The Moon
There are many moons in our solar system, which orbit planets,
just like planets orbit the Sun. Earth has one Moon, Mars has
two small moons, Mercury and Venus don’t have any, while
Jupiter has at least 63! The Earth’s Moon is made up of rocks,
both solid and molten.
Quick Q’s:
1. Does our Moon have
a scientific name?
Astronomers call the
Earth’s Moon Luna,
to distinguish it from
the natural satellites
of other planets.
2. If the Moon is
cold and dark, how
does it give off light?
The Moon does not
give off light of its own.
It simply reflects the
sunlight that falls on it.
3. Why can’t we see the
Moon during the day?
During the day the
bright light of the Sun
blocks the soft glow
of light reflected by
the Moon.
4. What are spring
tides and neap tides?
When the Sun, the
Moon and the Earth
are in a straight line,
the gravitational force
of the Sun strengthens
that of the Moon
causing tides that are
higher than usual.
These are called spring
tides (although they
have nothing to do with
the season of Spring).
When the Sun and the
Moon are at right
angles to the Earth,
weaker tides, called
neap tides, are caused.
Tides are important to
wash away the debris off
the coasts.
Q Why is the Moon’s surface filled
with craters?
A The Moon does not have an
atmosphere. Therefore, meteors and
asteroids from outer space crash into its
surface making craters. Tycho crater, one
of the biggest lunar craters, is more than
85 kilometres (50 miles) wide.
Q What does the term ‘Blue Moon’ mean?
Blue Moon refers to the second Full Moon
to appear in a month. It is very rare indeed.
There are other definitions of Blue Moon as
well, but this is the most widely accepted
definition nowadays.
Q How does the Moon cause tides in
our oceans and seas?
A Tides are caused by the gravitational
force exerted by the Moon on our planet.
This force causes the ocean to bulge out in
the direction of the Moon, making the tide
rise. As the Earth is also pulled towards the
Moon, the ocean on the side facing away
from the Moon also bulges out. So it is high
tide there as well. In the region between the
two bulges (high tides) the water level
decreases, causing low tides. Tides are higher
in the tropics due to the bulge of the
equator. Many forms of life on the coast are
tailored to the cycle of tides.
Q Why does the Moon appear crescentshaped
at times?
A The shape of the Moon as seen from the
Earth keeps changing. The changing shapes
of the Moon are called phases. When the side
of the Moon that faces the Earth is turned
away from the Sun, we are unable to see the
Moon. This phase is called the New Moon.
As the Moon travels in its orbit around the
Earth, we start to see a small portion of the
Moon that is lit up by the Sun. This is called
the Crescent Moon. The lit up portion seen
by us slowly increases, and we see a Half
Moon, then a Three-quarter Moon. When
the Moon completes a half orbit around
the Earth, we can see the entire disc lit up
by the Sun – the Full Moon.
Crescent Moon
As the Moon orbits around the Earth, we see only a part
of it that is lit up by the Sun, depending upon the angle
made by the Earth, the Moon and the Sun.
High and low
The gravitational pull of the Moon on the Earth causes
tides in the oceans and seas of the Earth.
Spring
Tide
Sun High
Tide
High
Tide
Low Tide
Low Tide
Neap
Tide
Neap
Tide
Spring
Tide
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