Salaam,
i dont beleave there are alien outside.. Like genesis say , were are under the dome, between waters , we cant leave this plane(t).
i dont beleave that the earth is a spheric bal.. i dont know what shape it has , but no spinning ball....
Allah created 3 "intelligent " creatures :
- Angels
- Djins
- Humans.
ps: some could say aliens = Djins
if Allah created aliens, then they will be same intelligents as animals.... otherwise
Iblis saying this in Quran :
He said, "My Lord! Because You misled me, surely, I will make (evil) fair-seeming to them in the earth and I will
mislead them all -
al-Hijr 15:39 mislead ==> telling to humans all happened due big bang, all life on earth has accidentally started .... bla bla bla , so humans all accidently originated at world .... so human life has no value at all....
with other words : are we getting fooled ...

but say your right....
why would you assume they are evil ?? i mean when Gog and Magog appears it will be the end of this (knowing) world. and we know when Allah tells the Angels he is gonna put "khalīfatan " on earth and the angels knew the evilness of these creatures.... and the angels wasnt talking about he other species then the "humans "??
And when your Lord said to the angels, I am going to place in the earth a khalif, they said: What! wilt Thou place in it such as shall make mischief in it and shed blood, and we celebrate Thy praise and extol Thy holiness? He said: Surely I know what you do not know.
al-Baqarah 2:30so if they come .. welcome to EARTH ...
btw if they come to earth humans will exterminate them also ....
so alien if your reading this , dont come to the EARTH or you will be doomed
PEACE