Mass & Gravity
The bigger a planet’s mass, the ______ its gravitational pull.
Stronger
A planet’s YEAR is the time it takes the planet to ______.
Travel all the way around the sun once
What does AU stand for?
Astronomical Unit
What is a nebula?
A cloud of gas and dust in space
Which kind of planet is small, rocky, and found close to the Sun?
Terrestrial Planet
Planet Zed has less mass than Earth. Compared to Earth, its gravity is ______.
Weaker
A planet’s DAY is the time it takes the planet to ______.
spin once on its own axis
1 AU is the distance between ______.
Earth and the Sun
About when did the Big Bang happen?
About 14 billion years ago
Which description fits the gas and ice giants?
Large, far from from the Sun, made mostly of gas and ice
Which object has the strongest gravitational pull in our solar system?
The Sun
Venus takes about 243 Earth days to spin once on its axis. What is that measuring?
a Venus day
Why do astronomers use AU instead of kilometers or meters?
Distances in space are huge, so AU makes the numbers smaller
What happened at the very beginning of the Big Bang?
Everything began in a hot, dense state and began expanding
How does the star in the center organize the planets in a solar system?
Its gravity holds the planets in orbit around it
Two objects move farther away from each other. What happens to the gravitational pull between them?
It gets weaker
Mars takes about 687 Earth days to travel all the way around the Sun. What is that measuring?
a Mars year
A planet has an orbital radius of 5 AU. What does that tell you?
It orbits five times further from the Sun than Earth does
In a collapsing nebula, gravity pulls matter together. What happens next as denser material “sinks”?
It moves towards the center and forms a star
Most moons around a planet orbit in a similar pattern (direction, tilt, shape). Why?
They are all formed from the same spinning disk of material
Which two things determine how strong the gravitational pull is between two objects?
Mass and Distance
Neptune is far from the Sun and has a much longer year than Earth. Which explains this?
It has a much bigger orbital radius than Earth
Planet X orbits at 0.4 AU, Planet Y at 1.0 AU, and Planet Z at 5.2 AU. Which statement is true?
Planet Y has the same orbital radius as Earth
What group of planets in our solar system formed first?
The Gas Giants
One moon’s orbit breaks the pattern of all the others. What is the best explanation?
It probably started on the same path, but something changed its course later