Download Observing the Solar System

Observing the Solar System
Chapter 14.1 [p. 538]
Early Ideas of the Solar System
• The Greeks thought that
they were inside a rotating
dome they called the
celestial sphere.
• The Greeks also thought
that the universe was
perfect and unchangeable.
• Earth is stationary; the
Greeks thought we are in a
geocentric system:
– The Earth is at the center of
the revolving planets.
Early Ideas Cont.
• In 140 A.D. Ptolemy
– theorized that the planets
moved on little circles that
move on bigger circles, this
explained why the planets
moved at different speeds.
– Ptolemy’s geocentric
model of the planets was
widely held for nearly 1,500
years after his death
Early Ideas Cont.
1500’s: Nicolaus
Copernicus
– 1543, Copernicus came up
with a theory that would
revolutionize the science of
astronomy … “The
Copernican Revolution”
– In a heliocentric system the
sun is at the center and the
planets revolve around the
sun.
Early Ideas Cont.
• 1600s: Galileo
– Galileo was the1st scientist to
use a telescope to look at
objects in the sky.
– Galileo made 2 discoveries
that supported the
heliocentric theory:
• Venus goes through phases
similar to Earth’s moon. These
phases could not be explained
if Earth was the center of the
system.
• Jupiter’s moons revolved
around Jupiter. Therefore not
everything in the sky revolved
around Earth.
Early Ideas Cont.
• Late 1500s - 1600s
– Tycho Brahe
• Observed the positions of the
planets for 20 yrs.
– Johannes Kepler
• Kepler analyzed Brahe’s data
to determine the shape of the
orbits.
• He discovered the orbits are
elliptical in shape.
Kepler’s Three Laws
• First Law: Planets move in ellipses, not
circles
Kepler’s Three Laws
• Second Law: A planet moves faster when
closer to the sun, slower when away
Kepler’s Three Laws
• Third Law: Planets closer to the sun move
faster than planet’s farther from the sun
Early Ideas Cont.
• 1665:Newton:
– Newton stated that two factors keep
the planets in orbit:
• Inertia and gravity
– Gravity: attracts all objects toward
each other
• The strength of gravity depends on
the mass of the objects and the
distance between them.
– Inertia: The tendency of a moving
object to continue in a straight line or
a stationary object to remain in place
• The more mass and object has, the
more inertia it has.
Components of our Solar System
•
•
•
•
•
•
•
•
•
Planets
Stars
Comets
Asteroids
Satellites
Space Trash
Dark Matter
Particles (Dust)
Electromagnetic radiation
(Photons)
Planets
• There are 8 planets:
Gas Giants
–
–
–
–
–
–
–
–
–
Mercury
Venus
Terrestrial
Planets
Earth
Mars
Jupiter
Saturn
Uranus (YOOR uh nus)
Neptune
Pluto
Astronomical Unit
• 1 AU (astronomical
unit) = the Earth’s
average distance from
the sun (about 150
million kilometers or
about 93 million miles)
How We Look Into Space!
• We can see far into space with the help of
telescopes, satellites and spectroscopes.
• There are many types of telescopes, most
of which collect and focus electromagnetic
radiation, including visible light.
Telescopes
• Visible Light Telescopes:
– Reflecting Telescope:
• 1668 Isaac Newton built this
type of telescope.
• Used a mirror instead of an
objective lens.
• Focuses a large amount of
light onto a small area.
– Refracting Telescope:
• 1609 Galileo used this type
of telescope to look into
space.
• Uses a convex lens to
gather large amount of light
and focus in onto a small
area.
Telescopes Cont.
• Radio Telescopes:
– Used to detect radio waves from
objects in space.
– Have curved surfaces, up to
305m in diameter
– Surfaces concentrate faint radio
waves from space onto small
antennas like those on radios.
– The larger the telescope is, the
more radio waves it can collect.
Telescopes
• Infrared Telescopes:
– Detect longer
wavelengths than
visible light
• A building that
contains 1 or more
telescopes is called
an observatory.
Telescopes
• 1897: Yerkes Telescope
– 1m in diameter
– Largest refracting telescope ever
built
– The lens is so large, it can collect
more light than any other refracting
telescope
• 1931: Karl Jansky
– Accidentally discovered radio
astronomy
– Tried to figure out what static was
interfering with radio
communications. The static was
coming from objects in space!
Telescopes
• 1963: Arecibo radio telescope
– Built in a natural bowl in the
ground
– It is 305m in diameter
– Located in Puerto Rico
• 1980: The Very Large Array
– 27 radio telescopes in New
Mexico
– They can be moved close
together or far apart
– They are linked together, so
they can be used individually
or as one giant telescope
25km in diameter.
Telescopes
• 1996: Keck Telescopes
– 2 of the largest reflecting
telescopes
– Located in Hawaii
– Each telescope is made of
36 smaller mirrors joined
together to make one 10m
curved mirror.
Satellites
• Most UV radiation, X-rays, & gamma rays are
blocked by the Earth’s atmosphere.
• In order to detect these wavelengths, astronomers
have placed telescopes on satellites and
launched them into space.
Satellites
• 1990: Hubble Space
Telescope
– HAPPY BIRTHDAY
HUBBLE!!!!!!!
– Launched April 24, 1990
– Can see objects in space
more clearly than any other
telescope.
Large Ant Nebula
Homework
• Read Section One of Chapter 14
• Do the questions at the end of the section,
page 544 1a,b,c,d; 2a,b,c; 3a,b,c