Astro Physics Interview Preparation Guide

Sun is a luminous body whereas earth and moon are
non-luminous bodies. Only those parts of moon on which light
of sun falls is visible. Also sun is larger than, both the
each and the moon so that shadows of both are cast in space
with a distinct umbra and penumbra. These shadows? are
called eclipses.

The planets:- We know in the solar system that the sun is
fixed and that moving round it are a number of large
spheres known as planets . These are nine planets, viz., the
Earth, Neptune, Pluto, Uranus, Saturn, Jupiter, Mars and Mercury

The Moon:- It is the only natural satellite if the earth
revolving round the earth. It s one revolution round the
earth tales approximately one lunar month(of 29 ? days).
This period varies by 13 hours sue the eccentricities of the
orbits of the moon and earth. Unlike the sun and the stars,
its shinning is seen due to the reflected light which comes
from the sun. The diameter if the moon is lesser than one
quarter that of the earth. Compared with the sun the moon is
quite near to the earth(only 240,000 miles away). The
diameter of the moon on several calculations found to be
2160 miles.

The star is made up of dust and gas in space.
Basically it has so many stages
they are
1.black hole
2.nuetron star
3.supernova
4.red giant stage
our solar system consists a big star name sun which is
attracting 8 other planets with it's gravity.
It has an expected age of 10 billion years.

The sun:- Sun the brightest object in the sky. It is body id
the solar system. It has a luminous sphere approximately
8,65,000 miles in diameter. It is supposed that is consists
of a liquid inner portion with a gaseous outer covering. All
kinds of the life on the earth and on other members of the
solar system depend directly or indirectly upon the
radiation from the Sun

The average distance of the earth
from the sun is about 93,000,000 miles. If we compare the
great size pf the sun with the earth, to do so we have to
represent the earth by the head of a pin struck in the
teacher?s desk, the sun would be shown by a big ball at the
other end of the class ?room. Spectral analysis shows that
sun is compose id many elements such as found in the earth .
It s surface temperature is about 6,0000C. The volume of sun
is 13,000,00 tines that of the earth and its mass is 3
,32,0000 times that of the earth.

the distance of the earth from the moon is 2,40,000 miles or
24 x 104 miles and that from the sun is 93,000,000or93x106miles.

The moon is more than one light
second and the sun 8 light minutes away, i.e. light
traveling at 1,86,000 miles per second takes just over a
second to reach from the moon and about 8 minutes from the sun.

Magnetic effect of the earth. The earth behaves as it has
got a big magnet, running as mot a big magnet, running
almost from its north to south pole inside it (the earth).
Its south pole lies towards the geographical north pole and
the north pole lies towards the geographical south pole. As
a matted of fact, there is no such magnet inside it, but our
earth, as a whole, acts as a big magnet, we can prove this
fact with the help of the following experiments.

(1) one can magnetise iron
?rods by the earth. This is possible only when the earth
behaves like magnet or it has got magnetic material (a big
magnet) inside it.

(2)when we suspend a magnet.
Freely, it always rests in a particular direction almost
coinciding with the north and the south direction. It is
only possible when we presume that there is magnet inside
the earth of which north elope is towards soothe pole of
geography and south pole is towards geographical north pole.

The earth and its weight. It is impossible to find out the
weight of the earth by any type of balance. If we express it
in tons, the number of zeros required to do so would occupy
almost more than half of a volume of this book. Therefore,
we will try to express it in a simpler way as follows.

Take an example of hollow ball of the same size as the earth
consisting entirely of water (i.e. a solid ball of water).if
we weigh this ball we find this 5 1/2times lighter than that
of the weight of the earth. This is actually means that the
relative 5 1/2 or 5.5.

The equatorial diameter. The equatorial diameter of the
earth is 7920 miles in length and polar diameter is about 27
miles shorter than the former.

Shape and size of the earth. The shape of the earth is
regarded as a sphere , but it is actually an oblate spheroid
like as egg being slightly flattered at the poles