Salam,

Allah (swt) revealed in the Qur'an:

"and We have sent down to you the Book explaining all things, a Guide, a Mercy, and Glad Tidings to Muslims." 16:89

I understand this as everything is covered and made clear by Islam, regarding dogma and rules. Especially what is required of us.

For example how many planets are their in the universe?, well... Allah tells us that his knowledge is infinite and we are not, when he said that if the seas where ink even then they will run out writing the words of Allah, so what we need to know is that all the stars and planets are created and will one day finish, and this is what matters. and thus this subject is covered by Islam.

and more importantly we know what we need to do about every issue as we have rules regarding everything and will be brought to account for even the smallest matter.