Solar System Unit Test Flashcards
Revolve
Go once around the sun
Rotation
Spin once on its axis
What two factors keep planets in their orbits and how?
Inertia and gravity. With inertia, the planet moves forward. With gravity, the planet is pulled sideways. The forward- sideways combo creates an ellipse orbit.
Why do we see one side of the moon only?
The moon rotates at the same speed it revolves.
What are two major differences with Earth’s orbit and the moon’s orbit? (A couple answers)
Moon- tilted orbit, revolves around Earth
Earth- not tilted orbit, revolves around sun
When it is one season in the Northern Hemisphere, it is the……..In the Southern Hemisphere.
Opposite
Why does the Earth have seasons?
It’s axis is tilted so while going around the sun, different hemispheres are hit more directly by the sun’s light.
When are the solstices for winter and summer for each hemisphere?
June 21: winter in SH, summer in NH
December 21: winter in NH, summer in SH
What is weight?
A measure of the force of gravity put on an object. That’s why you weigh different amounts on different planets- because they have different amounts of gravity pulling you down.
What is mass?
The amount of matter in an object
What is gravity?
A force that attracts all objects towards each other
How is gravity affected by mass?
An object with a greater mass has more gravity. It can pull more things to one object. For example, Mercury has a small mass and therefore cannot hold enough gases to have an atmosphere. Jupiter has a large mass and can hold many gases, moons, rings, and more.
How does distance effect gravity?
The farther two objects are from each other, the less gravity one object has on another. When two or more objects are very close to each other, their pulls on each other will be more effective. When they are farther away, the gravity isn’t as strong and may not pull the object very much.
How can the sun can have more mass than other stars yet not have as much volume?
Volume is basically the size of an object and mass is the amount of matter inside. Some other suns are bigger, but may not have as much matter inside of them.
Why do solar and lunar eclipses not happen each month?
The moon’s orbit around Earth is tilted. Therefore, the sun, moon, and Earth rarely line up perfectly to have either a solar or lunar eclipse.
What are the rules to be a planet?
- Orbits the sun
- Must be round
- Must clear the path of its orbit so there is no junk anywhere in it.
Why is Pluto not a planet?
Pluto doesn’t clear the path of its orbit, objects from the kuiper belt are in there.
What is an astronomical unit?
It is 150,000,000 km, the distance from the sun to the Earth. It is used for measuring the distance of things in and not too far away from our Solar System.
Order of planets’ distance from the sun
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
Inner planets shared characteristics:
Small, rocky, not very large atmosphere compared to the outer planets, some have plains, some have mts and volcanoes.
Why is Venus so hot?
Venus is hot because it’s atmosphere traps heat from the sun. When the sun’s rays hit the planet, they go through the atmosphere, and when reflecting back out to outer space they bounce back off the atmosphere. This is because the carbon dioxide in the atmosphere traps the heat waves from escaping, and the planet stays hot.
Why are the atmospheres of gas giants so thick?
The atmospheres of the gas giants are so thick because the planets has more mass, and therefore have more gravity. The gravity can hold many gases and give the planet an extremely thick atmosphere.
Outer planets shared characteristics:
Thick atmosphere, liquid surface, small and rocky core, rings, moons, very big planets!
What is the difference between weight and mass?
Weight can change, depending on how strong the gravity is pushing against it. However, the amount of matter in the object still would be the same.
