Solar System Flashcards
What does planet mean?
Wanderer
How can you tell a star from a planet?
Planets move around in the night sky while stars stay in the same spot.
Give two ways the sun effects the planets
By applying gravitational forces that keep the planet in orbit
Going through nuclear fusion and emitting that energy as light
Why was Pluto demoted?
It doesn’t have more mass than objects in nearby orbits.
It didn’t clear its space
What is an Astronomical Unit?
The measure of the distance from Earth to the sun= 1 AU
What are other planets’ AU compared to?
Why is Neptune 30 and Mercury’s less than 1?
They are compared to Earths distance
Neptune is 30x earth’s distance
Mercury is closer to the sun than earth is
What is the difference between an ellipse and a circle?
An ellipse is more oval like, or a stretched out circle
What is the accretion hypothesis?
It is a hypothesis on how the planets were formed
What does the accretion hypothesis state?
That the sun formed when gravity caused the solar nebula to collapse leading to particles that eventually formed into the planets
How did the inner planets form?
The inner planets formed from the accreted particles from the sun
How did the outer planets form?
They formed as gas, dust, and ice condensed and accreted
What condition must be met in order for a planet to have an atmosphere?
It has to have gravity strong enough to hold gases close to its surface
Why are the inner planets called “terrestrial planets”
You can walk on them
Why are the outer planets called gas giants
They are made of hydrogen and helium
What is a comet?
A object in space made out of ice rock and dust
What is a meteoroid?
A small rocky particle in space that burns up in earths atmosphere
What is a meteor?
A rocky particle that has a streak of light following it once it enters earths atmosphere
What is a meteorite?
A meteoroid that strikes a planet or moon
What is the true shape of a planetary orbit?
An ellipse
What does it mean if a planets orbit is highly eccentric?
It is very elliptical
What is eccentricity?
The measure of how elliptical a planets orbit is
What is the general term for a group of stars?
Constellation
What is parallax?
The apparent shift of an object when viewed from two locations
What is parallax used for?
To measure distances to stars
