what is a light year

WHAT IS A LIGHT YEAR                                                 

IT IS THE MEASURE OF DISTANCE STARS & PLANETS ARE SO FAR THAT WE CANNOT MEASURE IN KM SO HUGE DISTANCE ARE MEASURED IN LIGHT YEARS .  LIGHT TRAVELS  299792.458 KM IN A SECOND .SO LIGHT YEAR IS THE DISTANCE TRAVELED BY  LIGHT IN ONE YEAR APPROXIMATELY 9460000000000 KM 

BLACK HOLE

BLACK HOLE                                                                                     

BLACK HOLES ARE THE REGIONS IN SPACE WITH STRONG GRAVITATIONAL FORCE. FROM IT NOTHING COULD ESCAPE NOT EVEN LIGHT . IN 1915 EINSTEIN PROPOSED THE CONCEPT OF BLACK HOLES AS A PART OF HIS GENERAL THEORY OF RELATIVITY                                                 

SOLAR SYSTEM

solar system 

 what is solar system? is it a house no it is a big place. part of milky-way galaxy with a star named by humans as sun & has a group planets which is big & small & also with several natural & man made satellite some planets has hydrogen some has other gases such as oxygen,carbon,helium etc                                                                                                  

solar system records,greatest&smallest 

1.largest planet --- Jupiter

2.smallest planet --- mercury

3.largest volcano---olymbusmons [mars]                                                    

4. rings planet --- Saturn                                                                                       

5.living planet--- earth  

6.red planet--- planet 

                                            

                                    BIG  BANG & STEADY THEORY