Conjunctions | Universe Today

Written by Jerry Coffey

The exact definition of astronomical conjunctions is: when,as seen from some place (usually the Earth), two celestial bodies appear near one another in the sky. There are many types of conjunctions. They are broken down by how the conjunction appears: ecliptical longitude, in right ascension, and ecliptical latitude. All of these terms are defined in other articles here on Universe Today. I want to tell you about a few notable past conjunctions and then let you know about several that are going to happen throughout 2010.

The most famous of the conjunctions is probably the sighting of the Christmas Star of biblical fame. Scientist were able to prove the biblical reference with sound research. Using information garnered from the book of Matthew and the generally accepted consensus that Christ was born between 3 BC and 1 AD, researchers found that historical records and modern-day computer simulations indicate a rare series of planetary groupings(conjunctions) during the years 3 BC and 2 BC. On 12 August, 3 BC, Jupiter and Venus appeared very close together in the dark hours just before sunrise, appearing as bright morning 'stars.' They would have been visible in the eastern pre-dawn sky. A short ten months later, on 17 June 2 BC, Venus and Jupiter conjoined again. This time the two planets were so close that, without the use of modern optical aids, they would have looked like one single, brilliant star that could easily be seen with the unaided eye throughout the Middle East.

One of the most recent conjunctions occurred on December 1, 2008, Venus, Jupiter, and the crescent moon converged in a rare grouping to form a tight triangle in the evening sky after sunset, visible worldwide. It looked like a happy V face, or a frowning face depending on your position on Earth. In late April 2002, a rare grand conjunction occurred. Saturn, Venus, Mercury, Jupiter, and Mars were all visible concomitantly in the west-northwest sky, shortly after sundown. This will not happen again until July 2060. On that occasion the quintet will be bunched in the east-northeast sky, shortly before dawn.

2010 will see a total of eighteen conjunctions throughout the year with as many as three occurring in some months. None of them will be on the scale of a grand conjunction, but will be cool to check out, anyway. Here is a link to a chart that shows all of the conjunctions that will happen in 2010. Here on Universe Today we have a great article and images about the triple conjunction from December 1, 2008. Astronomy Cast offers a good episode about the research related to the Christmas Star being a conjunction.

Filed under: Astronomy