Expert: James Gort - 5/2/2008

Question
i have heard that sky is dark because universe is young.that's why light from distant star has not yet reached our planet.if this is the reason for sky is dark then the night sky should grew brighter and brighter day by day......

Answer
Hi Vineesh,

While it is true that some stars are forming at distances such that their light has not yet reached earth, others stars are dying and dead, and their light is still coming to earth.  That said, you are correct.  More distant stars are forming than dying, and the night sky is growing brighter.  But it will take millenia to notice a change!

The "young universe" seems to be the accepted answer, with the apparent red-shift of galaxies contributing only very little to the effect.

Cheers,

Prof. James Gort