The concept is that when The Rapture happens, all the World will see (if they notice anything at all) is a bunch of people disappearing. The Pre-Tirb Rapture based fiction usually never has them even being able to put the pieces together that they all followed the same Faith.
The basis comes from only one of the classic Rapture passages. 1 Corinthians 15:52.
In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.The idiom is of speed not visibility. But the point is that the phrase essentially means "blink and you'll miss it".
This passage lacks most aspects of what happens at The Rapture. Including what the word "Rapture" itself refers to, us being Caught Up/Gathered. Nor does it have the Parusia, Jesus coming on The Clouds.
It's only about three things. 1. The Last Trump, 2. The Resurrection of believers, 3, The still living Saved being change/perfected into our Resurrected states without dieing first.
That is all that is happening at that speed. Once that happens, then Jesus comes to Gather us, and elsewhere The Bible is always clear The World sees that. In Matthew 24, I Thessalonians 4, and Revelation 14.
Chuck Missler and Mark Easton have done a lot of material about Dimensions and the Science of The Resurrection. About how Jesus in the Resurrection was in more then just our four dimensions. And I recommenced their work on that even though I'm more strictly Young Earth Creationist then they are.
But Missler makes a statement that I'm sure he has this Secret Rapture idea in mind with. Where he says Jesus was only "Seen by loving eyes and touched by loving hands". By which I'm sure he means only Saved individuals.
My problem with that is this flies in the face of the efforts of all these other Christians seeking to show how Historically proven the Resurrection is. If 100% of the eye witnesses were people who already supported Jesus. Paul spoke in his Epistles of there being many, many witnesses to the Resurrection.
1 Corinthians 15:3-8
For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; And that he was buried, and that he rose again the third day according to the scriptures: And that he was seen of Cephas, then of the twelve: After that, he was seen of above five hundred brethren at once; of whom the greater part remain unto this present, but some are fallen asleep. After that, he was seen of James; then of all the apostles. And last of all he was seen of me also, as of one born out of due time.Besides simply the large number, I notice the inclusion of The Lord's half-brother James. His siblings were not believers yet at any time they appear during his ministry. The typical conclusion from this verse is that James became a believer after seeing the Risen Jesus. And we certainly know Paul wasn't saved yet when he saw him.