When Jesus returns the sky will roll up like a scroll as I recall the Bible saying. It will be an unmistakable thing. The whole earth will be moved at His presence, even the mountains. He comes in the clouds with His angels and His saints.
At this point, there will be no guesswork. His sacrifice was a one-time event, and when He returns again, it will be to rule. As I've heard said and is true.... He first came as a lamb, but He will be returning as a lion. When He returns, it will be with strength, and His Truth will no longer be trampled on - and the righteous will no longer be abused under the thumb of the unrighteous and the wicked.