I've heard this quite a lot...

Apparently quite a few scientists converted to Islam because they heard Islamic prayers coming from space?

Please, please save this somewhere on your computer so you can laugh at yourself when you turn 15.

I'm Muslim and I don't believe that. Some people tell lies thinking that it's all "good propaganda" but in the end those are just lies and lying is a sin. Forget about alien mosques. BUT there were a lot of cases where scientist converted to Islam after reading its holy book - Qur'an. Some recent discoveries about our planet and life on it are described in a 1400 years old book. If you're interested in that here's a good read for you:
http://harunyahya.com/en/works/998/The-Q…
http://www.miraclesofthequran.com/scient…