The three brighter objects are Venus (center), Mercury (below) and Saturn (left). What is the difference between stars and planets?

What is the solar system? The sun is at the center of the solar system. The word solar means “of the sun.” The solar system is the objects of, or around, the Sun.

Besides the sun, the objects in the solar system include 8 planets and their moons: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

The solar system also contains several dwarf planets. These include Pluto, Eris, and Ceres.

How do we know all of this information about our solar system? Scientists created the telescope, which uses lenses to see distant objects. This telescope is designed after Galileo Galilei’s—a 1610 astronomer who discovered moons revolving around Jupiter.

Today, we have more advanced telescopes. Telescopes take pictures of and collect data about objects in the solar system.

The Hubble space telescope is probably the most famous. The reason the Hubble gets such excellent pictures is because it is outside of the Earth’s atmosphere. It is the atmosphere that distorts the images made by ground telescopes.

This is a Hubble ultra deep field infrared view of countless “entire” galaxies billions of light- years away.

They zoomed in. This is a close up of one of the darkest regions of the first photo.

What is the solar system? How do scientists study the solar system? Solar system = the objects of or around the sun Scientists study the solar system using telescopes.

What is a moon? A moon is an object that circles around a planet. Different planets have different numbers and sizes of moons.

Mercury and Venus do not have moons. Earth has one moon.

Mars has two moons.

Jupiter has at least 63 moons. Saturn has 49 moons.

Astronomers have discovered at least 27 moons around Uranus and 13 moons orbiting Neptune.

The sizes of the moons vary. Some are very small, while 7 are actually bigger than Pluto (Jupiter’s Ganymede—the largest; and Earth’s)

Moon are also called satellites. A satellite is an object in space that circles another object. Moon are natural satellites.

Man has also created their own satellites and put them into space. These provide weather information, data about the solar system, and are part of communication systems.

Why doesn’t Earth look like the moon? We’ve already learned about Earth’s atmosphere. Well, the moon doesn’t have an atmosphere. So, when objects collide with it, they form a crater. Therefore, the moon has more craters than Earth.

What is a moon? What is a satellite? Moon = an object that circles around a planet Satellite = an object that circles another object *natural: moons *man-made: TV, weather

What are the smaller objects in the solar system? 1. asteroids 2. comets 3. meteors

An asteroid is a rock that revolves around the Sun.

Most asteroids are located between Mars and Jupiter in the asteroid belt.

A comet is a mixture of frozen gases, ice, dust, and rock that moves in an irregular circle around the sun.

Comets seem to have tails. As a comet gets closer to the sun, it warms up. It becomes a glowing ball of gas. The energy from the sun pushes the gas outward, causing the tails that we see.

There are sand to boulder-sized particles also floating around in the solar system. These are called meteoroids. As soon as the meteoroid enters the Earth’s atmosphere it is called a meteor. Once the meteor reaches the ground it is called a meteorite.

Lesson Review 1. How have telescopes improved our knowledge of the solar system? Telescopes let us see objects that are farther away. 2. Describe Earth’s moon. Earth’s moon is a natural satellite. There is no atmosphere so it is covered with craters.

3. What is the difference between a moon and a satellite? Moons are natural satellites. There are satellites that aren’t moons. Moons have to circle a planet. Satellites could circle anything. 4. What does the solar system include? It includes the Sun, the planets, their moons, and smaller objects such as asteroids, meteoroids, and comets.

5. Mars and Mercury are alike EXCEPT A.they both have rocky surfaces. B.they both are far from the Sun. C.they both have moons. D.they both have oxygen. C. They both have moons. Mars has 2 moons, but Mercury doesn’t have any.