Astronomers say that on June 30, we will observe a conjunction of Jupiter and Venus in the western sky after sunset. The two brightest celestial objects after the Sun and Moon will come very close together in the night sky to form a brilliant “super star” or “double star” in the western sky, according to NASA.
The two planets, which have been moving closer to each other since the first week of June, will come very close June 27-July 4. The closest conjunction will be observed on the evening of June 30, 2015, when the two will appear to have merged into a single star.
“The main event occurs on June 30th. On that night, Venus and Jupiter will be a jaw-dropping 1/3rd of a degree apart. That’s less than the diameter of a full Moon. You’ll be able to hide the pair not just behind the palm of your outstretched hand, but behind your little pinky finger.”
While the conjunction will be visible to the unaided eye given clear skies, astronomers recommend use of a telescope or binoculars for a better view.
“Both planets will crowd into same telescopic field of view, Venus appearing as a fat crescent and round Jupiter accompanied by its four large moons. The two planets will appear nearly as the same size, but Jupiter, though much larger in reality, is much farther away… Their globes will contrast dramatically in brightness, with Venus’s crescent appearing dazzling white compared to Jupiter’s duller, striped cloud deck.”
According to Sky & Telescope contributing editor Fred Schaaf, a comparably close conjunction of Venus and Jupiter occurred was about 2,000 years ago, 3-2 B.C.
The coincidence of the date with the estimated time of the birth of Jesus Christ has caused some Christians to speculate that the June 30 conjunction could be “The Star of Bethlehem” appearing in the evening sky.
In Christian tradition, the Star of Bethlehem (Matthew 2: 1-2) was the celestial object that guided the “Magi” to Bethlehem to pay homage to Christ where he was born in a manger.
However, the speculation is rejected by some who believe that the Star of Bethlehem was more likely a comet or a supernova. Others say it was a supernatural event not explainable in scientific terms.
But many secular scholars dismiss the story as pious fiction.
According to Sky & Telescope senior editor Alan MacRobert, conjunctions of Venus and Jupiter have no effect on Earth and no influence on human affairs.
“These planetary groupings in the sky have no effect on Earth or human affairs — except for one, they can lift our attention away from our own little world into the enormous things beyond. That’s what amateur astronomers do all the time.”
Astronomer Pat Hartigan at Rice University explains that the June 30 conjunction is the best we will see for a long time. There will be another conjunction on March 1, 2023, but it would be less close.
According to Hartigan, the best time to view the conjunction is immediately after sunset, looking west-northwest. The conjunction will become more difficult to observe from two hours after sunset, according to Hartigan.
“After about two hours for most latitudes the objects will become difficult to observe as they begin to set. They are bright. You might mistake them for airplanes.”
[images: YouTube/Science@NASA; Sky & Telescope]