ASTRONOMY 101
EXAM 1 - Lifan Wang
Why can't we see a galaxy 15 billion light-years away? (Assume the universe is 14
billion years old.)
A. No galaxies exist at such a great distance.
B. Galaxies may exist at that distance, but their light would be too faint for our
telescopes to see.
C. Looking 15 billion light-years away means looking to a time before the universe
existed.
Let's reduce the size of the solar system by a factor of 10 billion; the Sun is now
the size of a large grapefruit (14 cm diameter). How big is Earth on this scale?
A. an atom
B. a tip of a ballpoint pen
C. a marble
D. a golf ball
,On our 1-to-10 billion scale, it's just a few minutes' walk to Pluto. How far would
you have to walk to reach Alpha Centauri?
A. 1 mile
B. 10 miles
C. 100 miles
D. the distance across the United States (2500 miles)
How big is the Milky Way Galaxy?
The Milky Way has about 100 billion stars.
Suppose you tried to count the more than 100billion stars in our galaxy, at a rate
of one per second...How long would it take you?
A. a few weeks
B. a few months
C. a few years
D. a few thousand years
What is our place in the Universe?
, Earth is part of the solar system, which is in the Milky Way Galaxy, which is a
member of the Local Group of galaxies in the Local Supercluster
How big is the Universe?
The observable universe dwarfs our Milky Way Galaxy, which in turn dwarfs our
solar system. Scale models can help with visualizing such distances.
How do our lifetimes compare to the age of the universe?
The cosmic calendar: A scale on which we compress the history of the universe
into 1 year
How did we come to be?
The matter in our bodies came from the Big Bang, which produced hydrogen and
helium.- - All other elements were constructed from H and He instars and then
recycled into new star systems, including our solar system.
How do our lifetimes compare to the age of the universe?
On a cosmic calendar that compresses the history of the universe into 1 year,
human civilization is just a few seconds old, and a human lifetime is a fraction of a
second.
EXAM 1 - Lifan Wang
Why can't we see a galaxy 15 billion light-years away? (Assume the universe is 14
billion years old.)
A. No galaxies exist at such a great distance.
B. Galaxies may exist at that distance, but their light would be too faint for our
telescopes to see.
C. Looking 15 billion light-years away means looking to a time before the universe
existed.
Let's reduce the size of the solar system by a factor of 10 billion; the Sun is now
the size of a large grapefruit (14 cm diameter). How big is Earth on this scale?
A. an atom
B. a tip of a ballpoint pen
C. a marble
D. a golf ball
,On our 1-to-10 billion scale, it's just a few minutes' walk to Pluto. How far would
you have to walk to reach Alpha Centauri?
A. 1 mile
B. 10 miles
C. 100 miles
D. the distance across the United States (2500 miles)
How big is the Milky Way Galaxy?
The Milky Way has about 100 billion stars.
Suppose you tried to count the more than 100billion stars in our galaxy, at a rate
of one per second...How long would it take you?
A. a few weeks
B. a few months
C. a few years
D. a few thousand years
What is our place in the Universe?
, Earth is part of the solar system, which is in the Milky Way Galaxy, which is a
member of the Local Group of galaxies in the Local Supercluster
How big is the Universe?
The observable universe dwarfs our Milky Way Galaxy, which in turn dwarfs our
solar system. Scale models can help with visualizing such distances.
How do our lifetimes compare to the age of the universe?
The cosmic calendar: A scale on which we compress the history of the universe
into 1 year
How did we come to be?
The matter in our bodies came from the Big Bang, which produced hydrogen and
helium.- - All other elements were constructed from H and He instars and then
recycled into new star systems, including our solar system.
How do our lifetimes compare to the age of the universe?
On a cosmic calendar that compresses the history of the universe into 1 year,
human civilization is just a few seconds old, and a human lifetime is a fraction of a
second.
