Peace Omara
Appearing on the moon, Sun and Hajre Aswad are not signs of Al-Mahdi. The true signs of Mahdi is this:
1) He will be given bayah but he will strongly refuse until he is forced to accept 2) He will be in the Haram of Makkah when first spotted 3) He will be crying and supplicating at the doors to the Kabah whilst bloodshed will happen in the mataf. 4) He will lead a military convoy 5) He never goes into ghaib or hiding and the whole world becomes governed by Islam before he dies.
Osama Bin Laden ?