Gravity
What is gravity?
The force that pulls objects toward each other.
What is inertia?
The tendency of an object to resist a change in motion.
Name the four terrestrial planets.
Mercury, Venus, Earth, and Mars.
What are comets made of?
Ice, dust, and rock.
Where are most asteroids found?
In the Asteroid Belt between Mars and Jupiter.
What two things determine the strength of gravity?
Mass and distance.
How does inertia keep planets in orbit?
It keeps them moving forward while gravity pulls them toward the Sun.
Which terrestrial planet has evidence of water and life?
Earth
What is a meteor?
A space rock that enters Earth's atmosphere causing a streak of light to appear in the sky
What are asteroids made of?
Rock and metal.
Why do you weigh less on the Moon than on Earth?
The Moon has less mass, so its gravity is weaker
What would happen if gravity suddenly stopped?
Planets would fly off in a straight line due to inertia.
Name the four gas giants
Jupiter, Saturn, Uranus, and Neptune
Name a famous comet.
Halley’s Comet.
What is a meteoroid?
A small rock or dust particle in space.
What keeps planets orbiting the Sun?
The Sun’s gravitational pull.
What two factors keep Earth in orbit and around the Sun and the Moon in orbit around Earth?
gravity and inertia
What are gas giants mostly made of?
Hydrogen and helium
What direction does a comet’s tail always point?
Away from the Sun.
What happens when a meteoroid enters Earth’s atmosphere?
It becomes a meteor.
Who discovered the law of gravitational attraction
Sir Isaac Newton.
the distance between two objects increases, the force of gravity ____________.
decreases.
The giant or Jovian planets ___________________ than the inner planets.
are farther from the Sun
What is the difference between a meteor and a meteorite?
A meteor burns in the atmosphere; a meteorite lands on Earth.
What is a meteorite?
is a piece of rock or metal from space that survives its journey through Earth’s atmosphere and lands on the ground.