$A$ total solar eclipse is observed from the Earth. At the same time,an observer on the Moon views the Earth. She is most likely to see ($E$ denotes the Earth):

Which of the following is the coldest planet?

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

Assuming that the dimmest visible star to the naked eye has a magnitude of about $6$. The brightness of planet Venus (magnitude = $-4$) with respect to this star is ........ times brighter.

$A$ group of bright and faint stars is called

The farthest objects in our Universe discovered by modern astronomers are so distant that light emitted by them takes billions of years to reach the Earth. These objects (known as quasars) have many puzzling features,which have not yet been satisfactorily explained. What is the distance in $km$ of a quasar from which light takes $3.0$ billion years to reach us?