What was the Star of Bethlehem? I'm surprised this question hasn't been asked already.


  Matthew 2:1-2 (NIV)
  2&nbsp;After Jesus was born in Bethlehem in Judea, during the time of King Herod, Magi from the east came to Jerusalem 2&nbsp;and asked, “Where is the one who has been born king of the Jews? We saw his star when it rose and have come to worship him.”   
  
  9&nbsp;After they had heard the king, they went on their way, and the star they had seen when it rose went ahead of them until it stopped over the place where the child was.


This star is usually called the Star of Bethlehem, and there are many different theories as to what it was, including a supernova, a planet (such as Venus), or a comet. (An actual star is not among the options because stars don't move and then stop moving.) So, which one was it?
According to Fredrick A. Larson, this so-called 'Star of Bethlehem' is actually the planet Jupiter. He produced a video documentary called (appropriately enough) "The Star of Bethlehem" that can be found on YouTube (link) and his website. In this video documentary, Rick Larson lays out a detailed case for the Star of Bethlehem being Jupiter, which includes the following points:


These "wise men" were almost certainly astrologers.
"In the east" likely meant that the "star" rose in the east, like all stars do.
Jupiter, the King Planet, entered retrograde motion around Regulus, the King Star, crowning it.
Jupiter then coincided with Venus, resulting in the brightest star that had ever been seen.
Jupter entered retrograde motion again and appeared to stop over Bethlehem.


Larson then goes on to point out a great number of other significant astronomical events that occurred throughout Jesus' life, but they are not directly related to the Star of Bethlehem, so I won't talk about them here. The main difficulty with this is the fact that most historians place Herod's death in 4 B.C. whereas Larson's explanation depends on Herod's death being in 1 B.C. Larson does reference recent scholarship that support 1 B.C. as being the year of Herod's death.

The Wikipedia article on the subject has a section about astrological events that might be the Star of Bethlehem, and all of the suggestions in that section include Jupiter. Therefore, it's a safe bet to say that Jupiter is the most likely candidate for being the Star of Bethlehem.