The Solar System (Space)

The Solar System:The Solar System:our corner of the Universeour corner of the Universe

http://www.nasa.gov/images/content/136063main_bm4_high.jpg

http://www.nasa.gov/images/content/136063main_bm4_high.jpg

The Solar SystemFor thousands of years ancient astronomerssaw points of light that appeared to move

among the stars. They called these ‘planets’,meaning ‘wanderers’, and named them after theRoman gods. If you look up at a clear night sky,you too will be able to see many of the planetsthat the ancient astronomers saw. You might

also see an assortment of space junk and satellites thatalso move in the night sky.

Theories of the solar system

•Pythagoras a Greek scientist who lived in the sixth century BC suggested that the Earth was the centre of the universe

•Aristotle (384–322 BC), Hipparchus (died after 127 BC) and Ptolemy (127–145 AD) proposed more detailed models in which Earth was placed at the centre of the solar system

•This type of model is known as the geocentric (geo-earth) or Ptolemy model

Geocentric Model

http://en.wikipedia.org/wiki/Image:Ptolemaicsystem-small.png

http://en.wikipedia.org/wiki/Image:Ptolemaicsystem-small.png

Geocentric Model

Science Focus 1: Coursebook

Theories of the solar system

•Another ancient Greek, Aristarchus (310–230 BC) questioned the geocentric model and proposed a model where the Earth and other planets revolved around the Sun

•This is known as a heliocentric model (helio = Sun)

•The geocentric model continued to be favoured until the end of the fifteenth century

• In the 1530s, Polish astronomer Nicolas Copernicus (1473–1543) agreed with Aristarchus

Heliocentric Model

http://en.wikipedia.org/wiki/Image:Heliocentric.jpg

http://en.wikipedia.org/wiki/Image:Heliocentric.jpg

Heliocentric Model


Theories of the solar system•Galileo (1564–1642) was a strong supporter of Copernicus’s

ideas, in 1609 he used a telescope for the first time to make detailed observations of the Moon and planets; his observations exposed errors in the geocentric model

•Tycho Brahe (1546–1601) didn’t support the heliocentric theory and took numerous detailed measurements of the positions of stars and planets in an attempt to improve the geocentric model

•Using Brahe’s data, German astronomer Johannes Kepler (1571–1630) finally showed the heliocentric model was correct

The solar system•The term ‘solar system’ takes its name from the object at the

centre of it all—the Sun, also known as Sol

•The nine planets of the solar system, in order starting from closest to the Sun, are: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto* (*now known as a dwarf planet)

•A mnemonic device to remember the order could be: My Very Elegant Mother Just Served Us Nine Pizzas

•What is your mnemonic device?

The solar system

•The planets each orbit the Sun, rotating on their axes as they do so

•The time taken for a planet to spin once on its axis is called its day, and the time taken to orbit the Sun once is called its year

•All the planets have days and years of different lengths

How the planets move

•The four innermost planets are called terrestrial (meaning ‘Earth-like’) and orbit the Sun in almost circular orbits

•The larger outer planets—Jupiter, Saturn, Uranus and Neptune—are known as the gas giants (or Jovian planets), because their outer layers are composed of gases such as hydrogen and helium, and they move in elliptical or oval orbits

•All planets move in the same plane (a large imaginary flat surface) except for Pluto, whose orbit is tilted by about 17° compared to the other planets’ orbits

http://solarsystem.jpl.nasa.gov/multimedia/gallery/vis_orb.jpg

http://solarsystem.jpl.nasa.gov/multimedia/gallery/vis_orb.jpg

http://solarsystem.jpl.nasa.gov/multimedia/gallery/outer_orb.jpg

http://solarsystem.jpl.nasa.gov/multimedia/gallery/outer_orb.jpg

Sun

http://en.wikipedia.org/wiki/Image:Sun920607.jpg

MythologyThe Sun God. Greeks Called it

Hellos

Mass333 400 times the mass of the

Earth

Diameter1 392 000 km (109 x Earth’s

diameter)

Gravity 28 times that on Earth

Surface Temperature

6000°C (average). From 4500 to 2000000°C up to 15000000°C in

the core.

Period of rotation (day)

Equator 26 Earth days, poles 37 Earth days

Tilt of axis 122°

http://upload.wikimedia.org/wikipedia/commons/a/aa/Sun920607.jpg

Mercury

http://en.wikipedia.org/wiki/Image:Reprocessed_Mariner_10_image_of_Mercury.jpg

MythologyGod of travel, commerce and

thieves

Mass 0.056 times that of Earth

Moons None

Diameter4878 km ( = 0.38 x Earth’s

diameter)

Surface Similar to Earth’s moon

Gravity 0.38 times that on Earth

Surface Temperature

–170°C to 430°C


59 Earth days

Tilt of axis 0°

Distance from Sun0.39 AU (58 million

kilometres)

Time to orbit Sun (year)

88 Earth days

http://en.wikipedia.org/wiki/Image:Reprocessed_Mariner_10_image_of_Mercury.jpg

Venus

http://en.wikipedia.org/wiki/Image:Venus-real.jpg

Mythology Goddess of love and beauty


Moons None

Diameter12 103 km ( = 0.95 x Earth’s

diameter)

Surface Extensive cratering, volcanic

activity.


Surface Temperature 460°C


243 Earth days

Tilt of axis 30°


kilometres)


225 Earth days

http://en.wikipedia.org/wiki/Image:Venus-real.jpg

Earth

http://en.wikipedia.org/wiki/Image:The_Earth_seen_from_Apollo_17.jpg

Mythology Gaia—mother Earth

Mass1.0 times that of Earth (5 980 000 000 000 000 000 000 000

kg)

Moons One (‘the Moon’)

Diameter 12 756 km

SurfaceTwo-thirds water, one-third

land


Surface Temperature

average 22°C


1 Earth day

Tilt of axis 23.5°

Distance from Sun 1 AU (150 million kilometres)

Time for light to reach Earth

8 minutes


365.25 Earth days

http://en.wikipedia.org/wiki/Image:The_Earth_seen_from_Apollo_17.jpg

Mars

http://en.wikipedia.org/wiki/Image:2005-1103mars-full.jpg

Mythology God of war


Moons 2 (Phobos—diameter 23 km,

Deimos—diameter 10 km)

Diameter 6794 km ( = 0.53 xEarth’s

diameter)

Surface

Soft red soil containing iron oxide (rust). Cratered regions,

large volcanoes, a large canyon and possible dried-up

water channels.


Surface Temperature

–120°C to 25°C


1.03 Earth days

Tilt of axis 25.2°


kilometres)


687 Earth days

Time to reach Mars 9 months

http://en.wikipedia.org/wiki/Image:2005-1103mars-full.jpg

The terrestrial planets

http://solarsystem.nasa.gov/multimedia/gallery/terr_sizes.jpg

http://solarsystem.nasa.gov/multimedia/gallery/terr_sizes.jpg

Jupiter

http://en.wikipedia.org/wiki/Image:Jupiter.jpg

Mythology Ruler of the Gods

Mass 318 times that of Earth

Moons

At least 28 moons and four rings, including the four

largest moons: Io, Ganymede, Europa and Callisto. These are

known as the ‘Galilean’ moons.

Diameter142 984 km ( = 11.21 x

Earth’s diameter)

Surface Liquid hydrogen


Surface Temperature

Cloud top –150°C


9 hours 55 minutes

Tilt of axis 3.1°


kilometres)


11.8 Earth years

http://en.wikipedia.org/wiki/Image:Jupiter.jpg

Saturn

http://en.wikipedia.org/wiki/Image:Saturn_from_Cassini_Orbiter_%282007-01-19%29.jpg

Mythology God of agriculture


MoonsAt least 30 moons and rings in

seven bands

Diameter120 536 km (= 9.45 x Earth’s

diameter)

Surface Liquid hydrogen


Surface Temperature

–180°C


10 hours 39 minutes

Tilt of axis 26.7°


kilometres)


29.5 Earth years



Uranus

http://en.wikipedia.org/wiki/Image:Uranusandrings.jpg

Mythology Father of Saturn


MoonsAt least 21 moons and 11

rings

Diameter51 200 km (= 4.01 x Earth’s

diameter)

SurfaceLikely to be frozen hydrogen

and helium


Surface Temperature

–220°C


17 hours 14 minutes

Tilt of axis 98°


kilometres)


84 Earth years

http://en.wikipedia.org/wiki/Image:Uranusandrings.jpg

Neptune

http://en.wikipedia.org/wiki/Image:Neptune.jpg

Mythology God of the sea


Moons 8 moons and 5 rings

Diameter49 528 km ( = 3.88 x Earth’s

diameter)

Surface Frozen hydrogen and helium


Surface Temperature

–220°C


16 hours 7 minutes

Tilt of axis 29.3°


kilometres)


165 Earth years

http://en.wikipedia.org/wiki/Image:Neptune.jpg

The gas giants

http://solarsystem.jpl.nasa.gov/multimedia/gallery/gas_sizes.jpg

Pluto (dwarf planet)

http://en.wikipedia.org/wiki/Image:Pluto.jpg

Mythology God of the underworld


Moons 1 (Charon)

Diameter2300 km ( = 0.18 x Earth’s

diameter)

Surface Icy crust of methan


Surface Temperature

–223°C


6 Earth days

Tilt of axis 122°


kilometres)


249 Earth years

In July 2015 (10 years after launch) the New Horizons spacecraft will capture the first up-close imagery of Pluto, its

moons and a region of the outer solar system called the Kuiper Belt.

Eris (dwarf planet)Eris (centre) and Dysnomia (left of centre).Discovered

January 5, 2005, from images taken on October 21, 2003

Mythology Greek goddess of strife

Mass

Moons 1 (Dysnomia)

Diameter 2600 km (± 400 km)

Surface

Gravity

Surface Temperature

−243 and −217 degrees Celsius


> 8 h?

Tilt of axis

Distance from Sun 37.78 AU to 97.56 AU


556.7 Earth years

http://en.wikipedia.org/wiki/Image:Eris_and_dysnomia2.jpg

http://www.solarviews.com/cap/misc/obliquity.htm

Comparing tilt of axis

The planets to scale. The rings of the gas giants are not shown.

http://solarsystem.jpl.nasa.gov/multimedia/gallery/solarsys_scale.jpg(Distance between objects not to scale)

How small are we?

source: Celestia (application)(Distance between objects not to scale)

Earth

Earth

How small are we?

source: Celestia (application)(Distance between objects not to scale)

Relative distance of planets• Sun = 1300mm

diameter (blown up garbage bag)

• Mercury = 4.5mm (coffee bean) 54m from Sun

• Venus = 11.3mm (small blueberry) 101m from Sun

• Earth = 11.9mm (small blueberry) 139m from Sun

• Mars = 6mm (pea) 213m from Sun

image source: Google Earth

Relative distance of planets• Jupiter = 133.5mm

(large grapefruit) 727m from Sun

• Saturn = 112.5mm (large orange) 1332m from Sun

• Uranus = 47.7mm (Kiwi) 2681m from the Sun

• Neptune = 46.2mm (nectarine) 4200m from the Sun

• Pluto = 2mm (grain of rice) 5522m from the Sun

image source: Google Earth

Earth’s movement in spaceThe ancient civilisations defined the days, seasons,

months and years by following the movements of the Sun and Moon. Babylonians, Mayans, indigenous

Australians and many other cultures all developed complex ways to predict seasonal changes. This

enabled people to plan when to plant crops or move to a new location in search of seasonal foods. Survival depended on this ancient scientific knowledge of the

Earth’s movement in space.

Earth’s movement in space

• The earth spins on its axis, causing alternating day and night

• When Earth is in the position shown, days are shorter in the southern hemisphere and longer in the northern hemisphere.


Earths movement in space: one year

• The time taken by a planet to orbit (travel around) the Sun is called a year.

• Earth spins on its axis while it orbits the Sun

• The Earth spins once on its axis in a day, and takes a year to orbit the Sun.


Earths movement in space: seasons

• As the Earth orbits the Sun, the tilt causes different parts of the Earth to experience different heating effects

• At the summer solstice, days are longest, and at the winter solstice, days are shortest.

• Between these two times, at the two equinoxes, day and night are of equal length.


Aboriginal seasons

•Bininj/Mungguy (local Aboriginal people) recognise six seasons in the Kakadu region:

•Gunumeleng - Pre-Monsoon Storm Season

•Gudjewg - Monsoon Season

•Banggerreng - Knock 'em down storm Season

• Yegge - Cooler but still humid Season

• Wurrgeng - Cold Weather Season

• Gurrung - Hot Dry Weather

http://www.environment.gov.au/parks/kakadu/artculture/seasons.html

We choose to go to the moon. We choose to go to the moon in this decade and do the other things, not because they are easy, but because they are hard, because that goal will serve to organize and measure the best of our

energies and skills, because that challenge is one that we are willing to accept, one we are unwilling to postpone, and one which we intend to win,

and the others, too. (John F. Kennedy -- September 12, 1962)

The Moon

http://www.youtube.com/watch?v=e08r5IRTbjE

The MoonMythology God of the night


Diameter 3476 km ( = 0.27 x Earth’s

diameter)


Surface Temperature –230°C to 123°C


27.3 days

Tilt of axis 5°

Distance from Earth 384,403 kilometres

Time to orbit Earth 29.5 days

Time to reach Moon 3 days

Date first visited July 20, 1969

Notice that the time for the Moon to orbit the Earth is nearly the same as the time it takes to spin once on its axis—this

results in us only ever seeing the one side of the Moon from Earth. The other side is often called ‘the dark side of the Moon’

since it had never been seen until the Apollo missions.

What does the Moon do?

•The Moon has a great impact on life on Earth

• It changes appearance over the course of one Earth month

• It is responsible for the tides

• It is involved in solar and lunar eclipses

Phases of the Moon• The Moon takes about a month to orbit the Earth, and

spins at a similar rate, and therefore we always see the same face of the Moon. How much of the Moon’s face we see depends on where it is in its orbit around the Earth. We call these different views phases.

• Imagine yourself on the Earth, under point A looking towards Moon A. Because the Sun is directly behind the Moon, you see nothing of the Moon. Now imagine yourself on Earth under point C, looking directly towards Moon C. From here you would see only half the Moon.


The Moon and the tides

As early as the second century BC, the Chinese had recognised a connection between tides and the Moon’s cycle. About twice a day

the sea level rises to a high tide and falls to a low tide—the average time between two high tides is 12 hours 25 minutes. It was not until Newton proposed a theory of gravity in 1687 that

tides were understood to be the result of the Moon’s gravitational pull on the Earth.

The Moon and the tides•The gravitational force between two objects is only noticeable when one or both objects are very large, as is the case with the Moon and the Earth. The Moon attracts the oceans towards it, enough to cause a bulge in the oceans facing the Moon. If this were the only effect there would only be one high tide and one low tide a day, not two. The Earth’s rotation, however, causes a similar bulge on the other side of the Earth.


Solar eclipseThe word ‘eclipse’ comes from the Greek word for ‘abandonment’ — the eclipse was seen as the Sun

abandoning the Earth. There are three types of solar eclipses.

Solar eclipse• A - total solar eclipse is when the Sun is

covered by the Moon.

• B - annular solar eclipse occurs when the Moon is at its greatest distance from the Earth.

• C - partial solar eclipse is when the Moon covers only part of the Sun.

• All solar eclipses occur when the Moon comes between the Earth and the Sun and the Moon’s shadow falls on the Earth.

http://en.wikipedia.org/wiki/Image:Eclipses_solares.en.png

Solar eclipse, as seen from the International Space Station - March 29, 2006.

http://en.wikipedia.org/wiki/Image:Eclipse_fromISS_2006-03-29.jpg

QuickTime™ and aGIF decompressor

are needed to see this picture.

Solar eclipse

• On August 1, 2008 a total eclipse will be visible from a narrow corridor through northern Canada (Nunavut), northern part of Greenland, Siberian part of Russia, western Mongolia, and China.

Lunar eclipseA lunar eclipse occurs whenever the Moon passes through some portion of the Earth's shadow. This can occur only when the Sun, Earth, and Moon are aligned exactly, or very closely so, with the Earth in the middle. Hence, the Moon is always full during a lunar

eclipse. A lunar eclipse occurs at least two times a year, whenever some portion of the Earth's shadow falls upon the Moon.

Lunar eclipse•The Moon does not completely disappear as it passes through the umbra because of the refraction of sunlight by the Earth's atmosphere into the shadow cone; if the Earth had no atmosphere, the Moon would be completely dark during an eclipse. The red colouring arises because sunlight reaching the Moon must pass through a long and dense layer of the Earth's atmosphere, where it is scattered.


On August 28, 2007 a total lunar eclipse will be visible in its entirety for all of Eastern Australia and New Zealand. The partial eclipse begins at 18:51, and the total eclipse

occurs from 19:52 until 21:22 (EST).

http://sunearth.gsfc.nasa.gov/eclipse/LEmono/TLE2007Aug28/TLE2007Aug28.html

The Solar SystemThe Solar System

• How long would it take How long would it take you to travel to Pluto?you to travel to Pluto?

• How far from Earth is the How far from Earth is the furthest manmade object?furthest manmade object?

• What would happen if we What would happen if we no longer had the Moon?no longer had the Moon?

• When is the next total When is the next total solar eclipse in Australia?solar eclipse in Australia?

ReferencesReferences

• NASA (2007). NASA (2007). NASANASA. URL: . URL: www.nasa.govwww.nasa.gov. (Accessed August 15 2007). (Accessed August 15 2007)

• Whalley, K., Phillips, G., Rickard, G., Monckton, S., & Robrson, P. (2005). Whalley, K., Phillips, G., Rickard, G., Monckton, S., & Robrson, P. (2005). Science Focus OneScience Focus One. . Sydney: Pearson Education Australia.Sydney: Pearson Education Australia.

• Wikipedia. (2007). Solar System. Wikipedia. (2007). Solar System. WikipediaWikipedia. URL:. URL:http://en.wikipedia.org/wiki/Solar_systemhttp://en.wikipedia.org/wiki/Solar_system. . (Accessed August 15 2007)(Accessed August 15 2007)

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