OUR UNIVERSE
The Universe is everything that exists, from the smallest particle on Earth to the vast galaxies of deep space. Every part of it, including space and time, came into existence in the Big Bang a huge explosion that occurred about 13.8 billion years ago. At that time, the Universe looked nothing like it does today, and it has been expanding, cooling, and changing ever since. The hydrogen and helium of the very young Universe formed stars, which in turn produced all the other elements in today's Universe, including those that make Earth and everything on it, including you.
THE GREAT START...
The Big Bang is considered as the start of the Universe. The Big Bang in the beginning the universe was unimaginably small, dense, and incredibly hot within a trillionth of a second it balloons from being smaller than an atom to bigger than galaxy it was made of tiny particles of energy that turned into particles of matter within three minutes the universe was made almost entirely of the nuclei of hydrogen and helium atoms.
FORMATION AND EVOLUTION
GALAXIES
A galaxy is a vast group of stars held together by gravity - it is thought that there could be some 2 trillion in our Universe. They are not scattered randomly but exist in clusters, vast distances apart. All the galaxies together take up just two millionths of space.
STARS
Stars are huge spinning balls of hot, luminous gas. Each one is unique because stars differ in colour, temperature, size, brightness, and mass. Over time, characteristics change and the star evolves from one stage of star life to another. The key to a star's life is its mass - the amount of gas it is made from. Mass determines the star's life span, as well as its other characteristics and how these change.
PLANETS
Long before the time of telescopes, ancient astronomers noticed that there were several bright lights that moved, over the course of many days, against the background stars. The ancient Greek name for these moving objects was "planets", meaning "wanderers".
