Earthlings Dazzled by Venus-Jupiter Close Encounter
The two brightest planets in the sky, Venus and Jupiter, will likely draw attention to the western sky as darkness falls this week.
Planetariums, observatories and perhaps even weather forecast offices might get a number of inquiries about what those "two bright lights in the sky" are.
On Monday evening they'll appear to line up side-by-side, and on Tuesday evening, they will be separated by just 3 degrees (about the width of two fingers held out at arm's length), with Venus standing just above and to Jupiter's right.
Shining in a completely dark sky for more than two hours before finally disappearing beyond the west-southwest horizon after 10:30 p.m. local daylight time, this planetary pair may appear even more eerie when they're sitting just above the horizon as opposed to when they appear higher in the sky.
There are also three interesting aspects concerning this eye-catching configuration.
Eight Times Brighter
When the planets are closest, Venus will glow at magnitude -4.3, while Jupiter will shine at -2.1 on astronomers' magnitude scale in which lower numbers correspond to brighter objects (negative numbers suggest an extremely bright view).
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So how much brighter than Jupiter will Venus look? You might think that Venus is 2.2 times brighter than Jupiter, but this would be wrong. Here's why:
During the second century B.C., the Greek astronomer Hipparchus placed the naked-eye stars into six brightness categories. We still use his methodology today: The lower the figure of magnitude, the brighter the object.
Then in 1856, British astronomer Norman Pogson defined Hipparchus's magnitude scale mathematically, making it follow a logarithmic relationship, in which two objects that differ in brightness by five magnitudes differ in apparent brightness by a factor of exactly 100. In other words, an increase of one magnitude represents a brightness increase that is equal to 2.512.