Terrestrial Planets Test

What collapses under the weight of it's own gravity?

a nebula

What forms after the nebula collapses?

a disk

What elements are found inside the disk?

carbon and iron

As the star forms, what does it eject?

extremely hot winds

What falls on the star while it's forming?

dust

What happens to some dust particles?

they clump together forming larger objects

What are the larger clumps called?

Planetesimals

What force causes the materials to collide?

Gravity

What happens if the collision is gentle enough?

fusion

What does the star do as fusion is happening?

it pulls in nearby gas and pushes away distant materials

What happens at places farther away from the sun?

Water freezes and dust particles pick up tiny fragments of ice

What does the frozen ice and dust particles form?

dirty snowballs

What are dirty snowballs used for?

planet cores

Which kind of planets formed this way?

Gas planets

What is the frost line?

The distance from the central protostar where it is cold enough for compounds to condense into solid grains

Where is the frost line currently?

At 5 AU in between the asteroid belt and jupiter

What is the purpose of the frost line?

to mark the separation between gas and terrestrial planets

What aspect of planets correlates to the distance from the sun?

density

what are terrestrial planets?

planets made up of rock or metals and have a hard surface

terrestrial planets form when...

materials closer to the sun get warmer than the materials farther away

what happens to the gases like water and ammonia?

they are broken apart or pushed outward by the solar winds

What do Kepler's Laws do?

they describe how the planets move around the sun, not why

Why do the planets move around the sun?

Because of gravity and newton's laws

What is Kepler's first law?

Planets orbit the sun in an elliptical orbit

What is Kepler's second law?

As a planet orbits the sun, a line from the planet to the sun sweeps across equal areas in equal times.

What is Kepler's third law?

The relationship between a planet's average distance from the Sun and time required for the planet to complete one orbit is inversely proportional

What is rotation?

an object's spinning motion about its own axis

What is revolution?

the mean time taken for one body, such as a planet, to complete a revolution about another, such as the sun

What is retrograde rotation?

Object that spins in the opposite direction of its orbit

Why is Venus Earth's evil twin?

Venus is similar to Earth in size, mass, density, and volume, but it has no surface water and the planet has a toxic, heavy atmosphere

What is the greenhouse effect?

Effect that occurs when gases in the atmosphere trap the Sun’s Heat

What are greenhouse gasses?

Gases in the atmosphere that trap heat.

What is special about Mercury's eccentric orbit?

It has the fastest period of revolution, and sometimes the sun doesn't rise or set

Which two planets are not visible at night?

Mercury and Venus