ASTR 150 Exam Questions with Verified Solutions Latest Update 2025/2026
Where are meteorites found on Earth? - Answers They fall uniformly on earth but we don't find
them uniformly because people look for them in specific places like Antarctica, which is dry and
stable. They are easily visible because of the meteorites dark color against the snow so most
are found there, the rest from other dry deserts.
Where do most meteorites come from? - Answers The outer part of the solar system!
What are meteorites made from? - Answers They come from the parent body (asteroids) and
are mostly rock (some have a little iron)
What are carbonaceous chondrites? - Answers A rare type of stony meteorite that includes
carbon and water. It has NOT gone under significant heating because it has lots of volatiles.
They are PRIMITIVE because they've never been changed since they were put together, meaning
the parent body never differentiated.
Carbonaceous parent bodies size? - Answers They are smaller than 10km in diameter, has been
small its whole life. We determine the age of things by determining the age of objects that have
never been heated (reset). We get the age of our solar system by the age of these primitive
meteorites!
what are ordinary chondrites? - Answers They have been heated and lack volatile elements but
haven't been heated enough to fully differentiate. They are barely younger than the solar system
so were heated very briefly and early on.
Asteroid age - Answers They all cooled almost immediately and are not geologically active, are
all ancient and the same age (4.4Byrs) except for carbonaceous chondrites.
For every 1 asteroid there are... - Answers 10 asteroids 1/3 its size
Asteroids are too small to... - Answers have atmospheres and geological activity. most are
potato shaped and crater covered.
At what age is an object in the solar system forced into a sphere? - Answers 500km or larger.
There's so much pressure they are forced into a sphere by gravity.
Most round objects in the SS are.. - Answers planets, Ceres (largest asteroid), or some satellites
what is the origin of the asteroid belt? - Answers Because there are carbonaceous chrondrites
that can't come from anything larger than 10km the belt was never one single world that broke
apart. Jupiter changes the orbits and velocities of asteroids in the belt, and high velocity means
accretion can't happen since objects will fragment. The asteroid belt is broken up because
they've never been able to build up and become larger
Mean motion resonance - Answers When 2 bodies have periods of revolution that are a simple
, integer ratio of each other (2:1, 3:!). Resonance changes orbits (Jupiter)
Achondrites - Answers Meteorites that are made of stony iron and iron. They have been
differentiated and come from worlds that were geologically active and larger than 100km. Also
4.4Byrs and lost heat immediately, They are the iron core of asteroids
Asteroid to asteroid belt ratio - Answers Asteroids are tiny compared to the space that
separates them. The asteroid belt is not crowded, usually 1.000.000km apart
Where is the asteroid belt? - Answers At the snow line, 3AU (from the sun) because that's where
ice and rock worlds form.
Most common solid material the solar system is built from - Answers Ice
Irregular satellites - Answers Are small (asteroid sized) and are regular in terms of shape, but
irregular in terms of orbit
Regular satellites - Answers Large and earth-moon sized, all are spherical. They have
synchronous rotation where the same face faces the planet at all times
Rings - Answers Small pieces of dust and ice orbiting the equator of a planet. All rings are within
the Roche Limit, and they are particles since they can't come together. Outside the roche limit is
when they come together and form regular satellites.
Tidal force - Answers The distance in gravity.
Roche limit - Answers The closer to a big object, the stronger the tidal force and more it wants
to be pulled further to be closer to the large things. O . . . At the dividing limit, the F gravity > F
tidal and the smaller objects are pulled towards each other. Outside the limit the objects are
pulled towards each other as well. Within the limit objects are pulled towards the big thing.
R roche = - Answers 2.5 R (radius) the planet
Thermal escape - Answers When the speed of a gas particle is greater than the escape velocity
of a world.
Escape velocity - Answers The minimum speed needed to escape the gravitational pull of a
planet. If something is faster than the orbital velocity it launches into space. Earth's escape
velocity is 11.2km/s (fast because Earth is large) Larger planet means more gravity means
higher V escape
Speed of a gas - Answers Depends on mass and temperature (distance from the sun). Bigger
mass is slower, higher temperature is faster.
Planets can hold onto a gas if the velocity of the gas is less than ___ - Answers 1/6 the escape
velocity of the planet. Ex) earth can't hold onto H2 and He since their velocity is larger than
Earth's escape velocity.
Where are meteorites found on Earth? - Answers They fall uniformly on earth but we don't find
them uniformly because people look for them in specific places like Antarctica, which is dry and
stable. They are easily visible because of the meteorites dark color against the snow so most
are found there, the rest from other dry deserts.
Where do most meteorites come from? - Answers The outer part of the solar system!
What are meteorites made from? - Answers They come from the parent body (asteroids) and
are mostly rock (some have a little iron)
What are carbonaceous chondrites? - Answers A rare type of stony meteorite that includes
carbon and water. It has NOT gone under significant heating because it has lots of volatiles.
They are PRIMITIVE because they've never been changed since they were put together, meaning
the parent body never differentiated.
Carbonaceous parent bodies size? - Answers They are smaller than 10km in diameter, has been
small its whole life. We determine the age of things by determining the age of objects that have
never been heated (reset). We get the age of our solar system by the age of these primitive
meteorites!
what are ordinary chondrites? - Answers They have been heated and lack volatile elements but
haven't been heated enough to fully differentiate. They are barely younger than the solar system
so were heated very briefly and early on.
Asteroid age - Answers They all cooled almost immediately and are not geologically active, are
all ancient and the same age (4.4Byrs) except for carbonaceous chondrites.
For every 1 asteroid there are... - Answers 10 asteroids 1/3 its size
Asteroids are too small to... - Answers have atmospheres and geological activity. most are
potato shaped and crater covered.
At what age is an object in the solar system forced into a sphere? - Answers 500km or larger.
There's so much pressure they are forced into a sphere by gravity.
Most round objects in the SS are.. - Answers planets, Ceres (largest asteroid), or some satellites
what is the origin of the asteroid belt? - Answers Because there are carbonaceous chrondrites
that can't come from anything larger than 10km the belt was never one single world that broke
apart. Jupiter changes the orbits and velocities of asteroids in the belt, and high velocity means
accretion can't happen since objects will fragment. The asteroid belt is broken up because
they've never been able to build up and become larger
Mean motion resonance - Answers When 2 bodies have periods of revolution that are a simple
, integer ratio of each other (2:1, 3:!). Resonance changes orbits (Jupiter)
Achondrites - Answers Meteorites that are made of stony iron and iron. They have been
differentiated and come from worlds that were geologically active and larger than 100km. Also
4.4Byrs and lost heat immediately, They are the iron core of asteroids
Asteroid to asteroid belt ratio - Answers Asteroids are tiny compared to the space that
separates them. The asteroid belt is not crowded, usually 1.000.000km apart
Where is the asteroid belt? - Answers At the snow line, 3AU (from the sun) because that's where
ice and rock worlds form.
Most common solid material the solar system is built from - Answers Ice
Irregular satellites - Answers Are small (asteroid sized) and are regular in terms of shape, but
irregular in terms of orbit
Regular satellites - Answers Large and earth-moon sized, all are spherical. They have
synchronous rotation where the same face faces the planet at all times
Rings - Answers Small pieces of dust and ice orbiting the equator of a planet. All rings are within
the Roche Limit, and they are particles since they can't come together. Outside the roche limit is
when they come together and form regular satellites.
Tidal force - Answers The distance in gravity.
Roche limit - Answers The closer to a big object, the stronger the tidal force and more it wants
to be pulled further to be closer to the large things. O . . . At the dividing limit, the F gravity > F
tidal and the smaller objects are pulled towards each other. Outside the limit the objects are
pulled towards each other as well. Within the limit objects are pulled towards the big thing.
R roche = - Answers 2.5 R (radius) the planet
Thermal escape - Answers When the speed of a gas particle is greater than the escape velocity
of a world.
Escape velocity - Answers The minimum speed needed to escape the gravitational pull of a
planet. If something is faster than the orbital velocity it launches into space. Earth's escape
velocity is 11.2km/s (fast because Earth is large) Larger planet means more gravity means
higher V escape
Speed of a gas - Answers Depends on mass and temperature (distance from the sun). Bigger
mass is slower, higher temperature is faster.
Planets can hold onto a gas if the velocity of the gas is less than ___ - Answers 1/6 the escape
velocity of the planet. Ex) earth can't hold onto H2 and He since their velocity is larger than
Earth's escape velocity.
