The Solar System


Universe - Big Bang

Universe = 14 Billion Years Old.

Solar system was created from a molecular cloud of dust and gas called a NEBULA.

CONTRACTION PHASE = the energy distributed over the large area begins to collapse and concentrates the energy and the mass in the centre. This happens due to gravity.

Due to the collapse everything rotates faster and the hydrogen in the centre begins to get hotter, this created our star which is made of helium and hydrogen and is a ball of gas with no core.

One Astronomical Unit = 150 millions kilometres (the distance from Earth to our sun).

Left over matter sticks together to form the larger bodies i.e. our planets = ACCRETION.

Remaining material can be hoovered up due to gravity.

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Inner Terrestrial Planets

All terrestrial planets are:

  • Small
  • A similar structure to Earth
  • Has a rocky solid surface made up of silicate rocks = silicon and oxygen
  • High density
  • Have a metallic core that is made mostly of iron
  • Has some kind of metallic core
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The Messenger of the Gods.

It is the planet closest to the sun.

It looks like the moon as it is heavily cratered due to having no meaningful gravity and therefore no protection from meteorites.

It has a weak gravitational pull as it is the smallest planet.

It has a large inner iron core - bigger than Earth's - meaning it also has a very strong magnetic field.

There is evidence of extinct volcanic activity.

It has a thin mantle and a thin crust.

Mercury was visited by unmanned probes - Mariner Probe and Messenger Probe.

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Goddess of Love. Morning Star.

Brightest object in the sky after our moon.

Similar size to Earth in mass and gravity.

Has a thick atmosphere of swirling clouds which hides the surface and reflects the sunlight = high ALBEDO.

Has a RUNAWAY GREENHOUSE EFFECT = very hot - has no water and a very poisonous and acidic atmosphere.
There is no plants - no photosynthesis - or rain meaning very high levels of CO2 that is released from volcanoes.

There is no tilt on the axis and therefore no seasons.

Unmanned probe in the 60's which identified 50,000 landforms that were identified as volcanoes.

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There is a powerful magnetic field which protects us from solar winds without it our atmosphere would be stripped away.

The Earth is mostly iron (mostly concentrated in the core) oxygen and silicon.

An impact early in Earth's history created a debris cloud which accreted to form our moon.

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LUNAR DAY and LUNAR YEAR are the same (28 days) meaning we only see one side of the moon from Earth.
Made of:

  • HIGHLANDS = light coloured igneous rock, oldest rocks on the surface, made of ANORTHOSITE which is also rich in a white mineral - PLAGIOCLASE FELDSPAR.
  • MARIA ("lunar seas") = dark coloured igneous, younger, made of BASALT which is solidified magma.

Lunar Exploration:
First man landed on the moon in 1969 (APOLLO 11).

They brought back samples of both the Maria and the Highlands.

There are earthquakes on the moon due to the friction created from the Earth's gravity pulling on it.

The gravitational pull of the moon is what gives Earth its TIDES - high tides and low tides - no moon = no tides.

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Has polar caps of water ice and frozen CO2.
Planet is rich in CO2 but has a thin atmosphere.

Has lots of IRON OXIDE on the surface which gives the planet it's red colour.

There is evidence of water flowing (rivers and seas) on the surface.

Mars once had a atmosphere as we have found meteorites sat on the surface without having exploded or creating a crater.

OLMYPUS MONS is a shield volcano - it is the biggest volcano in our solar system, measuring 3 times higher than Mount Everest.

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Outer Gas Giants

Gas giants all have:

  • A huge size
  • A low density
  • A solid core
  • Are made of liquid and gas
  • Have a large gravitational pull
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Largest planet in our solar system.

(Third brightest object in our night sky)

It rotates very fast so has the shortest day of only 9.9 hours.

It is mostly made of hydrogen and helium - has no solid surface only a thick windy atmosphere over an ocean of liquid hydrogen due to CORIOLIS FORCES.

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IO - Jupiter Moon

IO's surface doesn't have any craters and is therefore fairly young which means that it is volcanically active to be producing new surface.

It has a yellow hue due to SULPHUR from lava lakes 100 miles across.

Heat source = TIDAL HEATING.
This means that the source of heat is created due to Jupiter's strong gravitational pull which causes the moon to deform during its orbit and create friction, this allows it to be highly volcanic and is an extreme version of Earth's tides.
This also means that the moon will never lose its heat source as long as it stays in the same orbit.

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Europa - Jupiter Moon

Icy moon covering a liquid ocean.

It is likely to be volcanically active e.g. Springs like we see in Iceland and this leads to the possibility of life as our life on Earth originated in the oceans.

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Saturn has a ferocious windy atmosphere.

Its rings are made up of icy particles which have a high albedo and therefore very bright.

Saturn has the lowest density of all planets in our solar system - a density lower than water.

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Enceladus and Titan - Saturn Moons

Icy moon covering a liquid surface.

Has CRYOVOLCANISM - "tiger stripes" - it is due to tidal heating - liquid pockets of water at the surface which erupt due to pressure as GEYSERS before supercooling to form ice crystals.

Superficially quite Earth like.

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Smallest of the gas giants.

It is a icy planet.

The surface is a dense slush of water, methane and ammonia.

It is tipped over 90 degrees on its axis.

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Has a deep atmosphere of hydrogen and helium.

One year on Neptune equals 165 Earth years.

It has supersonic winds (fastest of all in our universe) and giant storms.

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Triton - Neptune Moon

CRYOVOLCANISM - has geysers of nitrogen gas and dus, with plumes that can reach 8km high.

TIDAL HEATING due to Neptune's gravity.

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