There is a nearly three century old prophecy by Isaac Newton about the second coming of Christ. I call it a "prophecy" because it's a prediction of the future, and I call it "his" prophecy because the prophecy is extra biblical. It's based around a theory and observation made by Newton about what was then an as yet future period of time when Jesus would return to the earth. In other words, this is a veiled attempt to predict the rapture or the second coming, one or the other. The premise is built around a seeming discrepancy in the prophecy of Daniel 9 that speaks of a period of 7 weeks, plus 62 weeks of years (a week of years was a biblical idiom for a period of 7 years) from the declaration of the rebuilding of Jerusalem to the return of Jesus Christ for the church.
Newton's assumption was that this odd 7 week block (49 years) of time was separate from the 62 years later spoken of in the prophecy and thus had post death implications for Jesus. IE, the rapture or His second coming. There are actually numerous variations on this prophecy, but the most common centers around the idea that 49 years to the day after Jerusalem was recaptured this prophecy was to unfold. That day came and went on Sept 23rd, 2015 and nothing happened. This is counting forward from June 7, 1967 to Sept 23rd, 2015.
Now the proponents are backpedaling and saying that the timeframe is in 365 day years pushing its fulfillment now back to November at some point. However, time and again this prophecy has been disproved, and its adherents have simply shifted the date forward to fit with their next available window. The date prior to 1967 was 1948 + 49 years, of which obviously nothing happened. There's also further problems with his prophecy that I will not go into right now. But basically he is taking an apparent discrepancy in the bible and building doctrine on it.
The disparity comes from Daniel 9:25-26a which reads "Know and understand this: From the time the word goes out to restore and rebuild Jerusalem until the Anointed One, the ruler, comes, there will be seven ‘sevens,’ and sixty-two ‘sevens.’ It will be rebuilt with streets and a trench, but in times of trouble. After the sixty-two ‘sevens,’ the Anointed One will be put to death and will have nothing.[g] The people of the ruler who will come will destroy the city and the sanctuary. The end will come like a flood:" Little is known why this seeming disparity exists.
However, if one were to count forward 69 weeks of years (483 years x 360 prophetical calendar days) they would come to the exact date Jesus died. Not 62, but rather 69. That's because it wasn't until the 4th decree to rebuild the city (there were four total, but it wasn't until the last one that actual permission to rebuild the city itself was given) that the countdown actually began. At that point if you go forward 360 days x 483 years you come to the exact day Christ died. That being true, then the 49 years spoken of are actually part of the 62 weeks that follows it.
Why there is a separation between the dates is unknown, and the bible does nothing to explain that. All math trying to explain it away to other things utterly fails, leaving nothing but Daniel's 70th week remaining to be fulfilled. Thus Newton's prophecy is invalid, and thus this entry is labeled as debunked as this is clearly a false prophecy. Not the prophecy in Daniel 9, as that's a valid, fulfilled prophecy as recorded by history itself, but rather I am speaking of Newton's interpretation and the personal prophecy he developed from it.
Also, there is innumerable proofs that Newton made quite a few other predictions, such as the second coming of Christ (proposed to be in the year 2000) that came and went without happening. As such, per the bible, he is officially a false prophet and may comfortably be ignored.
(*Do you have a better description, or did you find an error? Please let me know.