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23-04-18 1
Unit E
Space Exploration
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Background
• YOU are RESPONSIBLE for the MATERIAL. • NOT ALL the material will be presented in class-
only some will be highlighted or overviewed, key concepts, and harder material
• Whatever is not completed in class for that day is left up to you to read!
• Homework is assumed to be done every night. • Study for your PAT exam’s NOW!!!!
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Here we go…
• Section 1.1– You are responsible to review early views
about cosmos
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• Celestial bodies for years have:– fueled human imagination– marked the passage of time– foretold the changes in seasons
• Passed through generations & cultures, often as legends– Ex. Iroquois noting
constellations Ursa Major• The ‘great bear’
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Tracking Cosmological Events
• Solstice– 2 times a year- June 21, December 21– Sun reaches highest and lowest points in
the sky– Has an affect on tides on Earth
• Equinox– 2 times a year- ~March 21, ~September
21– Day and night are of equal length
• Also when sun crosses the celestial equator
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Geocentric Model• Earth is at the centre of
the universe– The moon, the Sun, and
other objects go around it. (note the order)
• Belief in this system was common in ancient Greece (Aristotle)
• Objects were attached firmly to the outermost sphere- called the ‘celestial sphere’– Like an immovable ceiling
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Copernicus Heliocentric model
• Sun is at the center with planets & Earth orbiting around it.
• Hypothesized by Copernicus in 1500s, confirmed by Galileo in 1600s using teloscope– Galileo ridiculed for it– Kepler confirms this stating
orbits were ellipses, not circles
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Kepler’s discovery
• Ellipse – an oval formed around two foci (a circle is formed around one focus); the orbital paths of planets traveling around the sun are ellipses.
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Can also use p. 375 for procedure
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1.2 Discovery Through Technology
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The Astronomer’s Tools
• As technology has improved, our understanding of the skies has also improved.
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Examples of technology used through Earth history.
• Sundials – measure the passage of time
• Merkhet (Egyptian) –charts star movement at night which then could tell time
• A star clock
• Quadrant (Egytpian) – measure star’s height over the horizon.
• Astrolabe (Arab) – make accurate star charts by measuring altitude– Also for predicting celestial movement, surveying,
triangulation, and local time
• Cross-staff – measure the angle between the moon and any star.
• Telescope – create accurate maps of our solar system
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The Immensity of Distance and Time in Space
• Astronomical Unit (AU) – a measure of distance used to describe the position of planets relative to the Sun– P. 379 diagram– 1 AU is equal to the average distance from the centre
of Earth to the centre of the Sun (149 599 000 km).• The Earth is 1.00 AU from the Sun. • The Moon is 0.0026 AU from the Earth. • Mars is 1.52 AU from the Sun. • Jupiter is 5.20 AU from the Sun. • Pluto is 39.5 AU from the Sun.
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The Immensity of Distance and Time in Space
• Light Year – the distance that light travels in 1 year (approximately 9.5 trillion km)– used to measure distances
between stars and galaxies.• The vast distances between stars
and Earth even takes time for light to travel. So when light from a distant star reaches our eyes it could be thousands of years old. – 1 light year = 63, 241AU
This is 10000 light years away!
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• Amy was given a list of notes on early theories of celestial bodies (sun, moon, and planets)– A. Earth centered– B. Sun centered– C. proposed in the 1500s– D. proposed 2000 years ago– E. proposed by Aristotle– F. proposed by Copernicus
• The notes above related to the heliocentric model of planetary motion are labelled– A) ACF– B) BCF– C) ADE– D) BCE
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• Throughout time, people have created stories and proposed theories about space. The aboriginal people are known for their legends that dealt with– A) descriptions of planets– B) the formation of star constellations– C) prediction of comets– D) explanations of space travel
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• Four scientists and their contribution to the study of space are listed below– 1. Kepler proposed that the planets revolve around the sun in
an elliptical orbit– 2. Aristotle proposed that Earth is in the center and all the
planets revolved around the Earth– 3. Galileo used the telescope to confirm the sun-centred model
of planetary movement– 4. Copernicus proposed the ‘heliocentric model’ of planetary
motion
Listed from the earliest contribution to the most recent contribution, the order is
________ ___________ _________ __________
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• Calvin is setting up a model of the solar system. He positions a cardboard sun at one end of a school hallway and Pluto at the other end, 20 m away.
• Calvin knows that Pluto is 39.5 AU from the sun and Jupiter is 5.27 AU from the sun
• In order to make his model to scale, how many meters from the cardboard sun should Calvin place Jupiter? (record your answer to two decimal places)
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Homework!
• P. 376– 4-7
• P. 383– 5-7
Scale model of the solar system1) Need 10 people!
2) Each member chooses to represent the Sun or one of the nine planets
3) The ‘Sun student’ stands in one place. S/he calls out each planet name in turn, plus the number of steps that the ‘planet student’ must take from where the Sun is standing. Each step should be about 1 m long
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Planet Number of steps from the Sun
Mercury Less than 0.4
Venus 0.75
Earth 1
Mars 1.5
Jupiter 5
Saturn 9.5
Uranus 19
Neptune 30
Pluto 39.5
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