KEY CONCEPT

Space exploration
benefits society.
Sunshine State BEFORE, you learned NOW, you will learn
STANDARDS • Light and other radiation carry • How space exploration has
SC.H.1.3.3: The student information about space helped us to learn more
knows that science dis- about Earth
• Astronauts explore space
ciplines differ from one
near Earth • How space technology is used
another in topic, tech-
on Earth
niques, and outcomes
but that they share a
common purpose, phi-
losophy, and enterprise.
SC.H.3.3.6: The student
knows that no matter THINK ABOUT
who does science and
mathematics or invents How does Earth look from space?
things, or when or
where they do it, the This photograph of Earth over
knowledge and tech-
nology that result can
the Moon was taken by the
eventually become crew of Apollo 8. The Apollo
available to everyone. missions provided the first
images of our planet as a
whole. What do you think we
can learn about Earth from
VOCABULARY
impact crater p. 696
photographs taken from space?

Space exploration has given us

new viewpoints.
Space exploration enriches us in many ways. Throughout history,
the study of stars and planets has inspired new ideas. As we meet the
challenges of space exploration, we gain valuable technology. Space
exploration is also an exciting adventure.
Space science has advanced knowledge in other scientific fields,
such as physics. For example, observations of the Moon and other
bodies in space helped scientists understand how gravity works.
Scientists figured out that the same force that causes an object to fall
MAIN IDEA WEB to the ground causes the Moon to orbit Earth.
Record in your notes
important information Finally, the study of other worlds can teach us about our own.
that space exploration
has provided about Earth.
Earth has changed considerably since its formation. By comparing
Earth with different worlds, scientists can learn more about the history
of Earth’s surface features and atmosphere.

check your reading Identify some benefits of space exploration.

Chapter 19: Exploring Space 695

 Formation of a Crater

A large object from space falls The object explodes as it strikes As the rock springs back from
toward the surface at a very the surface, compressing and the impact, material is thrown
high speed. fracturing the rock underneath. out of the crater.

Wolf Creek Crater

in Western Australia

Distance: 853 meters (2800 ft)

Surface Features
Exploration of other worlds has helped us learn about the impacts of
space objects. When an object strikes the surface of a larger object in
space, it explodes and leaves behind a round pit called an impact crater.
The illustration above shows how an impact crater forms.
Earth has little evidence of impacts because its surface is constantly
being worn down by wind and water and altered by forces beneath the
surface. However, impact craters remain on the Moon, Mercury, and
many other bodies that have no wind or liquid water.

Atmosphere
We are also learning about Earth’s atmosphere from space exploration.
Earth’s temperature allows liquid water to remain on the surface.
Mars and Venus, the planets closest to Earth, have no liquid water on
their surfaces. By comparing Earth with those planets, we can see how
liquid water has affected the development of Earth’s atmosphere.
Another area of study involves the energy Earth receives from the
Sun. Many scientists think that small changes visible on the Sun’s
surface can affect weather on Earth. These changes may have caused
periods of cooling in Earth’s atmosphere.
check your reading What have scientists learned about Earth’s past from studying
bodies in space?

696 Unit 6: Space Science

 Weathering
SKILL FOCUS
How does weather affect evidence of Predicting
impacts on Earth?
PROCEDURE
1 Fill a shoebox lid halfway with sand, and smooth the surface with
a ruler. MATERIALS
• 2 shoebox lids
2 Create three craters by dropping a golf ball into the sand from a height • sand
of 70 cm. Remove the ball carefully. Leave the lid inside the classroom. • ruler
• golf ball
3 Repeat steps 1 and 2 outdoors, leaving the lid in an area where it will be
exposed to the weather. TIME
30 minutes
4 Check both lids after 24 hours. Observe changes in each one.

WHAT DO YOU THINK?

• How did the craters in the sand that you left outdoors differ in appearance
from the craters in the sand that remained inside?
• What aspect of weather caused any differences you observed?

CHALLENGE What natural processes besides weather can affect

evidence of impacts from space objects on Earth?

Space technology has practical uses.

Space exploration has done more than increase our knowledge. It has
also provided us with technology that makes life on Earth easier. Each
day you probably benefit from some material or product that was
developed for the space program.

Satellite Views of Earth

One of the most important benefits of space exploration has been the
development of satellite technology. Satellites collect data from every
region of our planet. The data are sent to receivers on Earth and con-
verted into images. Scientists have learned from the space program
how to enhance such images to gain more information.
Weather satellites show conditions throughout Earth’s atmosphere.
Images and data from weather satellites have greatly improved weather
forecasting. Scientists can now provide warnings of dangerous storms
long before they strike populated areas.
Other satellites collect images of Earth’s surface to show how it is
being changed by natural events and human activity. Satellite data are
also used for wildlife preservation, conservation of natural resources,
and mapping.

Chapter 19: Exploring Space 697

 Technology Spinoffs
Have you ever come up with a new way to use something that was
designed for a different purpose? NASA often creates advanced tech-
nology to meet the special demands of space travel. Many spinoffs of
technology from the space program
can be found in homes, offices,
schools, and hospitals.
Everything on a spacecraft must
be as small and lightweight as possi-
ble because the heavier a spacecraft
is, the more difficult it is to launch.
Design techniques developed to
meet this need have improved
devices used on Earth, such as
tools for diagnosing diseases and
devices that help people overcome
disabilities.
Materials and parts on a space-
craft have to endure harsh conditions,
such as extreme heat and cold. Many
NASA designers helped new homes and buildings contain fire-resistant materials developed
develop a system that
allows this boy to
for the space program. Firefighters wear protective suits made from
communicate by using fabric originally used in space suits. NASA has also helped design
eye movements. devices that allow firefighters to avoid injury from inhaling smoke.
Humans need a safe environment in spacecraft and space stations.
NASA has developed systems for purifying air, water, and food. These
systems now help protect people on Earth as well as in space.

KEY CONCEPTS CRITICAL THINKING CHALLENGE

1. How has space exploration 4. Infer Hurricanes form in the 6. Predict It takes over a year for
helped us learn about impacts middle of the ocean. Why a spacecraft to reach Mars and
of space objects on Earth? would satellites be useful in return to Earth. If astronauts
2. How do satellites provide tracking hurricanes? ever travel to Mars, they will
images of Earth’s surface and 5. Apply What space-technol- need a spacecraft that can
atmosphere? ogy spinoffs might be used in recycle air and water. How
a school? might such technology be
3. Give two examples of technol-
adapted for use on Earth?
ogy we use on Earth that is a
result of space exploration.

698 Unit 6: Space Science