salam alaykum
Brother making a brief summary:
Allah only knows the keys of Ghayb.
Allah can show whatever He the Majestic, wants to show to his servants.
He subhana wa ta'ala, has showned something of the Ghayb to the prophets, because this is a sign of their prophecy.
Allah subhana wa ta'ala, has showned to people like Khidr, in surat Kahf the one who told to Musa alayhi sallam, things that Musa alayhi sallam had no knowledge about.
And concluding we are believers, Allah subhana wa ta'ala begins in surat Baqara
Alif-Lam-Mim. [These letters are one of the miracles of the Quran and none but Allah (Alone) knows their meanings]. (1) This is the Book (the Quran), whereof there is no doubt, a guidance to those who are Al-Muttaqun [the pious and righteous persons who fear Allah much (abstain from all kinds of sins and evil deeds which He has forbidden) and love Allah much (perform all kinds of good deeds which He has ordained)]. (2) Who believe in the Ghaib and perform As-Salat (Iqamat-as-Salat), and spend out of what we have provided for them [i.e. give Zakat, spend on themselves, their parents, their children, their wives, etc., and also give charity to the poor and also in Allah's Cause - Jihad, etc.]. (3) And who believe in (the Quran and the Sunnah) which has been sent down (revealed) to you (Muhammad Peace be upon him) and in [the Taurat (Torah) and the Injeel (Gospel), etc.] which were sent down before you and they believe with certainty in the Hereafter. (Resurrection, recompense of their good and bad deeds, Paradise and Hell, etc.). (4) They are on (true) guidance from their Lord, and they are the successful. (5)
Brother we believe in the ghayb, and we can not know it... we can know about it ONLY:
- What is revealed in the Qur'an and,
- What is trasmitted by authentic Hadith.
I don't know too much about it, and it is dangerous for me to enter in things that I don't have knowledge. InshaAllah, you are going to know someone who has studied better Islam, that can explain this important but delicate matter.
I advice myself and you, don't enter too much in this issues... without knowledge, we can go astray brother.
Salam alaykum