Two Types of Planets

Why do planets look bright?

Planets look bright to us because they are reflecting light from the sun. Planets, like satellites, do not produce light. They reflect it.

Sunlight hits the planet, bounces off the planet, travels into our eye.

What are the two regions of the solar

system? What is contained in each?

The inner solar system and the outer solar system are the two regions of the solar system.

The inner solar system contains the planets: Mercury, Venus, Earth, and Mars.

The outer solar system contains the planets: Jupiter, Saturn, Uranus, Neptune.

How did the planets form?

Planets formed during the beginning of the solar system. Bits of dust and gas began to clump together. These clumps eventually grew into our planets.

Could you model all the sizes of objects in the

solar system using sports balls?

Turn and talk to a partner. Discuss why you could. Or why you could not!

Inner Planets – Terrestrial Planets

These planets are often referred to as terrestrial planets. They are the four closest to the sun.

MercuryVenusEarthMars

The term “terrestrial planets” means Earthlike planets.

What they have in common:

All of the planets have a rocky crust.

The planets have layers from when they formed.

When the planets formed, the densest material sunk into the center of the planet, leaving the lighter rock around the crust of the planet.

Have atmospheres that were made from volcanic gasses.

Processes and Surface Features

Tectonics – Earth’s crust is split into tectonic plates, which are moved by a hot mantle.

These plates made our mountains, valleys, and other features.

Other planets do not have tectonic plates. However, forces from their mantle still twist, wrinkle, and stretch their crust.

Volcanism – occurs when molten rock moves from a planet’s hot interior onto its surface.

Volcanoes are fond on Earth, Venus, and Mars.

When a planet cools enough, volcanism will no longer occur.

Processes and Surface Features

Weathering and Erosion – the wearing down and transportation of material.

Heat can break down rocks and cause it to move around. Material can also be moved by gravity.

Processes and Surface Features

Impact craters – small objects that hit planet’s surfaces cause there to be holes, or craters on a planets surface.

Earth does not have many craters.

Earth is still “living.” Because of this, our craters are being erased.

Processes and Surface Features

Outer Planets – The Giant Gaseous PlanetsThese planets are the outer planets. Because of their composition, they are often called the giant gaseous planets.

Jupiter

Saturn

Uranus

Neptune

Made entirely of gas, such as hydrogen and helium.

What they have in common:

These planets have so much gas that they have a great amount of mass.

Much larger than the terrestrial planets.

Much colder outer layers than the terrestrial planets.

Inner part of the planet gets warmer.

Planets still have layers.

Why would the outer planets have cooler surface temperatures?

Turn and talk to your neighbor

What features do the outer planets have that the inner planets do not? What features do the inner planets have that the outer planets do not?

Turn and talk to your partner about this!

Based off of the readings that we have done in class and what you know, how do we gather information about the outer planets?

Turn and talk to your partner about this!

If we found a new planet in a distant galaxy, what is one way we would know if the planet was “living”?

Turn and talk to a partner about your answer!