Secretofphysics

The universe is the whole of existence ,all of space , matter , energy and time . The universe is so vast as to be unimaginable , but we do know that it is steadily  expanding following its beginning 13.8 million years ago in an explosive event called big bang .  people used to think of the universe as a giant sphere , but we know that things are not simple . the universe probably has no centre or outer edge . only a fraction of it  the observable universe is visible to us the whole universe may be vastly bigger than this .  The three dimensions of space are " bent " by the force of gravity from matter  in the universe into four dimension that we can't see. this is hard to visualize , so scientists use the metaphor of a  two dimensional rubber sheet to explain the idea . the mass of the universe could bend this rubber sheet in one of three ways , depending on how densely packed with matter the universe is most scientists now think the shape of the universe ...

  The big bang theory is a physics theory which explains the origin of universe . The big bang theory states that the universe began as a hot and infinitely dense point , only a few millimeters wide , it was similar  toa supercharged black hole .About 13.7 billion years ago this tiny violently exploded. And it is from this explosion , the big bang that all matter ,energy, space and time  were created  .The next two stages was  called radiation era and matter era ,which shapes the universe . radiation era named dominance of radiation after big bang . this era is made of smaller stages call epochs occurs in first ten thousands years. the earliest is planck  epoch no matter existed  in this time only energy and ancestor four force  of  nature , at the end of this event a super force  left away the gravity. the inflationary epoch begin in which the universe rapidly expand  . this time universe is pipeing hot and it churned with electron...

     THE SUN:                                                                                     The sun is the star at the center of our solar system. It is heated by nuclear fusion( two nucleus collide two masses of the nuclei tends to form single nuclei which is less in mass then other two masses the remaining mass expressed as energy it is called as nuclear fusion). Sun express this radiation in the form of light ,ultraviolet and infrared. The sun's radius is 695,000 kilometers. the sun contains 73% of hydrogen 25% of helium, small amount of oxygen and carbon ,neon and iron. It is formed    about 4.6 billion years ago ,formed by gravitational collapse of matter which is in molecular cloud . Most of the matter gathered in center , other to orbitin...

Black hole :                                                                                      Black hole is an massive object in the universe. where force of gravity is very strong not even a light or electromagnetic waves cannot escape from it. The boundary of black hole is called as event horizon, which is truly cannot see  . when something crosses the event horizon it collapses into the black hole 's singularity which is the mid point of black hole . In there space time and laws of physics cannot apply. scientists theorized several types of black holes are stellar , super massive ,intermediate, miniature. stellar black holes are formed when massive stars die and collapse . The are roughly 10 to 20 times the mass of our sun. There can be millions of stellar black h...

  Dark matter:                                                                                                                   In the early 1990s, everyone thought that expansion of universe is might slowing due to gravity. It is not Theoretically proved but the universe is full of matter and the attractive forces of gravity pulls all matter together. Later 1998,the Hubble Space Telescope came with observation of very distant supernova that showed that , a long time ago the universe was actually expanding slowly than it is today.                                                 ...

  Gravity and General theory of relativity:                                                         Gravity:                                                                 what is gravity? It is an illusion extract by two objects with non-zero mass. Not only, gravity means the Apple  falls on the earth. You may consider two objects in the space an astronaut and an apple, in this case both two objects pulling other object towards each other. The astronaut pulling the Apple towards him and the Apple pulling the astronaut towards it. This attractive force between any two  masses is called the gravitational force . Gravitational force is an attractive force between any t...