The Great Barrier Reef is the world\’s largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,600 kilometres (1,600 mi). It is located in the Coral Sea, off the coast of Queensland in north-east Australia. The world’s largest coral reef is the only living entity that is detectable from outer space. New research shows it is also in steep decline, with half of the reef vanishing in the past 27 years, caused by various factors, including cyclones, coral bleaching and the Crown of Thorns starfish.

credit: Paul from www.Castaways.com.au

Solar System includes the Sun together with the eight planets and their moons, the dwarf planets (Eris, Pluto, and Ceres), the asteroids, comets and other celestial bodies that orbit the sun. Pluto, known as the 9th planet, it is no longer recognised as one of the planets in the solar system. The four planets closest to the sun, Mercury, Venus, Earth, and Mars, are called the terrestrial planets because they have solid rocky surfaces. The four large planets beyond the orbit of Mars, Jupiter, Saturn, Uranus, and Neptune, are called the gas giants. Solar comes from a Latin word SOL meaning sun. The solar system was formed about 4.6 billion years ago.

credit: edwardyanquen

Mercury  (Diameter: 4879.4 km)

Venus  (Diameter: 12103.6 km)

Earth (Diameter: 12742 km)

Mars  (Diameter: 6779 km)

Jupiter  (Diameter: 139822 km)

Saturn  (Diameter: 116464 km)

Uranus  (Diameter: 50724 km)

Neptune  (Diameter: 49244 km)

credit: chrismeller

credit: edwardyanquen