Venus looks brighter than other planets because

Which one of the following is known as $Saptarishi$?

$A$ particular emission line,detected in the light from a galaxy,has a wavelength $\lambda' = 1.1\lambda$,where $\lambda$ is the proper wavelength of the line. The distance of the galaxy from us is:

What is the ratio of the maximum mass of the observable universe to the minimum mass of an electron?

$A$ group of bright and faint stars is called

The tail of the comet is due to