Page 16 - Karan Yadav - MYP Year 1 Physical Science Booklet

Sun - The Sun is the star at the centre of the Solar
System. It is a nearly perfect sphere of hot plasma.

t is by far the most important source of energy for
life on Earth. Its diameter is about 1.39 million
kilometres (864,000 miles), or 109 times that of
Earth, and its mass is about 330,000 times that of

Earth. It accounts for about 99.86% of the total
mass of the Solar System. Sun is 27,200 light years away from Earth.
The sun is 4.6 billion years. The Sound of the Sun has been re recorded

by NASA and can be heard below. The sound is a very low frequency.

Sun’s zones – The Sun is composed of three inner and four

outer layers. The inner layers are the core, radiative zone,
and convection zone, while outer layers are the
photosphere, the chromosphere, the transition region,

and the corona.

Core - The core is the Sun’s middle region where energy is generated
through thermonuclear reactions which creates extreme temperatures
of about 15 million degrees Celsius.

Radiative Zone - This zone is amidst the core and the convective zones,

and it is roughly 70 percent of the Sun’s radius. Energy produced
through nuclear fusion in the core moves steadily outwards. In this
zone, energy is carried outwards through radiation by photon carriers

in a process where it bounces many times through zigzagging paths.

Convection Zone - This layer of the sun is above the radiative zone and
it is the outer most layer of the Sun’s interior. It stretches from depths

of roughly 200,000 kilometres right up to the visible surface.
Temperatures at the bottom of the convection zone are about 2 million
Celsius. Energy moves towards the sun’s surface through convection
currents of heated and cooled gas. This happens when the density of
the radiative zone gets becomes low enough, and the energy from the

core in light form, is converted to heat.

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