<p>Jupiter and Saturn will merge in the night sky Monday, appearing closer to one another than they have since Galileo's time in the 17th century.</p>.<p>Astronomers say so-called conjunctions between the two largest planets in our solar system aren't particularly rare.</p>.<p>Jupiter passes its neighbour Saturn in their respective laps around the sun every 20 years.</p>.<p>But the one coming up is especially close: Jupiter and Saturn will be just one-tenth of a degree apart from our perspective or about one-fifth the width of a full moon.</p>.<p>They should be easily visible around the world a little after sunset, weather permitting.</p>.<p>Toss in the winter solstice in the Northern Hemisphere, the longest night of the year — and the summer solstice in the Southern Hemisphere — and this just-in-time-for-Christmas spectacle promises to be one of the greatest of Great Conjunctions.</p>.<p>“What is most rare is a close conjunction that occurs in our nighttime sky," said Vanderbilt University's David Weintraub, an astronomy professor.</p>.<p>"I think it's fair to say that such an event typically may occur just once in any one person's lifetime, and I think 'once in my lifetime' is a pretty good test of whether something merits being labeled as rare or special.”</p>.<p>It will be the closest Jupiter-Saturn pairing since July 1623, when the two planets appeared a little nearer.</p>.<p>This conjunction was almost impossible to see, however, because of its closeness to the sun.</p>.<p>Considerably closer and in plain view was the March 1226 conjunction of the two planets — when Genghis Khan was conquering Asia.</p>.<p>Monday's conjunction will be the closest pairing that is visible since way back then.</p>.<p>Saturn and Jupiter have been drawing closer in the south-southwest sky for weeks. Jupiter — bigger and closer to Earth — is vastly brighter.</p>.<p>“I love watching them come closer and closer to each other and the fact that I can see it with my naked eyes from my back porch!” Virginia Tech astronomer Nahum Arav said in an email.</p>.<p>To see it, be ready shortly after sunset Monday, looking to the southwest fairly low on the horizon.</p>.<p>Saturn will be the smaller, fainter blob at Jupiter's upper right. Binoculars will be needed to separate the two planets.</p>.<p>Despite appearances, Jupiter and Saturn will actually be more than 450 million miles (730 million kilometers) apart. Earth, meanwhile, will be 550 million miles (890 million kilometers) from Jupiter.</p>.<p>A telescope will not only capture Jupiter and Saturn in the same field of view, but even some of their brightest moons.</p>.<p>Their next super-close pairing: March 15, 2080.</p>
<p>Jupiter and Saturn will merge in the night sky Monday, appearing closer to one another than they have since Galileo's time in the 17th century.</p>.<p>Astronomers say so-called conjunctions between the two largest planets in our solar system aren't particularly rare.</p>.<p>Jupiter passes its neighbour Saturn in their respective laps around the sun every 20 years.</p>.<p>But the one coming up is especially close: Jupiter and Saturn will be just one-tenth of a degree apart from our perspective or about one-fifth the width of a full moon.</p>.<p>They should be easily visible around the world a little after sunset, weather permitting.</p>.<p>Toss in the winter solstice in the Northern Hemisphere, the longest night of the year — and the summer solstice in the Southern Hemisphere — and this just-in-time-for-Christmas spectacle promises to be one of the greatest of Great Conjunctions.</p>.<p>“What is most rare is a close conjunction that occurs in our nighttime sky," said Vanderbilt University's David Weintraub, an astronomy professor.</p>.<p>"I think it's fair to say that such an event typically may occur just once in any one person's lifetime, and I think 'once in my lifetime' is a pretty good test of whether something merits being labeled as rare or special.”</p>.<p>It will be the closest Jupiter-Saturn pairing since July 1623, when the two planets appeared a little nearer.</p>.<p>This conjunction was almost impossible to see, however, because of its closeness to the sun.</p>.<p>Considerably closer and in plain view was the March 1226 conjunction of the two planets — when Genghis Khan was conquering Asia.</p>.<p>Monday's conjunction will be the closest pairing that is visible since way back then.</p>.<p>Saturn and Jupiter have been drawing closer in the south-southwest sky for weeks. Jupiter — bigger and closer to Earth — is vastly brighter.</p>.<p>“I love watching them come closer and closer to each other and the fact that I can see it with my naked eyes from my back porch!” Virginia Tech astronomer Nahum Arav said in an email.</p>.<p>To see it, be ready shortly after sunset Monday, looking to the southwest fairly low on the horizon.</p>.<p>Saturn will be the smaller, fainter blob at Jupiter's upper right. Binoculars will be needed to separate the two planets.</p>.<p>Despite appearances, Jupiter and Saturn will actually be more than 450 million miles (730 million kilometers) apart. Earth, meanwhile, will be 550 million miles (890 million kilometers) from Jupiter.</p>.<p>A telescope will not only capture Jupiter and Saturn in the same field of view, but even some of their brightest moons.</p>.<p>Their next super-close pairing: March 15, 2080.</p>