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SPACE SYSTEMS UNIT
Chapters 26 & 30
26.1 Viewing the Universe
The Value of Astronomy
– Astronomy: the scientific study of the universe
– By observing the universe astronomers have:
 Made exciting discoveries, such as new planets,
stars, black holes, and nebulas
 Been able to learn more about the origin of Earth
and the processes involved in the formation of our
solar system
– Funded by federal agencies (NSF & NASA) as
well as private foundations and industries
LT 1: I can describe characteristics of the universe in
terms of time, distance, and organization.

Cosmology: the study of the origin,
properties, processes, and evolution of the
universe.
 Universe began about 14 Billion years ago
in one giant explosion, The Big Bang
 Universe is expanding and is very large and
objects within it are very far apart.

Organization of the Universe
– Earth is in a solar system
– The Solar System is in a galaxy (Milky Way
Galaxy)

Galaxy: a collection of stars, dust, and gas bound
together by gravity
– Beyond The Milky Way are billions of other
galaxies
Measuring Distances in the Universe

Astronomical unit (AU): approximates the
average distance between Earth and the sun
– About 150 million km

Light-year: distance between Earth and the
sun that light travels in one year
– Speed of light = 300,000 km/s
– 9.46 x 1012 km
– Closest star to Earth (aside from the Sun) is
4.22 light-years away
LT 2: I can identify the visible and nonvisible
parts of the electromagnetic spectrum.

Observing Space
– Electromagnetic Spectrum: all of the frequencies or
wavelengths of electromagnetic radiation (EMR)
– Humans only see Visible EMR
– Light travels at the same speed, but have different
wavelengths which produces the different colors
– Invisible EMR have shorter wavelengths than Violet or
longer wavelengths than Red

Discovered by Sir Frederick William Herschel in 1800 with a
thermometer
LT 3: I can compare refracting and reflecting telescopes.
Telescope: an instrument that collects EMR from the sky and
concentrates it for better observation.

Refracting Telescopes
– Use lenses to bend light
(refraction)


Objective lens gathers
light
Eyepiece lens magnifies
the light

Reflecting Telescopes
– Uses mirrors to gather
and focus light

– Lens focuses different
wavelengths of light at
different distances
which limits the size of
the objective lens.

Light is reflected off of
one lens onto a 2nd
mirror which then
reflects the light to the
eyepiece
Mirrors can be very
large without affecting
the quality of the image
LT 4: I can explain how telescopes for nonvisible electromagnetic
radiation differ from light telescopes.

Nonvisible EMR
Telescopes
– Each type of EMR must
have its own telescope
– Affected by Earth’s
atmosphere
– Most of these telescopes are
in space



Hubble Space Telescope
Chandra X-ray
Observatory
Spitzer Space Telescope
(infrared telescope)

Light Telescopes
– Reflecting and
Refracting Telescopes
– Largest Reflecting
Telescopes are in HI
Other Spacecraft

Voyager 1 & 2
– Launched in 1977
– Investigated Jupiter, Saturn, Uranus, and Neptune

Galileo
– Orbited Jupiter and its moons from 1995 – 2003

Cassini-Huygens
– Launched in 1997 and began orbiting Saturn in 2004

Spirit & Opportunity
– Explore Mars beginning in 2004
– Confirmed water had once been on Mars

Curiosity
– Most recent rover sent to Mars
– Started exploring the surface in Summer 2012