light ...

... how light is light ? ... why does light become very big and heavy such as a 1000 year old tree ...

philosophers of science point out that science doesn't answer why questions, it only answers how questions. Science doesn't explain ... science describes.

my explaination would prefer to choose the experience of a photographer, consider the picture posted in "trans time", the image consists of both stationary objects such as the tree bark, the insects in a meeting and the busily moving insects. now you can imagine me using a flashlight (1/10,000 of a second) to arrest all movement or use 1/2 second exposure using available light. so the point being, the stationary items dont have time influence them and the moving subjects influence light. so ones perception and camera setting is the crucial factor in understanding light.

it is said that, If you can't explain something to a six year old, you don't really understand it !

p.s : every atom in the universe is physically bound to all others via two anti-parallel threads twined around each other like strands of DNA !!