The Star of Bethlehem was very likely a conjunction of two or three bright planets, Jupiter, Venus, and perhaps Saturn close together at the same time. This STILL happens periodically.
"...In 1614, German astronomer Johannes Kepler determined that a series of three conjunctions of the planets Jupiter and Saturn occurred in the year 7 BC.[7] Although conjunctions were important in astrology, Kepler was not thinking in astrological terms. He argued (incorrectly) that a planetary conjunction could create a nova, which he linked to the Star of Bethlehem.[7] Modern calculations show that there was a gap of nearly a degree between the planets, so these conjunctions were not visually impressive.[34] An ancient almanac has been found in Babylon which covers the events of this period, but does not indicate that the conjunctions were of any special interest.[34][35] Dr. Karlis Kaufmanis argued that this was an astronomical event where Jupiter and Saturn were in a triple conjunction in the constellation Pisces.[36][37]
Other writers suggest that the star was a comet.[34] Halley's Comet was visible in 12 BC and another object, possibly a comet or nova, was seen by Chinese and Korean stargazers in about 5 BC.[34][38] This object was observed for over seventy days with no movement recorded.[34] Ancient writers described comets as "hanging over" specific cities, just as the Star of Bethlehem was said to have "stood over" the "place" where Jesus was (the town of Bethlehem).[39] However, this is generally thought unlikely as in ancient times comets were generally seen as bad omens.[40]
Another Star of Bethlehem candidate is Uranus, which passed close to Saturn in 9 BC and Venus in 6 BC. This is unlikely because Uranus moves very slowly and is barely visible with the naked eye.[41] ...
...In 3–2 BC, there was a series of seven conjunctions, including three between Jupiter and Regulus and a strikingly close conjunction between Jupiter and Venus near Regulus on June 17, 2 BC. "The fusion of two planets would have been a rare and awe-inspiring event", according to Roger Sinnott.[45] This event however occurred after the generally accepted date of 4 BC for the death of Herod. Since the conjunction would have been seen in the west at sunset it could not have led the magi south from Jerusalem to Bethlehem.[46] It also does not fit with an event seen at rising that might have started them on the journey.
Astronomer Michael Molnar has proposed a link between a double occultation of Jupiter by the moon in 6 BC in Aries and the Star of Bethlehem, particularly the second occultation on April 17.[47] This event was quite close to the sun and would have been difficult to observe, even with a small telescope,[48] which had not yet been invented.
Occultations of planets by the moon are quite common, but Firmicus Maternus, an astrologer to Roman Emperor Constantine, wrote that an occultation of Jupiter in Aries was a sign of the birth of a divine king.[47][49] "When the royal star of Zeus, the planet Jupiter, was in the east this was the most powerful time to confer kingships. Furthermore, the Sun was in Aries where it is exalted. And the Moon was in very close conjunction with Jupiter in Aries", Molnar wrote. [nb 5][50] ..."
http://en.wikipedia.org/wiki/Star_of_Bethlehem
http://en.wikipedia.org/wiki/Triple_conjunction