The Sun viewed from Earth The Sun is basically the source of all the weather on Earth. It is about 150 000 000 km from Earth. It is actually a star. It takes about 8 minutes and 20 seconds for light to travel from the Sun to the Earth. The core of the Sun consists mainly of hydrogen, the lightest element. Thermonucleus reaction in the Sun causes it to release energy in the form of heat and light. In this reaction hydrogen atoms are combined into helium atoms. The Earth rotates around the Sun. This was thought first by Nicolaus Copernicus and later proved by Johannes Kepler a few centuries ago. Areas near the equator are heated more compared to areas near the two poles. As different colours of vegetation and landscapes absorb and reflect different amounts of light, some areas are warmer than others. For example snow on a mountain reflects a lot of light so very little heat remains. However in a tropical rain forest, the leaves that are green absorb lots of light and heat and exchange carbon dioxide for oxygen during the day.