clearing concept

[robotsyntex]

hi guys

i got a question.

most of times we see the source but that light cant be used to see things. i want to know why.

for example we see star but we cant read book in that light but we can read book in sunlight. why/?

light moves in form of electromagnetic waves and their energy is not consumed.

please also give me more details related to above question

[IM Egdall]

hi guys

i got a question.

most of times we see the source but that light cant be used to see things. i want to know why.

for example we see star but we cant read book in that light but we can read book in sunlight. why/?

light moves in form of electromagnetic waves and their energy is not consumed.

please also give me more details related to above question

 

The Sun is a star.

 

The closer a star is to us, the brighter the star appears to us. In general, its brightness falls off by the square of the distance. So, for instance, a star which is twice as far away as another identical star would be four times less bright. If it was three times further away, it would be nine times less bright. Etc.

 

The Sun is so close to Earth that its light is bright enough to allow us to read a book. Other stars we see are much, much further away -- so way too dim to read a book from.

 

The Sun is about 93 million miles from the Earth. The next nearest star is Proxima Centauri, which is about 4.2 light-years (about 25 trillion miles) from Earth. If my calculations are correct, this is some 270 thousand times further away.

 

Also stars vary tremendously in their size, make-up, and brightness. So this is also a big factor in how bright the star appears to us.

Edited December 27, 2011 by IM Egdall