours before midnight on
December 31
Which of the following statements best describes what astronomers mean when they say that
the universe is expanding? - ✔✔The average distance between galaxies is increasing with
time
Note that an observer located at the Local Raisin would see Raisins 1, 2, and 3 all move away
from her during the video. What would an observer located at Raisin 2 see? - ✔✔Raisin 1
and Raisin 3 both move away from her.
The table in the video shows you the speeds of Raisins 1, 2, and 3 as measured from the Local
Raisin. Suppose instead that you measured speeds as seen from Raisin 2. An observer at Raisin
2 would measure __________ - ✔✔Local Raisin speed = 4.0 cm/hr; Raisin 1 speed = 2.0
cm/hr; Raisin 3 speed = 2.0 cm/hr
,The following statements describe ways in which the analogy might apply to the real universe.
Which statements are correct? - ✔✔1. An observer at any raisin sees more distant raisins
moving away faster, just as an observer in any galaxy sees more distant galaxies moving away
faster.
2. The average distance increases with time both between raisins in the cake and between
galaxies in the universe.
3. The raisins stay roughly the same size as the cake expands, just as galaxies stay roughly the
same size as the universe expands.
Based on what you've learned from the raisin cake analogy, which two properties of distant
galaxies do astronomers have to measure to show that we live in an expanding universe? -
✔✔their distances and speeds
Today, the evidence that we live in an expanding universe is extremely strong because
astronomers have measured the motions of millions of galaxies. Nevertheless, in science, we
must always remain open to the possibility that some future observation could call even our
most strongly supported theories into question. Which of the following hypothetical
observations would not be consistent with what we expect in an expanding universe? -
✔✔You discover an extremely distant galaxy that is moving toward us.
Which of the following lies in the ecliptic plane? - ✔✔Earth's orbital path around the Sun
In January, Earth's rotation axis points in the direction of the star Polaris. Where does it point in
July? - ✔✔Toward the star Polaris
Match the words in the left-hand column to the appropriate blank in the sentences in the right-
hand column. Use each word only once - ✔✔1. Our entire solar system orbits around the
center of the Milky Way Galaxyabout once every 230 million years.
2. The Milky Way and Andromeda galaxies are among a few dozen galaxies that make up our
Local Group.
, 3. The Sun appears to rise and set in our sky because Earth rotatesonce each day.
4. You are one year older each time Earth orbitsabout the Sun.
5. On average, galaxies are getting farther apart with time, which is why we say our universeis
expanding.
6. Our solar systemis moving toward the star Vega at about 70,000 km/hr.
Shown here are astronomical objects located at different distances from Earth. Rank the
objects based on their distances from Earth, from farthest to nearest. - ✔✔FARTHEST: 1. star
on the far side of the andromita galexy,
2. star on the near side of the andromita galexy, star on the far side of the milkey way galexy,
star near the center of the milkey way galexy, oron nebula, Alpha Centrui, pluto, the sun
Consider again the objects you ranked by distance in Part A. Suppose each object emitted a
burst of light right now. Rank the objects from left to right based on the amount of time it
would take this light to reach Earth, from longest time to shortest time - ✔✔FARTHEST: 1.
star on the far side of the andromita galexy,
2. star on the near side of the andromita galexy, star on the far side of the milkey way galexy,
star near the center of the milkey way galexy, oron nebula, Alpha Centrui, pluto, the sun
Look once more at the objects you ranked in Parts A and B. This time, rank the objects from left
to right based on how much they have aged since they emitted the light we see today, from
greatest to least. - ✔✔FARTHEST: 1. star on the far side of the andromita galexy,
2. star on the near side of the andromita galexy, star on the far side of the milkey way galexy,
star near the center of the milkey way galexy, oron nebula, Alpha Centrui, pluto, the sun
Which of the following is not a general difference between a planet and a star? - ✔✔All
planets are made of rock and all stars are made of gas.
Our solar system consists of _________. - ✔✔the Sun and all the objects that orbit it