I'm not particularly interested in believing in Aliens, but I do believe the devil still is up to his old tricks and there is nothing wrong with speculating upon what history shows us along with the Bible which gives us good hints even though not all the info on the Nephilim. Now the link to read a little about this topic I will post, but you should read for yourself before scoffing too much. Something is obviously happening to make people believe they are abducted by UFOs and even the astronauts have given specific testimony about UFO encounters.
"Sons of God", translated from the Hebrew, always means "angels". Check out Job 1:6; 2:1, and 38:7. The New Testament - Luke 20:36, according to Chuck Misslar. Luke 20:36 says that angels cannot be given to marriage, but that is when they are in their natural state - not the fallen state of the angels that followed satan in the rebellion described in Revelations.
Revelations 12:4 And his tail drew the third part of the stars of heaven, and did cast them to the earth: and the dragon stood before the woman which was ready to be delivered, for to devour her child as soon as it was born.
5 And she brought forth a man child, who was to rule all nations with a rod of iron: and her child was caught up unto God, and to his throne.
7 And there was war in heaven: Michael and his angels fought against the dragon; and the dragon fought and his angels,
8 And prevailed not; neither was their place found any more in heaven.
9 And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.
The superhuman offspring between these angels, the Nephilim, who according to Enoch, quoted by Jude, now wait in chains (Jude 1:6) for judgment. See 2Peter 2:4, also.
Nephilim - "the fallen ones"; also HaiGibborim - "the mighty ones", as Genesis says they were mighty among men like giants physically and renown in deeds of strength. History considers many of these varied accounts as merely myth, occuping the same time frames, in many cases, as those accounts in the Bible. Greek mythology and the Bible speak of men over 10 foot tall. Also, who built these ancient monuments we see scattered around the world with such astromomical precision? I don't think the Bible wants us to major on these things, but leaves it to us to have faith that God is in control, and we should at least be able to give an answer that does not narrow out the power of such beings desribed in the Bible. The Bible says that the lasts days will see a people full of religion but denying the power of God and His word. The devil is to be respected as a powerful being able to deceive the whole world, and even the angels would not bring charge against him, asking that God Himself rebuke his works. We are to be aware of HIs power to deceive and warn against such a great adversary who seeks to devour and destroy God's creation in mankind. (Revelation 16:14; Eph. 6:12; 1Pet. 5:8; 2Pet.2:11; Jude1:9)
Rephaim, Emim, Horim, Zamsummim in Gen. 14,15; Arba, Anak & his seven sons (Anakim) encountered in Canaan (Numbers 13:33); Og King of Bashan (Duet.3:11; Josh.12 ) Goliath and his 4 brothers.
Here's some of the info at Chuck's site:
http://www.khouse.org/topical_bible_study/nephilim/