The-big-bang

The big bang

     About 14 years ago, the universe materialized out of unknown reasons. Infinitely smaller than an atom to begin with, the universe expanded to a trillion kms across  in under a second-an event called the big bangTime cameb into existence when the universr begen, so the questions ‘’what happened before?’’ has no meaning. Space also came into existence. The big bang was not an explosion of matter through space- it was an expansion of space itself.At first the universe consisted of pure energy , but within a trillionth of a second some of this energy turned into matter, forming a vast soup of subatomic particles(particles smallerthan atoms). It took nearly 400,000 years for the particles to cool down  enough to form atoms, and then another 300 millon years before the atoms formed planets stars, and galaxies. The expansion that began in the big bang continues to this day, and most scientists think it will carry on forever.

 The expanding universe

     The illustration below does not show the shape of theb universe, which is unknown. Instead, it is timeline that  shows  how the universe  has expanded  and changed  since the big bang we know the universe is expanding because the most distance galaxies are rushing apart at fantastic speeds. By running the clock backward, astronomers figured out that the expansion began 13.8 billion years ago at a single point: the big bang.

Discovery of the big bang

     The first scientific evidence for the big bang was found in 1929, when astronomers discovered that light from  distant galaxies is reddened. This color change  happens when  objects are moved away  from us, the more distant the galaxies are, the faster they  are rushing  away. This shows that the whole universe is expanding.

Big bang afterglows

      More evidence of the big bang came in  the 1960s, when  astronomers detected faint  microwave radiation coming from every point in the sky. This mysterious energy is the faded remains of the instance burst of  energy released in the big bang.

Changing elements

     For hundreds of  millions of years, the universe consisted almost entirely- the very hydrogen simplest chemical elements.  After  stars  appeared, new elements began  to be made in the cores of  dying stars. All the complex in our bodies  were  forgot in dying  stars this  way.

Big  bounce theory

    What  caused  the big bang? We may never  know for  sure, but   some scientists have suggested that  there may have been  lots  of big bang .ex: universe expands , big bang , universe shrinks.