Ch 22
Exploring
Space
Radiation from Space
Photons of light travel in waves just
380 to 750 nanometers (millionths
of a millimeter) long.
Electromagnetic Radiation
• Stars give off different wavelengths of
light that make up the spectrum.
• Light travels as a transverse wave.
Light is the fastest thing in the Universe, traveling at 299,792,458 meters per second.
Light rays always travel in straight lines.
• Transverse waves have crests and
troughs.
• The distance from one crest to another
is called the wavelength.
• The frequency is the number of wave
crests that pass a certain point over
time.
crest
wavelength
trough
The
longest
light
waves
you can
see are
red, and
the
shortest
are violet
• Radio waves (longest)
•
•
•
•
•
•
Microwaves
Infrared
Visible (R.O.Y.G.B.I.V.)
Ultraviolet
X-Rays
Gamma Rays (shortest)
Light
rays
change
direction
as they
pass
from one
material
to
another.
This is
called
refraction
• Speed of light ≈ 300,000 km/s
• All forms of light travel at the same
speed.
• A Light Year (ly) is the distance it
takes light to travel in one year.
• About 9.46 trillion km/year
According to Einstein's theory of special
relativity objects gain mass as they speed up,
and that speeding up requires energy. The
more mass, the more energy is required. By the
time an object reached the speed of light,
Einstein calculated, its mass would be infinite,
and so would the amount of energy required to
increase its speed. To go beyond the infinite is
impossible.
Optical Telescopes
• Telescopes that use light to produce
magnified images of objects.
Galileo had to leave the university because he ran out of money but
his brilliant treatises on physical laws earned him a series of teaching
posts at Italian universities
Refracting Telescopes
 Refraction is the bending of light as
it passes through different
materials.
 A convex lens is used to bend the
light and is magnified.
 Galileo built the 1st refractor.
One day in 1608 a Dutch spectacle maker named Lippershey held a lens in each hand and peered
through both at once, accidentally discovering that 2 lenses placed in line would magnify an image.
He mounted a lens at each end of a tube and invented the telescope.
Refraction & Refracting Telescopes
Reflecting Telescopes
 Telescopes that use concave
mirrors to reflect the light from an
object to a focal point.
All things being equal, the
telescope that is easiest to
set up is the one that'll get
used by amateur
astronomers.
Forget about
magnification when
buying a telescope.
The size of the lens
or mirror is
WAYYYYY more
important!
Hubble Space Telescope
 Launched in 1990
 Placed in high Earth orbit, free of
atmospheric distortion.
You are not going to see anything remotely
like what you see on the NASA websites or
on calendars and posters through a
telescope at home. Those images were taken
by multi-million dollar spacecraft that were
processed by a team of scientists whose job is
to make pretty pictures. With the exception of
the planets and the Orion Nebula, you're going
to see a smudge of light through even the
largest amateur telescopes.
Radio Telescopes
 Used to map the Universe
 Detects objects
 Search for signs of intelligent life
on other planets
Early Space Missions
To leave orbit, spacecraft must move faster than 11 km/s
Newton’s Laws of Motion
Law of Inertia
 An object in motion will stay in
motion, an object at rest will stay at
rest.
 An outside force will change the
inertia.
Inertia
Law of Acceleration (Force)
 An accelerated mass creates
force.

F = ma

Newton (N) = kg • m/s2
a
Law of Action/Reaction
 For every action (force), there is an
equal action in the opposite
direction.
Reaction
Action
Rocketry
Solid Fueled Rockets
 Solid fueled rockets were invented
by the Chinese.

Difficult to control
Liquid Fueled Rockets
 Dr. Robert Goddard successfully
launched the first liquid fueled
rocket in 1926.
Rocketry is based on Newton’s 3rd
Law of Motion

Action
Reaction
• Notable Rockets:
German V-2 Rocket of WWII
 USA Saturn V Rocket for the
Moon missions.

Only one Gemini capsule was given a name , the first capsule was
called Molly Brown by Astronaut Gus Grissom.
Apollo
Artificial Satellites
• Satellites are objects that orbit around
another large object.
• Sputnik I was the 1st satellite to orbit
Earth (Russia, 1957)
• Hundreds of satellites orbit the Earth
today (weather, GPS, communications,
etc.)
• Satellites maintain their orbit as a result of
gravity & inertia counteracting each other.
• “Falling around Earth”
Inertia
Resulting Orbit
Gravity
Space Probes
• Satellites with instruments that travel
away from the Earth.
• Some orbit distant objects while
others land on surfaces.
Galileo studied Europa (one of
61 moons of Jupiter), Europa
may have an ocean and heat
under it’s ice. Maybe life!
• Notable Space Probes:

Mars:
• Vikings I & II (1974)
• Mariner Program
(Mercury, Venus also)
• Mars Pathfinder
w/ rover (1998)
• Spirit & Opportunity
(2004)

Venus:
• Venera program
(1960s-1970s)
• Magellan Program

Outer Planets & Objects
• Voyagers I & II
• Galileo (Jupiter)
• Cassini-Huygens
(Saturn & Titan)
• New Horizons (Pluto)
• Stardust probe (comet)
• NEAR-Shoemaker (asteroids)
Manned
Space
Missions
Yuri Gagarin was the first person in
space! Alan Shepard was the first
American in space. Neil Armstrong was
the first person on the moon. Who was
second?
Space Shuttle Program
• A set of reusable, Earth orbiting
spacecrafts by NASA.
• First launch in 1981 (Columbia)
• Other space shuttles include:




Challenger
Discovery
Atlantis
Endeavour
Challenger Disaster

Shuttle blew apart 73 seconds into its
mission. (January 1986)
Columbia Disaster

Shuttle broke apart during re-entry to the
Earth’s atmosphere 16 minutes before
landing (February 2003)
• The shuttles will be decommissioned in
2010 to prepare for missions to the moon.
• (Endeavour was originally scheduled to be decommissioned in
2010 after 18 years of service, but on July 1, 2010, NASA released
a statement saying the shuttle Endeavour mission was
rescheduled for February 27, 2011, instead of late November,
2010.)[
Space Stations
U.S. Skylab (1973-1979)
U.S. only solo attempt at building a
space station.
 Study the effects
of living
& working
in space.
 Crashed into the
Indian Ocean in
1979

Mir (1986-2001)



Russia’s 7th space station
Only supposed to last 5 years.
De-orbited in 2001 into the Pacific Ocean
International Space Station (ISS)
Construction began in space in 1998
 16 countries involved
 Support 7 crew members for 3-6 months
when finished.
