UCLA ASTRO 5 Final || With Errorless Answers.
What formed the Sun and planets? correct answers Cloud of gas & dust
Why is the Solar System flat? correct answers Rotational forces in combination with
gravitational forces
What is the habitable zone? What defines it? correct answers The habitable zone of the solar
system is where the temperature is right to be able to support life - not too close to the sun, not
too far away. The frost line defines the habitable zone.
Why are the inner planets rocky, while the outer planets are gaseous? correct answers The frost
line. The outer planets were formed first, and formed outside the frost line, so they had more
vitreous materials to create their planets from, and hydrogen ice. The inner planets had less
materials to work with and were formed inside the frost line with hydrogen vapor.
How was the moon formed? How do we know that? correct answers Moon was formed when a
competing planet crashed into the Earth during its formation, then got caught in our orbit. We
know this because Earth is the only rocky planet with a large moon and the materials on the
surface of the moon are the same as on Earth.
What was the Late Heavy Bombardment? Why was it both a good and bad thing for life on
Earth? correct answers ~4 BYA, period of intense asteroid and comets in the Solar System.
Wiped out any life Earth may have had at that time, but brought water, nitrogen atmosphere, and
possibly life.
When did life on Earth begin? What evidence to scientists use to determine this? correct answers
~3.8 BYA. Microfossils (fossils of anaerobic bacteria before rise of oxygen, ~3.4 BYA),
Stromatolites (colony of microbes that used photosynthesis ~3.5 BYA), Zircon Crystals (Not
direct evidence, but since need water could show life ~4.5 BYA)
, Why does it matter exactly when Earth began? correct answers Then we can make
determinations and more educated guesses about how life on Earth began - whether it was
created organically here, whether ingredients were brought here, or whether life itself was
delivered here.
What was the Miller-Urey experiment? What did we learn from it? correct answers Miller-Urey
experiment was an experiment done to see if molecules could form organically from scratch in
Earth's atmosphere. Although experiment wasn't perfect, through repeated trials we learned that
it could.
How did the first strands of RNA form? correct answers Ingredients came together in the mud of
shallow ponds to form RNA.The bases stick to the mud/clay and then find each other to form
strands.
How did the first cells form? correct answers The RNA strands were trapped in a pre-cell/vesicle
and go through evolution of self replication. From here, DNA evolves from RNA to form a true
cell.
What are three ways life on Earth could have started? correct answers Life was formed from
scratch on Earth, ingredients for life were delivered to Earth by a comet or asteroid, life itself
was delivered here.
What is panspermia? What evidence do we have that panspermia is possible in our Solar
System? correct answers Panspermia is the theory that life can spread throughout the solar
system between different planets. Evidence we have is that Mars probably once had life, and we
know that materials from Mars have landed on Earth before. Also, tardigrades and other
extremophiles.
What caused the rapid rise of oxygen in our atmosphere? correct answers The rise of
cyanobacteria led to the rise of oxygen. The oxygen levels rose when the oxygen sinks filled up
and could no longer contain the oxygen. It was then released into the atmosphere.
What formed the Sun and planets? correct answers Cloud of gas & dust
Why is the Solar System flat? correct answers Rotational forces in combination with
gravitational forces
What is the habitable zone? What defines it? correct answers The habitable zone of the solar
system is where the temperature is right to be able to support life - not too close to the sun, not
too far away. The frost line defines the habitable zone.
Why are the inner planets rocky, while the outer planets are gaseous? correct answers The frost
line. The outer planets were formed first, and formed outside the frost line, so they had more
vitreous materials to create their planets from, and hydrogen ice. The inner planets had less
materials to work with and were formed inside the frost line with hydrogen vapor.
How was the moon formed? How do we know that? correct answers Moon was formed when a
competing planet crashed into the Earth during its formation, then got caught in our orbit. We
know this because Earth is the only rocky planet with a large moon and the materials on the
surface of the moon are the same as on Earth.
What was the Late Heavy Bombardment? Why was it both a good and bad thing for life on
Earth? correct answers ~4 BYA, period of intense asteroid and comets in the Solar System.
Wiped out any life Earth may have had at that time, but brought water, nitrogen atmosphere, and
possibly life.
When did life on Earth begin? What evidence to scientists use to determine this? correct answers
~3.8 BYA. Microfossils (fossils of anaerobic bacteria before rise of oxygen, ~3.4 BYA),
Stromatolites (colony of microbes that used photosynthesis ~3.5 BYA), Zircon Crystals (Not
direct evidence, but since need water could show life ~4.5 BYA)
, Why does it matter exactly when Earth began? correct answers Then we can make
determinations and more educated guesses about how life on Earth began - whether it was
created organically here, whether ingredients were brought here, or whether life itself was
delivered here.
What was the Miller-Urey experiment? What did we learn from it? correct answers Miller-Urey
experiment was an experiment done to see if molecules could form organically from scratch in
Earth's atmosphere. Although experiment wasn't perfect, through repeated trials we learned that
it could.
How did the first strands of RNA form? correct answers Ingredients came together in the mud of
shallow ponds to form RNA.The bases stick to the mud/clay and then find each other to form
strands.
How did the first cells form? correct answers The RNA strands were trapped in a pre-cell/vesicle
and go through evolution of self replication. From here, DNA evolves from RNA to form a true
cell.
What are three ways life on Earth could have started? correct answers Life was formed from
scratch on Earth, ingredients for life were delivered to Earth by a comet or asteroid, life itself
was delivered here.
What is panspermia? What evidence do we have that panspermia is possible in our Solar
System? correct answers Panspermia is the theory that life can spread throughout the solar
system between different planets. Evidence we have is that Mars probably once had life, and we
know that materials from Mars have landed on Earth before. Also, tardigrades and other
extremophiles.
What caused the rapid rise of oxygen in our atmosphere? correct answers The rise of
cyanobacteria led to the rise of oxygen. The oxygen levels rose when the oxygen sinks filled up
and could no longer contain the oxygen. It was then released into the atmosphere.
