Download Unit 2. The planets in the Solar System The Solar System: Consists

Unit 2. The planets in the Solar System
1.
The Solar System:
Consists of a central star, the Sun, and several other
bodies bound by gravity that move around the Sun. The
bodies include planets, dwarf planets, satellites and
another small bodies.
Among the planets, we can distinguish between the inner
and the outer planets:

The inner planets, are also called terrestrial
planets, are the nearest planets to the Sun.
They have a rock composition. They are Mercury,
Venus, The Earth and Mars.

The outer planets are the farthest planets
from the Sun. they consist mainly of gas. They
are Jupiter, Saturn, Uranus and Neptune.
2.
About our planet:
The Earth is a rocky , almost spherical planet.
Its radius is 6.373 Km.
The Earth s formed by four spheres:

The Atmosphere surrounds the Earth and is the
outer sphere and lightest sphere of all, It is formed by a
mixture of gases, called air.

The Hydrosphere is all the water on the Earth:
oceans, seas, lakes, rivers, subterranean water, etc. Water
covers three quarters of our planet.

The Geosphere is the solid sphere, although in some
parts it can be viscous due to to its high temperature. It is
formed by mineral rocks and metals. It has three layers:
the crust, the mantle, and the core.

The Biosphere is the living beings which inhabit the
Earth and which live in three other spheres.
3.
The Earth’s movements
The earth makes two types of regular movement: rotation
and revolution
Rotation, occurs when the Earth spins on its axis every 24
hours
Revolution, the Earth makes a full orbit or revolution
around the Sun in 365 days, 6 hours and 9 minutes
A sidereal year is the time it takes the Earth to orbit
around the Sun
4.
The Earth’s satellite : The Moon
The Moon travels around the Earth once every 29,8 days.
The Moon has not atmosphere
There are maria and craters on the surface of the Moon
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Unit 2. The planets in the Solar System
The Moon has four phases: new moon, full moon, waxing
crescent and waning crescent
Effects of the Moon on teh Earth:
. Eclpises happen when the Earth, the Moon and the Sun
are in a straight line.
. Tides are an effect of the gravitacional atracción of the
Moon and the Su non the Earth
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