1. Life in our solar system
Unit 5
Life in our solar system

2. 7.9A Characteristics of the Solar System
Student Expectation
The student is expected to analyze the characteristics of objects in our solar system that allow life to exist such as the proximity of the Sun, presence of water, and composition of the atmosphere.

3. Proximity to the Sun
Proximity to the Sun contributes to temperature ranges experienced by a celestial body.
Distances that are too close or too far from the Sun create extreme temperature conditions
that are considered inhospitable to life.

4. Habitable Zone Earth is around 93,000,000 Miles from the Sun, which is
a distance favorable to
supporting life.
Venus is too hot (464° C),
and Mars is too cold (-65° C).
Earth’s average surface
temperature
Is 15° C, or 60° F.

5. Partner Discussion How does the distance from
the Sun affect the conditions necessary for life?’
Distances that are too close or too far from that Sun create
extreme temperature conditions that are considered
inhospitable to life.

6. Composition of the Atmosphere
The presence and composition of an atmosphere contributes to the ability of life to exist.
Atmospheric gases help regulate extreme temperature variations and ozone in the atmosphere
shields living things from harmful ultraviolet radiation. The magnetosphere, formed by Earth’s
magnetic field, protects life from the charged particles of the solar wind.

7. Earth’s Atmospheric composition by the Numbers
Without greenhouse gases, such as
carbon dioxide and water vapor
keeping the Earth warm, Earth’s
Temperature would be -33° C.

8. Presence of Water
Earth is known as the water planet with about 70% of its surface covered by water.
All life on Earth depends upon the presence of water. There is geological evidence that
liquid water was once present on the surface of Mars. Scientists speculate that water
exists, in various states of matter, on other celestial bodies in our solar system.

9. Discuss with a shoulder partner ‘Earth supports life while
the nearby Moon does not. Describe three reasons why
The Moon cannot support life compared to the Earth.’
The three characteristics (atmosphere, gravity, and water
are all possible answers).

10. 7.9B Accommodations for Space exploration
Student Expectation
The student is expected to identify the accommodations, considering the characteristics of our solar system, that enabled manned space exploration.

11. Microgravity Astronauts must exercise regularly
while in space because a
microgravity environment can
cause muscles and bones to 
become weak and less dense.
Handles, tethers and Velcro® straps
are accommodations
that help astronauts to move around,
sleep safely and
complete other tasks that normally
utilize the force of gravity.
Microgravity video clip

12. Partner Discussion
An astronaut is trying to move from one area of the space shuttle to another. What accommodations does this astronaut need?
The astronaut needs hand grips or grab bars to grab and pull or push their way to the other area.

13. Ultraviolet Radiation
The visor is coated with a thin
layer of gold  that filters
out the sun's harmful rays.
Most of the spacecraft windows
are coated with
ultraviolet blockers.
The EVA (extra vehicular activity),
or spacewalk suit has a layer of
material to block ultraviolet radiation.

14. Micrometeoroids Micrometeoroids are tiny Meteoroids traveling fast
enough to damage a
spacecraft, or spacesuit.

15. Partner Discussion
Explain why astronauts need special accommodations to live in space.
Space is a harsh and dangerous environment for humans. Humans need air to breathe, a way to communicate, protection from extreme heat and cold, protection from micrometeoroids, a way to perform daily routines, and a way to exercise to maintain muscle and bone strength.

16. Gravity assist maneuver (Gravitational Slingshot)
Gravitational assist is a way of using
the motion of a planet to accelerate
a space probe on its journey towards
the outer planets.
gravitational slingshot video

17. Partner Discussion Why do you think gravitational slingshots are used?
A spacecraft traveling from Earth to an inner planet will increase speed because it is falling toward the Sun, and a spacecraft traveling from Earth to an outer planet will decrease speed because it is leaving the vicinity of the Sun.