Night Sky: String of planets

It won’t last long. But now and for the next couple of weeks, a gorgeous row of bright planets, like a string of pearls, grace the low southwestern sky from 5 to 6 p.m. each night.

The brightest, lowest and right-most is Venus. Wow, it is gorgeous. It’s been an evening star nearly all year long, but is now at its brightest. Look far to its upper right to the second brightest “star” and that’s Jupiter. Halfway between them is much dimmer Saturn.

If you have any kind of backyard telescope, Saturn will show off its amazing rings, Jupiter will display one or more dark bands near its equator, as well as its four bright Galilean Moons. And Venus? Well, telescopes increasingly show a thinning but ever-larger crescent shape, which is the best Venus can ever offer.

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On Friday evening, December10 and Saturday the 11th, the Moon will hover on that same line, to the left of the planets. This line shows you the plane of the solar system, the flat, pancake-like shape upon which all the planet orbits, along with the Moon’s, are located.

This is worth another two minutes of your attention. You see, we normally use the horizon as our reference point. And while the horizon is always horizontal by definition, it’s in a different place depending on where you live. But that string of planets and the Moon? Well, that’s inviolable. Never-changing. The solar system’s flatness never alters its orientation in space.

One changes, the other doesn’t. Result? Well, if you visit the tropics the next few weeks, you’ll see that string of planets forming a vertical line upward from your horizon. But if you were in polar regions, the planet line would appear almost horizontal, barely angled above your horizon. So your earthly horizon changes, but that distant solar system plane, also called the ecliptic or the zodiac, holds its position. The angle it makes with OUR horizon tells us we are neither near the equator nor near the poles, but about halfway between the two.

Adopting that line, that plane as a new reference point bestows a new sense of distance and largeness and grandeur. It’s a good thing. And it’s right there the next clear evening.