What existed before the Big Bang? How our Universe was born from nothing or if there was something that existed before it remains a mystery, but that is not stopping some physicists from trying to figure it out. My understanding is that nothing comes from nothing. For something to exist, there must be material or a component available, and for them to be available, there must be something else available. Where did the material come from that created the Big Bang, and what happened in the first instance to create that material? – Peter, 80, Australia. "The last star will slowly cool and fade away. With its passing, the Universe will become once more a void, without light or life or meaning." So warned the physicist Brian Cox in the recent BBC series Universe . The fading of that last star will only be the beginning of an infinitely long, dark epoch. All matter will eventually be consumed by monstrous black holes, which in their turn will evaporate away into the dimmest glimme
Why Do Stars Twinkle? When a ray of light travels from one medium to another it ‘bends’. This phenomenon is referred to as refraction . If it travels from a rare medium to a dense medium, it bends towards the normal and if it travels from a dense medium to a rarer medium, it bends away from the normal. The speed at which the light travels changes depending on the medium and therefore this bending occurs. This effect can be observed when light passes through a prism or a glass slab and even when light passes through water. The light ray travels from air to a medium of different densities here. So how are refraction and twinkling connected? The atmosphere Of Earth is made of different layers. It is affected by winds, varying temperatures, and different densities as well. When light from a distant source (a star) passes through our turbulent (moving air) atmosphere, it undergoes refraction many times. When we finally perceive this light from a star, it appears to be twinkling! This is