Transcript Slide 1

Astronomy
Unit 1
Earths Place in the Universe
What do you think?
1. What is a light year?
2. Why is the light year important in
astronomy?
Note: What do you think? questions are to be answered in your notebook
in complete sentences.
Our Place in Space
• Earth is average – we don’t occupy any
special place in the universe
• Universe: all space, time, matter, and
energy
Our Place in Space
• Astronomy is the study
of the universe
• Distance scales are
very large, measured in
light-years (the distance
light travels in a year –
about 10 trillion miles)
• Light-Year is a unit of
distance, not time
• Powers of Ten
Our Place in Space
This galaxy is about 100,000 light-years across:
What do you think?
1. What is a constellation?
2. Why do we have constellations?
Note: What do you think? questions are to be answered in your notebook
in complete sentences.
A View to Observe
Simplest way to
observe the universe
is to look at the night
sky
About 3000 stars are
visible at any one
time
Stars are distributed
randomly but the
human brain tends to
find patterns
A View to Observe
Stars can be grouped into
constellations: figures
having meaning to those
doing the grouping
A useful star is Polaris,
which is almost due north
of Earth
Astrology, predictions
based on the star patterns
at their birth, zodiacs, is not
a science.
Video Link
Constellations
In 1996,
astronomers
spotted 47 Ursae
Majoris b, an
exoplanet orbiting
the star 47 Ursae
Majoris. Then in
2001, another exo
is found circling 47
Ursae Majoris. This
drawing shows the
star around which
two Jupiter-size
exoplanets orbit.
Ursa Major
Legends/Myths associated with this grouping
of stars from these civilizations:
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Greek
Iroquois
Zuni
Housatonic
Basque
Chinese
Arabian
German
English
Assignment 1:
• Use the stars in Ursa Major to
design your own constellation.
• Write a story to go with your new
constellation.
• Share your constellation picture
and story with the class.
Assignment 2:
• Choose one of the 88 official IAU
constellations to research and
present to the class.
• Specific requirements on Google
Classroom
Wrap-up:
• Consider all the presentations
together. What do you note? What
are you taking away with you?
• Choose the 1 constellation that
stands out to you? Why does it?
• Does this project raise any
questions in your mind?
Earth’s Orbital Motion
Stars do not appear in quite the same place
day to day due to Earth’s rotation around Sun;
Earth’s Orbital Motion
12 constellations that Earth moves through
during the year are called the zodiac
Earth’s Orbital Motion
Seasonal changes to night sky are
due to Earth’s motion around Sun
Animation Link
The Ecliptic
The ecliptic marks the path of the sun. It’s
the projection of Earth’s orbit onto the sky.
Earth’s Seasons
Video Link - Seasons
Motion of the Moon
The Moon takes about
29.5 days to go
through one whole
cycle of phases.
Phases are due to
reflection of varying
sunlight visible from
Earth.
Time to make full
360° around Earth is
about 2 days shorter.
Motion of the Moon
Eclipses occur when Earth, Moon, and Sun
form a straight line
Video Link
Motion of the Moon
Lunar eclipse:
• Earth is located between the Moon and Sun
• partial when only part of the Moon is in shadow
• total when entire Moon is in shadow
Motion of the Moon
Solar eclipse:
Moon is between
Earth and Sun
• partial when only
part of Sun is
blocked
• total when it all is
• annular when Moon is too far from Earth for total
Motion of the Moon
Eclipses don’t occur every month because
Earth’s and Moon’s orbits are not in the same
plane.
Summary of Unit 1
Astronomy is the study of the universe.
Seasons on Earth are caused by the tilt of
Earth’s axis as it orbits the Sun. The more
direct the rays of light hit, the warmer it is.
Phases of the Moon are caused by how we see
the reflected light from the Sun off the surface
of the moon as it orbits the Earth.
Solar and Lunar Eclipses occur due to the
alignment in orbit; they only occur
occasionally when orbits are in the same
plane.
Review Assignment:
- Astronomy Today (textbook)
Page 30: Questions 2, 3, 5, 8,
9,
10, 13, and 14.
Page 31: Problem 1
- Study Guide Worksheet
- Vocabulary