Transcript Unit E: SPACE EXPLORATION

Science 9
Aim: Introduction to Space
Agenda
1. Unit Test
2. Lunch
3. Introduction to Space Notes
Unit E:
SPACE EXPLORATION
Human understanding of both Earth and space
has changed over time.
Technological developments are making space
exploration possible and offer benefits on Earth.
Nordic Optical
Telescope
in the Canary Islands
Optical telescopes, radio telescopes, and other
technologies advance our understanding of space.
Early Views of the Cosmos
The movements of celestial bodies have been
observed for thousands of years
Ancient cultures
explained their
observations of
bodies in space
with myths and
legends
Early Views of the Cosmos
The First Nations
peoples of the
Pacific Northwest
thought the night
sky was a pattern
on a great blanket
overhead
Early Views of the Cosmos
Many Ancient Civilizations Celebrated
Annual Cosmological Events…
 Winter and Summer Solstices
 Spring and Fall Equinoxes
Early Views of the Cosmos
Solstice
• Either of the two times in the
year when the Sun reaches its
highest or lowest point in the
sky at noon
• In the northern hemisphere,
the summer solstice occurs
near June 21 (longest day of
the year) and the winter
solstice occurs near December
21 (shortest day)
Early Views of the Cosmos
Solstice
These events were very important to early
cultures, as they indicated the coming
summer or winter
3500 years ago, ancient
people built Stonehenge
that help mark the
solstices
Early Views of the Cosmos
Equinox
• from the Latin for “equal night”
either of the two times a year
when the Sun crosses the
equator
• day and night are of equal
length
• usually on or around March
• 21 (“vernal equinox”) and
September 23 (“autumnal
equinox”)
Equator
MODELS OF PLANETARY MOTION
 Geocentric
 Heliocentric
Models of Planetary Motion
Geocentric (Earth-Centred)
• model of the universe that
places Earth at the centre
with the Sun, Moon, and
planets revolving around it
• proposed by the Greek
philosopher Aristotle about
2000 years ago
• could not explain the
retrograde (backward)
motionof Mars, Jupiter,
and Saturn
Models of Planetary Motion
Heliocentric (Sun-Centred)
• Model of the universe
that places the Sun at
the centre with the Earth
and planets revolving
around it
• Proposed by Polish
astronomer Nicholas
Copernicus in 1530
• Could not accurately
predict planetary motion
Models of Planetary Motion
Heliocentric (Sun-Centred)
About 100 years after
Copernicus, the scientists,
such as Galileo Galilei used
the new technology of the
telescope to provide solid
evidence for this theory
Models of Planetary Motion
Shape of Planets’ Orbit
In the early 1600’s Johannes Kepler, suggested that
planetary motion would be easier to predict if orbits
were elliptical rather than circular.
Kepler’s Model:
Discovery Through Technology
• Technology used to study space has evolved
throughout history. With each technological advance
came better explanations for what was observed.
Discovery Through Technology
Ancient Egyptians invented a device called a
“Merkhet” to chart astronomical positions and
predict star movement
Discovery Through Technology
Egyptians also invented
a device known as the
Quadrant around the
2nd century AD.
•
It was used to
measure a stars height
above the horizon.
Discovery Through Technology
Arabian astronomers
used the “Astrolabe”
to make accurate
charts of star
positions
Discovery Through Technology
In the 14th Century, astronomer Levi ben Gurson
invented the cross-staff.
• Used to measure the angle between the moon
and any given star.
Measurement in Space
The astronomical unit (AU) is a measure of distance
used to describe the position of planets relative to
the Sun. 1 AU is equal to the average distance from
the centre of the Earth to the centre of the Sun—
about 149, 599, 000 kilometres!
Why is this number an average number?
Measurement in Space
• Light travels at about 300,000 km/s
• A light-year is the distance that light travels in 1
year (about 9.5 trillion kilometres). It is used to
measure distances between stars and galaxies.
• The nearest star to Earth after the Sun, Proxima
Centauri, is around 4.3 light-years away
• How many kilometres is that?
Using Light Years Measure Distance...
and Time
Because some stars are so far away and we
know that their light takes time to get here.
Orion nebula – 1350 ly
Alpha Centauri – 4.37 ly
Time
• Because light years are measured in human
years they tell us how long the light took to
get to Earth.
• Depending on the objects distance, you are
seeing the light from the object as it was that
many years ago.
Orion nebula – 1350 ly = 1350 years ago
Alpha Centauri – 4.37 ly = 4 years 3 months ago
Homework for the weekend
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Read 371-405
P 376 # 1-7
P 383 # 1-7
P 391 # 1-4, 6-8
P 400 # 1-9
P 405 #1-7
Due Tuesday Dec 17. Email them to me if
you are not here next week.