You might have noticed that the Earth is
round (it’s a spheroid, if you want to get
technical). So are the other planets in our
solar system. And so is the Sun. Are you
starting to spot a pattern here? But is there a
valid reason for this or does nature simply
have a thing for spheres?


The simplest answer points to one reason –
gravity. Each object has its own gravitational
field – the larger the object, the stronger the
field. Objects like stars and planets exhibit
very strong gravitational forces. When they
are being formed , all of the matter that goes
into them is pulled towards the center with
equal force and that results in a sphere. It
might happen gradually at a slow speed but
it still happens eventually. That’s why even if
a planet would somehow have another shape
like a pyramid or a square, gravity would pull
all the corners towards the center of the
planet until they eventually collapse.


Then what about moons and asteroids? They
are celestial objects and they can come in
weird shapes and sizes. Here is Mars’ moon
Phobos and it’s not round at all. It all comes
down to how strong their force of gravity is.
Like we said, larger objects have stronger
gravitational fields so it could simply be that
these moons and asteroids don’t have the
size required in order to generate a
gravitational force strong enough to pull
apart their matter and form it into spheres.


If you look at the largest moons in our solar
system like Titan, Ganymede, Io and even our
own Moon, you’ll notice that they are all
spheres while smaller moons like Phobos or
Hyperion haven’t bulked up to the required
size yet. But what is the size where celestial
objects start to shape themselves into
spheres? Approximately one fifth the size of
our planet.


And just to be clear, planets are not perfect
spheres because there are other factors at
play which influence their shape. Earth, for
example, bulges at the equator because of its
spin. The topology that naturally forms on
planets leads to the development of
geographical features like mountains,
volcanoes etc. This means that they might
look like perfect sphere from far away, but
get close enough and you can see their
surfaces are not smooth.

na God

Because its round,simple!