A Closer Look at the Objects of our Solar System

S1-4-08a Compare and contrast properties of the planets of our solar system.

KEY WORDSM V E Mo J S U N P Terrestrial Gas giantsAsteroid Belt Kuiper Belt

Outer region of nebula:• Gases (far from new Sun) begin to cool • Cluster together and condense• Forming the Gas Giants:

Jupiter, Saturn, Uranus and Neptune

Formation of our Solar SystemMatter recycled from past supernova explosions• Nebula made mostly of hydrogen and helium• Iron, rock and ice made up about 1%

Gas Giants appear to lack solid surfaces, but the gases may become liquid or solid deeper towards their dense core

Inner region of nebula:• Gases in the inner region too hot to condense• Chunks of iron and rock collide and stick together• Forming Terrestrial planets:

Mercury, Venus, Earth and Mars

Terrestrial planets are composed of rock, iron and hard elements through to the molten core

Nebula

Attracted by gravity, clustered together

• hydrogen and helium• Iron, rock and ice

Terrestrial planets(inner planets)

Closest to the Sun• Receives sunlight 10x brighter than Earth• Day temperatures over 400°C No atmosphere - so night temp fall to -180°C• Day (rotation) – 59 Earth days • Year (revolution) – 88 Earth days

Mercury

It rotates so slowly that its “year” is less than 2 “days” long

3rd brightest object in the sky • CO2 atmosphere traps heat (+ 465°C)• Many volcanoes eject tonnes of sulphur Clouds of sulphuric acid – makes acid rain• Day (rotation) – 243 Earth days • Year (revolution) – 225 Earth days

Venus Sun and Moon are brightest objects

Its “year” is shorter than its “day”

Atmosphere (N2, O2, H2O) stabilizes temperature• Ranges from -85°C to +65°C Liquid water covers about 70% of surface• Generally stable – some volcanoes, earthquakes• Day (rotation) – 1 Earth days • Year (revolution) – 365 1/4 Earth days

Earth

Distance from the Sun is most responsible for the factors that contribute

to Earth’s ability to sustain life

Bright red - iron oxide dirt makes it reddish• Most studied planet (no signs of life… yet ) Of all planets, Mars is most like Earth• Surface temp ranges from -120°C to +30°C • Day (rotation) – 1 Earth day • Year (revolution) – 687 Earth days

Mars

Although it is dry and barren now, scientists have evidence that may

point to past glaciers and liquid water

An Asteroid Belt separates the Terrestrial planets from the Gas Giants – maybe

remains of a totally smashed older planet

The Gas Giants(outer planets)

Look at the shadow of a moon on the picture of Jupiter

Largest of the planets (11x bigger than Earth).• Has 63 moons (2006) Great Red Spot is a continuous hurricane• Temp around -160°C• Day (rotation) – 10 Earth hours • Year (revolution) – 11.9 Earth years

Jupiter

The coloured bands are gas clouds being streaked over

the surface as it rotates quickly

3 moons and a shadow in this picture

• 2nd largest of the planets Least dense – may not have a solid core Rings stretch from Earth to Moon• 60 moons and 1000 rings (could be crushed moon)• Day (rotation) – 11 Earth hours • Year (revolution) – 29.5 Earth years

Saturn

Notice the coloured bands on the surface here too

Some kids on Earth didn’t know this photo

was being taken when they were

playing with laser pointers….

Rotates on its side• Extremely cold -210°C Has several narrow, dark rings• Has 27 moons• Day (rotation) – 17 Earth hours • Year (revolution) – 84 Earth years

Uranus

It is now pronounced “ur-an-is” not “ur-anus”

• Only discovered because its gravity “tugs” on Uranus’s orbit causing changes

Blue and white – methane in atmosphere The Great Dark Spot is a gigantic storm• Extremely cold -220°C• Day (rotation) – 16 Earth hours • Year (revolution) – 165 Earth years

Neptune

Neptune has some faint rings too, and 20 moons

Kuiper Belt • disc-shaped region of thousands of icy objects • Extends from Neptune to about 30 to 55 AU Pluto and Eris are the best known dwarf planets • even further - Oort Cloud (> 5000 AU)

Pluto was reclassified as a dwarf planet in 2006

• Orbit is squished – it crosses Neptune and is sometimes closer to Sun

No atmosphere – not a Gas giant• Extremely cold -220°C• Has 3 moons!• Day (rotation) – 6 Earth days • Year (revolution) – 248 Earth years

Pluto

Astronomers have found objects bigger than Pluto

orbiting the Sun

CAN YOU ANSWER THESE QUESTIONS?

S1-4-08a:How are the Gas Giants different from the Terrestrial planets?

What is unique about each planet?

KEY WORDSM V E Mo J S U N P Terrestrial Gas giantsAsteroid Belt Kuiper Belt