Stephen Hawking - Formation of the Solar System

Professor Stephen Hawking explains how the Earth and solar system were formed.

Into The Universe With Stephen Hawking - The Story of Everything

This video belongs to Discovery Communications and is being used for educational purposes only.

NARRATOR: Our solar system,
the place we call home,

lies about 26,000 light
years from the center

of our galaxy, the Milky Way.

Or, around 2/3 the way out.

The story of how these
huge planets came

to be orbiting an average yellow
star is six billion years long.

And since we don't
have that much time,

I'll speed it up a bit.

It starts with a bang.

Long ago, an ancient star
exploded, littering space

with swarming clouds
of the materials it

had made while it
lived, and the heavier

metals it created as it died.

We know this, because we can
see similar fields of dust

out in space today,
they are called nebulae,

and they are very beautiful.

Every nebula is different,
and in our case,

the clouds contained nitrogen,
and oxygen, and iron,

and silica, and all
the other stuff needed

to build a world like ours.

Then, the tireless
force of gravity

started to put it
all back together,

and the heavy engineering
that produces planets began.

Vast, spirals of
dust began to fall.

And at the center
of one of these,

a rocky planet called Earth
started to take shape,

built of star dust and
assembled by gravity.

Fast forward 100
million years, and it

had grown into a giant
ball, sweeping up billions

of tons of celestial debris.

This is where the Earth
from, and therefor,

how you and I began.

But our planet
would have remained

at large, sterile ball
of rock, and metal,

and minerals forever were it
not for one more event, one more

expression of the
forces of nature.

93 million miles away, at the
heart of the giant nebula,

the pressure and temperature
of a ball of hydrogen gas

had become so great that the
atoms were beginning to fuse.

A new star, our sun,
was coming to life.

As the sun ignited, it gave
off a huge blast of solar wind;

a radio active gust of energy.

This blew all the
remaining dust and gas

that was left over
from the nebula

out to the edge of the solar
system, which is why everything

is nice and orderly today.

In the outer reaches
of the solar system,

we have the huge gas planets;
Jupiter, Saturn, Uranus,

and Neptune.

Further in, are the
denser, rockier planets;

Mercury, Venus, Mars,
and, of course, the Earth.

Lucky for us, the sun
is 865 thousand miles

in diameter, or
just the right size

to burn consistently for a very
long time, eight billion years.

Long enough to allow
the next development

to take place; life.