The Sun’s Size, Heat and Temperature After completing this section, students will explain nuclear fusion, and describe the sun and compare it to other stars (Standard PI – 071 and 072

Compared to the Earth, the Sun is enormous. The sun has a diameter of 1,400,000 kilometers (more than 3 times the distance between the earth and the Moon) The Sun could hold 1 million Earths If the sun went dark right now, it would take about 7 minutes for us to find out. It takes that long for the light to get to us

Despite all of these examples, the Sun is incredibly average It is of average size, average age and average temperature

The Sun and all other stars get their energy from fusion Fusion is the combining of the nuclei of lighter elements to form a heavier

In the core of the Sun, hydrogen in the form of plasma, combines to form helium. When this happens, heat and light are produced Plasma – fourth state of matter consisting of charged particles (atoms without electrons)

The Sun’s Layers

The Core The core contains mostly hydrogen and helium in plasma state. Temperatures in the core reach 15,600,600 degrees Celsius

The Radiation Zone This layer is made of plasma also, but much cooler than the core (2-8,000,000 degrees Celsius)

The Convection Zone Rising and falling currents of plasma carry energy to the Sun’s surface where it is radiated out into space as sunlight

The Photosphere This is the visible surface of the sun. The temperature of the photosphere is 6,000 degrees C.

The Chromosphere The inner layer of the Sun’s atmosphere, it extends thousands of kilometers above the surface of the sun

The Corona This is the thin outer layer of the Sun’s atmosphere. It has a temperature of 1-3,000,000 degrees Celsius

Features on the Sun

Granules - visible structures in the photosphere of the Sun arising from activity in the Sun's convective zone

A solar prominence is a large bright feature located in the solar corona Prominences are caused by the Sun’s magnetic field

A sunspot is a region on the photosphere that is marked by a lower temperature than its surroundings and intense magnetic activity

A solar wind is a stream of charged particles ( plasma) which are ejected from the upper atmosphere of a star

As the solar wind blows past the Earth, some particles interact with the Earth’s magnetic field These displays of color are called auroras