Space

What is space?
• When you look at the night sky you can see many beautiful stars. If you are out in the country or camping in the mountains or the desert away from the city lights, you may see thousands of them. You may even be able to see part of the Milky Way.
In a town or city, you can't see nearly as many stars because the city lights create a glow in the sky masking many of them.

Stars
• There are several different kinds of stars in the sky.
Some are very big. A couple of stars have been found that are 100 to 200 times larger than the sun. Some very old stars are smaller than the
Earth. Scientists study stars and place them in groups based on how they are alike and how they are different.

Our Solar System
• Our solar neighborhood is an exciting place. The Solar
System is full of planets, moons, asteroids, comets, minor planets, and many other exciting objects.

The Planets of our
Solar System

The Inner Planets plus Pluto

Our Solar System

Our Star: the Sun and its planets

Our Sun with some other stars

Some other stars

Mercury
• Smallest terrestrial planet
• Closest to the sun
• Virtually no atmosphere

Venus
• Similar to Earth in size and mass
• 7.5 months in its year
• 8 months for one day
• Rotates from east to west (most go from west to east)

Earth
• Only planet in our solar system with oxygen and liquid water.
• Home to millions of species.
• It is the largest of the four rocky planets.
• It has an atmosphere that is
78% nitrogen and 21% oxygen, with trace amounts of water vapor, carbon dioxide and other gaseous molecules .

Mars
• The Red Planet
• Its atmosphere is
95% carbon dioxide
• Possibly had water at one time
• Mars is titled on its axis and has seasons

Jupiter
• Largest and most massive planet in our solar system
• Thick atmosphere made up of hydrogen and helium
• Dozens of moons

Saturn
• Second largest planet
• Rings made of chunks of ice and rock
• Titan, a moon of
Saturn, was discovered in 1665

Uranus
• Has rings similar to
Saturn’s
• It rotates from top to bottom instead of sideways like Earth does
• 25 or more moons

Neptune
• A cold blue planet
• Visible clouds
• Believed to be slowly shrinking because of internal heating
• At least 13 moons

Pluto
• Dwarf planet
• Pluto is usually farther from the
Sun than any of the eight planets; however, due to the eccentricity of its orbit, it is closer than Neptune for 20 years out of its 249 year orbit.
Pluto crossed Neptune's orbit
January 21, 1979, made its closest approach September 5,
1989, and remained within the orbit of Neptune until February
11, 1999. This will not occur again until September 2226