The Bible tell us that, after his death and resurrection, Jesus appeared to his disciples and many others with 'convincing proofs' that he was alive, and then went on to give them final instructions before he returned to heaven. This event is recalled by the Christian Festival of 'Ascension', which is celebrated 40 days after Easter Sunday, so always take place on a Thursday.
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At the time when the Bible was written, people still didn't know that the world was a ball in the vastness of space, neither could they fly, so they still had the idea that the earth was flat and rested on Hades
(Hell) that was beneath the earth, so Hades was therefore a bottomless pit, with heaven as the 'home of God' above the sky, as humans couldn't reach it. It's not surprising, therefore, that Jesus' return to God in heaven was seen at that time as 'Ascending' back to heaven.
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All the Bible accounts tell us that Jesus rose alive from the dead after crucifixion and was seen by the women at the tomb, but differ slightly on what happened next. None of them say explicitly how Jesus returned to heaven, but use words that imply rising. In their Gospel accounts, Matthew and John don't mention it at all, Mark and Luke just say 'taken up into heaven'
(Mark 16:19, Luke 24:51).