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Chapter 1 Notes
Studying Space
Section 1 Astronomy: The Original Science
 The years, months, and days of our modern calendar are based on
observing our solar system.
o Year = earth’s orbit around the sun
o Month = moon’s orbit around the earth.
o Day = earth’s rotation on its axis
 Early astronomers helped people understand their place in the
universe.
o Ptolemy: The Ptolemaic Theory stated that Earth was the
center of the universe and everything revolved around it.
o Copernicus: Believed the sun was the center of the universe,
and all the planets orbited the sun.
o Brahe: recorded precise observations of the planets and
stars and believed the sun and moon revolved around the
Earth and the other planets revolved around the sun.
o Kepler: announced all planets revolved around the sun and
he also stated the 3 Laws of Planetary Motion.
o Galileo: used a telescope to discover craters and mountains
on our moon. Jupiter’s moons and sunspots.
o Newton: is responsible for the Law of Gravity and helped
explained why all the planets orbit the most massive object
in the solar system – the sun.
 Modern Astronomy
o Two developments were the invention of the telescope and
description of gravity.
o Edwin Hubble proved other galaxies existed beyond the
Milky Way.
Chapter 1, Section 2 Notes
I. Telescopes
A. What is a telescope?
1. Telescope use light to view objects in the distance.
2. Telescopes is an instrument that gathers electromagnetic
radiation from objects in space.
B. Optical Telescopes
1. Most common type of telescope
2. Studies visible light from objects in the universe
3. Has a focal point or the point where light goes through the
lens or reflects
4. Has two parts to the telescope
a. objective lens – collects light and forms image at back of
telescope
b. eyepiece – lens magnifies the image created by objective
lens
C. Other big telescope ideas
1. Astronomers use them to gather information about objects in
space. They use reflecting telescopes more.
D. Refracting versus reflecting telescopes
Definition
Parts
Advantages
Refracting Telescope Reflecting Telescope
Uses a set of lenses to Uses a curved mirror
gather and focus light to gather and focus
from distant objects. light from distant
objects.
Uses the focal point, Uses a focal point,
eyepiece, starlight,
eyepiece, starlight,
and lens.
and lens.
 Has larger
mirrors which
means there is
more light.
 Curved mirrors
are polished on
the side so it
prevents light
from entering.
 Colors of light
are seen in
focus.
 Preferred by
many
astronomers.
Disadvantages
 Images aren’t
perfectly
focused.
 Size of the
telescope limits
the lens size.
 Not preferred by
many
astronomers.
Chapter 1 Notes
Studying Space
Section 2: Telescopes
 Electromagnetic Spectrum
o All of the frequencies or wavelengths of electromagnetic
radiation
 Radio waves
 Microwaves
 Infrared
 Visible
 UV
 X-ray
 Gamma
o Earth’s atmosphere blocks out most invisible radiation.
o Astronomers use waves from the EM Spectrum in telescopes
to detect radiation that can’t be seen.
o Radio telescopes – detect radio waves.
o Astronomers can link radio telescopes together to work like
a giant telescope to get more detailed images of the
universe.
o Scientists use telescopes in space because of their ability to
detect other objects.