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The Tools of Astronomers
Pgs. C6-C7
Astronomy
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The branch of science that deals with “what’s up there”.
The study of the universe.
o Universe
 Everything that exists.
 planets
 galaxies
 stars
Astronomer
o Someone who observes the universe and tries to explain what was observed.
o There are different astronomers that study different parts of the universe.
o Professional Astronomers
 People who have made astronomy their career.
o Amateur Astronomers
 Observe the stars and planets with telescopes for their own enjoyment.
Why we study astronomy
o Mostly because of curiosity.
 People want to know and learn more about the universe.
 Stars can be beautiful to look at.
o Benefits
 Navigators use their knowledge of a star’s position to tell direction.
Tools of Astronomy
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Eyes
o Can observe day and night.
o Can observe the position of some planets and stars
o Can observe the position of the sun and moon in the sky.
 Do not look directly at the sun, it can harm your eyes.
Telescopes
o A device that collects light.
o Makes distant objects appear closer and larger.
o Most of what we know about the stars and planets comes from telescopes.
Robots and humans in space.
o Both have been to the moon.
o Only robots have been sent to study other planets.
Models, Theories, Hypotheses
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Models
o Simplify the world so we can understand it better.
 Ex. The Earth is not exactly a sphere but we use a sphere as a model of
the Earth.
Theory
o A well-tested scientific explanation supported by evidence.
o Allows us to make a prediction about a scientific event or idea
 Ex. The theory of gravity explains the past motion of planets and allows
us to predict their future motion.
Hypothesis
o A scientific explanation that has not yet been fully tested.
As more evidence is found through observation a theory’s certainty increases.
A theory can never be proven with complete certainty.
Science can only tell what is likely, not what is certain.
If new evidence does not support a theory, the theory must be changed.