Asalamu Alaykum,
Allah has revealed the Quran to the Prophet Muhammad
to teach people about their purpose of existance.
Allah (SWT) says in the Quran, 51: 56-58:
And I (Allâh) created not the jinns and humans except they should worship Me (Alone).
I seek not any provision from them (i.e. provision for themselves or for My creatures) nor do I ask that they should feed Me (i.e. feed themselves or My creatures).
Verily, Allâh is the All-Provider, Owner of Power, the Most Strong.
We need to remember the Quran is not revealed to tell people about every single aspect of the universe, nor is its purpose to provide a complete medical journal etc.
Rather, we should be concerned with Tawheed. This is the message that all the Prophets were given. From Adam through to our beloved Messenger Muhammad
. So we develop our knowledge of Islam according to the Quran and the sunnah.
Even if there is life on other planets, this does not mean anything, except that Allah created it. Allah is the creator of all that exists.
With regards UFO sightings, Alien Abductions and so forth. The unexplainable things of the Supernatural are easily explained in Islam.
Firstly, the people may be imagining it, due to hallucination or their mind playing tricks.
Secondly, they could be seeing Jinn. As we know Allah created the Jinn as well. There are good jinn as well as evil Jinn who serve their Master Iblis (the devil).
There are Muslim and non-Muslim Jinn just as with humans. However, Jinn have order not to interfere with Humans. Those who are evil amongst them are allied with the Shaytaan Iblis, the latter is the king of the Jinn. The evil jinn's job is to make people disbelieve in Allah. Their job is to make people do Shirk (associate partners with Allah / Disbelieve in Allah). They do this in numerous ways: such as MAgic, soothesayers.. building supersticions by making people believe in Ghosts, aliens, ufo, or by getting people to do things which are seen as amazing etc.
The Jinn can transform themselves into various shapes and appear as different people (They can never appear in proper appearance of any of the Prophets)
One must distinguish between magicians and tricksters. The latter do not use "Magic", but still not good because they fool people.
Magic is something that is kept in the scrolls that some Jews know about. Their Rabbis had the books passed down from the time of Soloman that taught Magic and summoning of the Jinn. It is haram to do that, and those were cursed people who were not believers of Allah. Basically, they sold their soul to the Devil. Today, most of the magicians are Jewish, Paul Daniels, Uri Geller, David Copperfield.
I remember seeing interviews with Uri Geller, Jewish Magician. He retold a story of when he started magic. He said that he was in Israel and was a soldier. He went into a graveyard and suddenly felt a power around him. He spoke to that power and agreed to work with it! And since that day he does magic! -- If you study the Quran and Hadith, then you will know that Magic is done when the Jinn make people do Shirk. It is the Jinns doing. Other then that, there is nothing special about it or their power is not greater than that of Allah. Never. Rather, the magic is the doing of the Shaytan as it is part of his natural ability to do things that for humans is impossible. i.e. travel great distances at very fast speeds, make things disappear or bend objects etc.
