SPL RF Aug 2021

Our Sun was created 4.6bn years ago from the collapse of a giant molecular cloud (1). As the GMC collapsed it formed a protoplanetary disc (2). With further collapse, the disc formed planets (not shown) and the centre became a T-Tauri star (3), cooler and redder than now. Eventually the Sun began to convert hydrogen into helium in its core, starting on the main sequence. (4). Some 4.5bn years later, this is where the Sun is today. As it ages, the sun expands and cools, and in around 5bn years it will be 2-3 times its current radius - a subgiant (5). Shortly after that it expands to become a red giant, around 200 times its current diameter (6, not to scale). Finally, the Sun will start to lose it outer atmosphere (7) and transform into a planetary nebula (8). Once this has dissipated into space, within around 10000 years, only the inert core of the Sun will remain - a white dwarf (9)