Vocab
The force that pulls objects toward one another.
Gravity
Gravity is stronger when objects have more of this.
Mass
All galaxies formed because of this force.
Gravity
The force that keeps planets moving around the Sun.
Gravity
In galaxy models, arrows pointing inward usually show this force.
Gravitational Force
The path an object follows as it moves around another object due to gravity.
Orbit
Gravity is stronger when objects are closer together or farther apart?
Closer together
The galaxy that contains Earth and our solar system.
The Milky Way
The solar system formed about how many billion years ago?
4.6 billion years ago
Curved arrows in a galaxy model usually show this motion.
Rotation
A huge system of stars, gas, dust, and other objects held together by gravity.
Galaxy
True or False: Objects in orbit are not affected by gravity.
False
The Milky Way is one of how many galaxies in the universe?
Hundreds of billions
What was pulled together to form the solar system?
A disk of gas and dust
Why does the moon orbit Earth instead of the Sun?
Because it is closer to Earth, so Earth’s gravity pulls it more strongly
The process in which gravity pulls gas and dust together to form a star.
Star Formation
Which object pulls with more gravitational force: one with a large mass or a small mass?
The object with Large Mass
True or False: The Milky Way is so large that it is not affected by gravity.
False
Why do planets stay in their orbits?
Because of the pull of gravity
What force pulls gas and dust together during star formation?
Gravity
The collection of the Sun and all objects that orbit it.
The Solar System
Two factors that affect gravitational pull.
Mass and Distance
The three main types of galaxies.
Spiral, elliptical, and irregular
Which planet feels the strongest gravitational pull from the Sun because it is closest?
Mercury
When modeling gravitational pull between planets and the Sun, what two factors must be considered?
Distance and Mass