In our solar system,there is one sun and

The number of stars in our solar system is

According to Hubble's law,the redshift $(Z)$ of a receding galaxy and its distance $r$ from Earth are related as

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

What were the thoughts of the ancient Indian sage and scientist Aryabhatta regarding planetary motion?

$A$ group of bright and faint stars is called