the universe simply existed all the time, some stars collides each other, and earth might have formed in such manner, and there was water in earth and life formed.
many millions of years ago happened all these. The universe may be or may not be complicated that does not mean somebody created these. Why not possible this complicated evolved naturally, i assume you know the mechanism of rain, one who have no idea about mechanism of rain thinks that some people are pouring water from sky, but when its mechanism is known, he can understand that there is no intelligent mind behind that.
BTW in the quran it is said that rain is happened by allah's will and allah's angel makes it rain whenever allah wishes, but no one is able to prove that, thus it is a fault in quran.
Response: But indeed, it has been proven. You see, if there is proof that Allah is the originator of the heavens and the earth and all of the universe and life itself, and also that the qur'an is the true word of Allah, then that alone proves that the rain comes by Allah's will. So the question is "What proof is it that the qur'an is the true word of Allah?" As England suggests, now the vortex beckons.
In the qur'an we read:
In ch: 4:82 of the qur'an we read, "Will they not,then, meditate upon the Qur'an? Had it been from anyone other than Allah, they would surely have found therein much discrepancy". Also in ch.2:23 we read "And if you are in doubt as to what We have sent down to Our servant, then produce a chapter like it, and call upon your helpers beside Allah, if you are truthful".
Here we have two tests to prove the authenticity and truth of the qur'an. Once applied, you will come to learn that the qur'an is in fact from Allah and has never nor will it ever be corrupted. For if you can prove that it is humanly possible to produce a chapter like the qur'an, then you are correct in saying that there is no proof that the qur'an is from Allah. But if you can not, then the question to ask is "where did the qur'an come from if it's not humanly possible to create a chapter like it?" Then you will come to learn that the originator is none other than Allahu subhanna wa ta ala. You disagree? Then the challenge still stands. Produce a chapter like it.