UCLA ASTRO 5 FINAL EXAM QUESTIONS
WITH CORRECT ANSWERS
What formed the Sun and planets? - ANSWER Cloud of gas & dust
Why is the Solar System flat? - ANSWER Rotational forces in combination
with gravitational forces
What is the habitable zone? What defines it? - ANSWER 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? -
ANSWER 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? - ANSWER 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? - ANSWER ~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? - ANSWER ~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? - ANSWER 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? - ANSWER
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? - ANSWER 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? - ANSWER 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? - ANSWER 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? - ANSWER 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? - ANSWER 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 was the Cambrian Explosion? - ANSWER Fast increase in diversity of
species due to the rapid rise of oxygen. 540 MYA
WITH CORRECT ANSWERS
What formed the Sun and planets? - ANSWER Cloud of gas & dust
Why is the Solar System flat? - ANSWER Rotational forces in combination
with gravitational forces
What is the habitable zone? What defines it? - ANSWER 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? -
ANSWER 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? - ANSWER 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? - ANSWER ~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? - ANSWER ~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? - ANSWER 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? - ANSWER
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? - ANSWER 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? - ANSWER 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? - ANSWER 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? - ANSWER 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? - ANSWER 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 was the Cambrian Explosion? - ANSWER Fast increase in diversity of
species due to the rapid rise of oxygen. 540 MYA
