Universe and Big Bang
What is the universe?
All of space and everything within it, including matter and energy.
What galaxy contains our Solar System?
The Milky Way Galaxy.
How many planets are in our Solar System?
Eight
What force pulls planets toward the Sun?
Gravity
What number planet is Earth from the Sun?
Third.
Approximately how long ago did the Big Bang occur?
About 13.8 billion years ago.
Is our Solar System located at the center of the Milky Way?
No.
Name the four inner planets
Mercury, Venus, Earth, and Mars
Is inertia a force?
No. It is the tendency of an object to resist a change in its motion.
Name one characteristic that makes Earth suitable for life
Examples: liquid water, atmosphere, appropriate distance from the Sun, or magnetic field.
What does the Big Bang Theory explain?
How the universe began in a hot, dense state and rapidly expanded
What part of the Milky Way contains our Solar System?
The Orion Arm
Name the four outer planets
Jupiter, Saturn, Uranus, and Neptune
In an orbit, which direction does gravity pull a planet?
Inward toward the Sun
Why can scientific models change?
New evidence, observations, or technology can lead scientists to revise them.
What began forming as the universe expanded and cooled?
Stars and galaxies.
Put these in order from largest to smallest: Earth, Universe, Milky Way, Solar System.
Universe → Milky Way → Solar System → Earth
Which planet is the largest, and which feature is associated with it?
Jupiter; the Great Red Spot.
What would happen if the Sun's gravity disappeared but Earth kept its current motion?
Earth would continue moving forward instead of following its curved orbit
Scientists once used a model that placed Earth at the center. What evidence helped change that model?
Telescope observations and other evidence showed that Earth orbits the Sun.
Put these events in the correct order: stars and galaxies form, universe begins expanding, Solar System forms, Earth forms
Universe begins expanding → stars and galaxies form → Solar System forms → Earth forms
A student says, “The Milky Way is located inside our Solar System.” Explain the mistake
The Solar System is inside the Milky Way, not the other way around.
Compare the inner and outer planets
Inner planets are smaller and rocky; outer planets are much larger gas or ice giants.
Explain how gravity and inertia work together to create an orbit
Inertia means the moving planet tends to continue forward, while gravity continually pulls it toward the Sun. The planet's path curves into an orbit.
A newly discovered planet has liquid water, an atmosphere, and an appropriate distance from its star. Why would scientists be interested in studying it?
Those conditions are similar to characteristics that make Earth suitable for life.