The Sun “A medium-sized star”

The Sun emits different forms of radiation across the electromagnetic spectrum. The EM spectrum consists of radiowaves, microwaves, infrared rays, visible light, ultraviolet rays, X-rays, and gamma rays. Almost all of the energy that reaches Earth’s surface comes from the Sun. This energy is the driving force behind our weather and climate and provides the energy needed to sustain life on Earth.

What is nebulae? Nebulae are vast clouds of gas and dust. The starting material of all stars. Gravity works to pull in this material. The accumulating gases cause the temperature and pressure in the centre to rise.

What is fusion? When the core temperature of the star reaches 10, 000, 000 to 15, 000, 000 ⁰ C, nuclear fusion, the transformation of H atoms into He atoms begins and the star turns “on”.

The Structure of the Sun The Sun is composed of many layers of gas, mostly hydrogen and helium. Nuclear fusion reactions happen in the core and “power” the Sun. The energy released in the fusion process works its way through the successive layers until it reaches the photosphere, the region from where the Sun’s light originates.

The Sun’s Surface Solar Prominences These are spectacular streamers of glowing gas that arch into space. They can be kilometers long and last for weeks at a time. Sun spots and Solar flares Some regions on the Sun are cooler and therefore appear to be darker than their surroundings. These are known as sun spots. Near them, violent outbursts called solar flares erupt, sending streams of high-energy sub-atomic particles into space.

The Sun’s Effect on Earth Remember that the Sun is basically a rotating, swirling ball of gas. This motion causes solar winds to form. Sometimes if solar winds are strong enough and travel toward Earth a beautiful display of light in the night sky can be seen. These colourful displays of light are known as the “aurora borealis” or the “northern lights”.