Download Unit 5 – Space Exploration - St. John Paul II Collegiate

Unit 5 – Space Exploration
Read page 352

The celestial bodies and events,
such as eclipses, comets, meteors,
aurora borealis, stars, solstice, and
equinox, have fuelled the human
imagination, marked the passage of
time and foretold changes in seasons.
The information was passed from
generation to generation and from
culture to culture as legends and
folklore.

Inuit, in the high Arctic, used the
width of a mitt held at arm’s length to
gauge the height of the sun above the
horizon. When the sun rose the
height of one mitt width, it meant the
seal pups would be born in two lunar
cycles.

The First Nations people of the
Pacific Northwest thought the night
sky was a pattern on a great blanket
overhead. This blanket was held by a
spinning world pole, the bottom of
which rested on the chest of a woman
underground named Stone Ribs.

The Ancients used rock structures
and buildings to align with stars (ex.
2700 BC pyramids built in Ancient
Egypt).

The Celts created Stonehenge to
mark winter and summer solstices.

The Mayan built a cylindrical-
shaped tower to celebrate the
equinox.

2000 years ago Aristotle
developed the Earth centred model.

1530, Copernicus developed the
Sun-centred model.
Topic 1: For Our Eyes Only
Read page 356.
A frame of reference is a set of axes of
any kind that is used to describe the
position or motion of things.
For example:
 Fixed Earth – when we look up at the
sky, our sense tells us that Earth doesn’t
move, but rather the sky and stars move
around the Earth.
 Fixed Stars – if we measure positions
and motions of celestial objects relative
to the stars, it is as if the stars are not
moving. Rather it is the Earth moving
around the stars!
BLM 5-1
What Our Ancestors Saw
Read page 357.
Celestial Body – sun, moon, stars, planet.
Constellation – stars that make
unchanging patterns in the sky (little
dipper).
Read “Did you Know” on page 357.
Read Ancient Legends on page 358.
Through observation our ancestors
discovered that:
- stars make unchanging patterns in the
sky which looked like objects that
they named.
- They could use the movement of stars
to mark months and seasons which led
to the development of the calendar.
A given star rises and sets 4 minutes
earlier than the day before – so each
month has its own set of stars.
- The Sun, Moon and Planets rise and
set at different rates from the stars.
Sky Co-ordinates
Read page 359.
To measure a celestial body’s location in
the sky, you need 2 coordinates (both
measured in degrees):
1)The azimuth – the angle in degrees,
clockwise from the north. Measured
with a compass.
2)
The altitude – the angle in
degrees, above the horizon.
Measured with an astrolabe.
Altitude-azimuth coordinates locate a
celestial body relative to a fixed Earth.
Work on practice problems on page 359,
#1-3.
BLM 5-3.
Page 360 – an example of how to
construct an astrolabe.
The Stars as a Frame of
Reference
Read page 363.
- since stars don’t change their
positions relative to each other to any
observable degree, ancient
astronomers concluded that the stars
were fixed in the sky. However the
planets, Moon, and Sun, do change
their position relative to the stars. By
tracking the motion of the Sun, Moon,
and planets, relative to the stars,
people were able to create models of
the solar system.
- Track the position of Mars relative to
a clump of stars in the sky.
Earth-centred model (geocentric
model) of the universe.
-everything orbits the Earth.
Read page 363.
-this is a model that organizes data. It
does not represent a wrong idea. This
model explains observations; that is you
could use it to predict seasons, eclipses,
the position of the sun in the sky, etc.
Note: mercury is closer to the sun than
Venus.
Sun-Centred Model of the Solar System
(Heliocentric)
-This model was developed by Copernicus.
In this model, the Earth revolves around
the Sun.
-Note: this model is ecliptic – the moon,
sun, and planets never move above or
below a plane as they travel around the
sun.
Ring of Students demonstration
- even if the entire room had been
revolving with the ring of students,
the student in the centre would have
observed the same thing.
Page 365 #1-5.