that's amazing!!!

      BLACK HOLES

   massive stars, ten to a hundred times bigger than our Sun,have a life story different from the one illustrated here.
   they eventually explode,creating a supernova. all the matter from which they are made may collapse back on itself under gravity.not even light can escape from the collapsing star.it becomes a 'black hole' invisible to even the most powerful telescope. 









WHY IS THE SUN YELLOW?
 
       the colour of a star depends on how hot it is- and this, in turn , depends on its size and age. our sun is a star of medium size and brightness, with a surface temperature of about 5500 C (10000 F), which makes it look yellow. as it gets older and uses up more of its energy, the surface temperature will drop to about 4000 C (7200 F) and it will look red. when it has exhausted almost all of its energy, the sun will collapse and heat up briefly in a white flare.



WHAT MAKES THE SUN SHINE?

       light from the sun radiates through the entire solar system. this light is generated in the core of the sun, where temperatures reach around 15 million C (27 million F), as hydrogen gas is converted into another gas , called helium, in a series of thermonuclear explosions, billions of times more powerful than the biggest nuclear bombs: a mere  pinhead of these gases would be hot enough to ignite everything for 100 km (60 miles) around. the hot gases churn slowly towards the sun's surface, where the burning solar gas shines for millions of miles into space.


WILL THE SUN LAST FOREVER??

    stars last a long time, but not forever. our sun probably reached its peak brightness about 800 million years ago,and should continue to glow with the same intensity for another 1.5 billion years before beginning to fade. its decline will be a slow process. firts, in about 4 billion years, it will grow into a huge red giant star, swallowing the earth and the inner planets. then it will collapse into a white dwarf star before cooling and becoming extinct.

WHY DOES THE SKY CHANGE COLOUR?

Light rays from the sun are made up of violet,inaigo,blue,green,yellow,orange and red rays. When these rays pass though he atmosphere, they are scattered in a different directions.During daytimes, water droplets and gas molecules scatter blue light rays, making the sky look blue. In the evening ,the atmosphere can be full of dust particles.these scatter the red light rays,creating red sunsets.