knowledge

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 app...

Why Is The Mona Lisa So Famous? The  Mona Lisa  is a painting that needs no introduction. Painted during the Italian Renaissance by Leonardo da Vinci, the  Mona Lisa  is widely considered to be the most written and talked about portrait of all time. Every year, the painting draws flocks of museum goers to the Louvre to witness the elusive expression of the painting’s female sitter that they’ve seen captured in movies or plastered on everything from coffee mugs to fridge magnets. Why is the Mona Lisa so famous?  The Mona Lisa is famous because it is widely praised as evidence of the Leonardo Da Vinci’s mastery of human anatomy and natural realism. The  Mona Lisa  is also famous because of its exhibition at the Louvre, as well as its widespread reproduction in popular art and culture. The Mona Lisa   hundreds of millions of dollars, making it one of the most valuable pieces of art in the world. But why is the Mona Lisa...

The sky appears blue during the day due to a phenomenon called Rayleigh scattering. When sunlight enters Earth's atmosphere, it encounters particles such as oxygen and nitrogen molecules, which are much smaller than the wavelength of visible light. The light interacts with these particles, causing it to scatter in all directions. Blue light has a shorter wavelength than other colors of light, which means it is scattered more easily by the particles in the atmosphere. This is why the sky appears blue to us when we look up during the day. Here is an image that shows how the scattering of light causes the sky to appear blue: As you can see in the image, the blue light is scattered in all directions, while the other colors of light are scattered in different directions or not at all. This results in a blue color dominating the sky during the day. It's worth noting that the sky can appear different colors at different times of day, such as orange or pink during sunrise or sunset. Th...