Question

the infinite space having millions of galaxies

Answer 1

universe is the infinite space having millions of galaxies

Answer 2

Space is not a finite object that fits into our head. Space researches have claimed that there are nearly 200 trillion galaxies in the known universe as per the calculations and photos from Hubble Space Telescope. Universe is extending in all direction every second and so our observation on it.  

Hubble telescope and Deep space research made the calculation possible with tons of data that were collected from the past 10 years.