Southern California: Home of the Stars

Although I conceived this as a blog about information, about as broad a topic as I could come up with that didn’t involve actual research on my part, I can’t resist devoting a brief entry to astronomy, in particular the spectacular show that Venus has been putting on in the night sky lately. This is a photo I took last night (Monday, March 26, 2012) from my front yard in Los Angeles, about two miles east of the Pacific Ocean. The view is to the west. Those two objects glowing between the palm trees are the moon and the planet Venus. (I’ll ┬áleave it to the reader to figure out which is which.) Here they are:

Moon and venus with palm trees

The moon and Venus in conjunction over Los Angeles.

Honestly, I think this is about the most beautiful conjunction of the moon and Venus I’ve ever seen, though the palm trees certainly help make it more dramatic (or at least exotic). If the photo had been taken slightly later in the evening and the sky had been a bit darker, Jupiter might have been visible too, because the largest planet has also recently been in conjunction with Venus. Those two were more dramatically in conjunction two weeks ago and I wish I’d had the sense to take a photo of that conjunction between these same two palm trees, just for comparison purposes. Needless to say, it was a gorgeous sight to see.

For those of you who aren’t much into astronomy (which seems to include a large percentage of the human race), let me explain the significance of the photo. Certain bodies in the sky, primarily the planets that are visible to the naked eye (Venus, Mars, Jupiter and Saturn) along with the moon and the sun, move in a pattern that is not fixed relative to the background stars. That’s because they’re spinning in an intricate ballet in the inner portion of the solar system that includes our own planet, the earth. The stars, meanwhile, are almost unimaginably distant and, while they do move relative to one another, they do it so slowly from our point of view that they might as well be a fixed backdrop to the planet dance. The result is that the relatively nearby planetary objects are constantly repositioning themselves relative to the background stars and these positions change from night to night. Usually this isn’t all that interesting unless you’re the type of person who, like me, grew up owning telescopes, but occasionally these celestial objects find themselves forming interesting juxtapositions. A particularly close juxtaposition is called a conjunction. Conjunctions happen fairly frequently because the moon, sun and planets all move through a narrow path in the sky called the ecliptic, which represents the plane of our solar system, and that gives them lots of opportunities to snuggle up close together, as the moon and Venus are doing above.

The three brightest natural objects in the sky are the sun, the moon and Venus, in that order. We’re used to seeing those first two. The sun is so bright that we never really see it in conjunction with anything, because everything else is lost in its glare (though if the moon actually passes in front of it we get an eclipse). The moon, on the other hand, can appear in conjunction with all of the other visible planets and the most spectacular conjunction is with Venus, a planet that is so bright in the sky that you’re likely to mistake it for an incoming airplane until you notice that it isn’t moving. Conjunctions between Venus and other planets, including the moon, are relatively rare, because Venus is an inferior planet. No, this doesn’t mean it made bad grades in school, but refers to the fact that, unlike most of the other planets, it’s closer to the sun than the earth is. Thus, we never see it all that far from the sun and only get to see it in the evening after the sun sets or in the morning before the sun rises — never in the middle of the night. Usually it’s so close to the sun that it’s hard to see and not very interesting, but right now it’s swung to one of the far extremes of its orbit as seen from earth and it’s staying up for several hours after sunset, way past its normal curfew. This allows for spectacular conjunctions like the one above with the moon and the recent one with Jupiter.

If you look at the sky tonight from your own yard, you won’t see the image in the photograph above, with or without the palm trees. The moon moves fast, making an entire orbit around the earth in about 28 days, and by tonight it will be considerably more distant from Venus than in the picture, though you’ll still see both objects in the same portion of the sky. In fact, you might want to check the sky for the next several nights, trying to spot the moon, Venus and Jupiter in the few hours after sunset before they become quite distant from one another again. (Jupiter will stay relatively close to Venus longer than the moon will. The moon is one of those type-A stellar bodies — always in a hurry to be someplace else.)

And may I wish you clear skies, like the ones we get in the evening down here near the Pacific. Every now and then Los Angeles really is the home of the stars.