I dont believe tht there is any importance of number 7 or any other number in general or in Islam specially.... yah Number 7 is quite common and many people believe it as lucky number. it just superstitious...

in Islam Action is important and "intention" (Nee'yat) is the most important factor of success or failure of any act instead of number of time the act is taken. Every number is important in Islam such as ..

No. 0 as there is no God but Allah
No. 1 as Allah is "Wahid" wahad-hu-la-sharik-Allah-hu
No. 2 as 2 Farz in Fajar prayers and 2 Farz in Qasar prayers
No. 3 as 3 Farz in Maghrib and 3 witir in Isha prayers
No. 4 as 4 Farz in Zohar, Asar and Isha prayers
No. 5 as 5 prayers in a day and five pilers of Islam
No. 6 as 6 pilers of faith (Iman)
No. 7 as u said but sorry i cant found any importance of No. 7 in Islam it may be ritual to use 7 as lucky or else.

My questions: is there any scientific proof that there are 7 Aaasmaans and 7 Zamins or this mentioned in Quran?
Any one plz answer me with reference… Thanks