8.11: Satellites
page 346
Key Concepts:
1. Careful observation of the night sky can offer clues about the motion
of celestial objects.
2. Celestial objects in the Solar System have unique properties.
3. Some celestial objects can be seen with the unaided eye and can be
identified by their motion.
4. The Sun emits light and other forms of radiant energy that are
necessary for life to exist on Earth.
5. Satellites have useful applications for technologies on Earth.
6. The study of the night sky has influenced the culture and lifestyles of
many civilizations.
- Earth’s natural satellite is the Moon, it orbits around Earth.
- Man made satellites also orbit Earth at various altitudes.
- These satellites are used for many purposes, such as; weather detection,
communication, navigation, and explore the universe.
- The International space Station is another man made satellite
.
- The Space shuttle is another satellite but this one can return to Earth to be
reused.
- 1957 Russia sent the first satellite into space, it is known as Sputnick 1.
- Canada sent their first satellite into space in 19672, called Allouette 1.
Staying in Orbit
- Gravity should pull these satellites down to Earth, but it does not.
- The forward motion is equal to the gravitational pull of Earth therefore the
satellites stay in their orbits.
- If the forward motion is greater then the gravitational pull, the satellite will
continue out into space.
Types of Orbits
Low Earth Orbit Satellites
Medium Earth Orbit Satellites
Geostationary Orbit Satellites
Check Your Learning
Questions 1 – 9, page 351
In Summary:
- Many countries, including Canada, have launched artificial satellites into
Earth orbit to study Earth and objects beyond Earth.
- Objects need to be sent into orbit with enough velocity to avoid being
pulled back to Earth’s surface by gravity.
- Different types of orbit (low, medium, and geostationary), are categorized
based on the satellite’s altitude.
- Satellites have many different applications for technologies on Earth, such
as; satellite television, and global positioning systems.