Any object in space is called a celestial body.
E.g. – Planets, Moons, Sun, Stars etc.
Any celestial body orbiting around a planet or star is called a satellite. There are two types of satellites.
1) Artificial satellites (Man-made satellites)
2) Natural satellites
The Moon is a natural satellite. Some planets have many moons, but the Earth has only one moon. Moon is also called ‘Luna’.
The luna has no light or heat of its own. But it shines in the night sky by reflecting the light of the Sun. The part of the luna facing the sun is lit up. The part facing away from the sun is in darkness.
The luna(moon) is smaller than the Earth, and very much smaller than the Sun.
The luna is much closest to Earth than the Sun.
1) There is no atmosphere on the luna .
E.g. – The astronauts who landed on the luna(moon) had to wear airtight spacesuits with oxygen inside, supplied bottles on their backs.
2) Sounds cannot travel on the moon because there is no air.
E.g. – The astronauts who landed on the luna could talk to each other only through their radio sets.
No, we can’t. The luna always seems to change its shape. But the luna does not really change its shape. So, what happens to it?
The shape of the luna seems to change because the luna orbits the Earth (goes around the Earth).
The moon takes just over 28 days to go around the Earth once. (We say the moon orbits the Earth once every 28 days)
The changing shape of the bright part of the Moon that we see is called its phase.
1) The phases of the Moon depend on its position in relation to the sun and Earth.
2) As the Moon makes its way around the Earth, we see the bright parts of the Moon’s surface at different angles called ‘phases’ of the Moon.
The phases of the moon work in a cycle starting with the new moon.
The number of days between one new moon and the next new moon is 29 1/2 days.
1) The new moon is seen when the moon and the sun are on the same side of Earth.
2) The moon is between the sun and the Earth.
3) We see the side which is not lit, so the moon is dark.
4) We can’t see a New Moon because the lit side is facing directly away from the Earth.
5) The New Moon rises at dawn and sets at sunset.
1) The Full Moon is when the Earth is between the sun and the moon.
2) A Full Moon is the only moon phase that shines the whole night through.
3) A Full Moon rises at sunset and sets at sunrise and is visible all night long from moonrise to moonset.
4) It can be seen in the South near midnight.
The rise and fall of ocean water which happen due to the gravity or pull of the moon and the Sun. Tides can move the seawater from place to place.
1) High tides
2) Low tides
Every twelve hours the tides rise and fall without the level of water changing. As the Earth and moon spin, gravity pulls them together and the moon pulls the ocean water right beneath (under) it, causing it to rise and fall. When it is high tide on one side of the Earth, it will be low tide on the other side.
Twice each day, the level of the ocean rises and water covers the shore. We say that the tide is ‘in’. This is called ‘high tide’. High tide brings deep water to harbours and ports so that the ships can sail in and out. High tide may cause flooding.
Twice each day, the level of seawater falls. The seashore is uncovered. We say the tide has ‘gone out’. This is called ‘low tide’.
These tides occur twice a month. When the Sun and the Moon are both on the same side of the Earth these tides are occurred.