Hey, hey, sky fans! Well, it wouldn’t be a day this August if there weren’t some cool nearby solar system thing going on in the skies. It’s been a little hard to keep track. It also wouldn’t be August without thick and stormy clouds keeping me from seeing anything. What’s happening now is part of a run that’s going to close out August like you wouldn’t believe. So, let’s get to it.
Remember earlier in the year, figure maybe the middle of January, when all six of the planets you can see from Earth were spilled out across the early morning sky in a long and beautiful line that stretched halfway across the sky? I say six, not five, because I’m including the one you were probably on at the time. It was great, and a great excuse to get up early, and have a bit of the morning all for yourself. When I was out having a look, it didn’t matter that I was standing out in the cold at 5:00 on a cold winter morning. The world was mine.
Well, the planets all went their separate ways for the last few months, but they’re all back and visible at the same time again. Here’s what you do. Head out tonight and over the next few nights, and look to the west, toward the sunset, maybe around a half hour or so after the sun sets. Where I live, that’s by around 8:30pm, but it might be a bit earlier where you are.
Low in the sky, you might be able to see the three planets Venus, Mercury, and Jupiter crowding together into a triangle with Venus and Jupiter separated by about the width of your first held at arm’s length. They’ll just be poking through the last of the day’s sunlight. You’ll need to look around for them a bit, but they’re there. Mercury is so close to the Sun that it always appears very close to it in our sky. It’s tough to find, even if you know exactly where to look. If you’re patient, though, you should be able to find it.
This triangle will squeeze together and then stretch out again over the next week couple of weeks or so before it starts to set too early for us to be able to be see it. Before it does, though, we’ll be able to see something that actually is truly rare, on the evening of Saturday August 27. On that evening, just as the Sun sets, Venus and Jupiter will pass each other, and will be only about a half a degree apart. That’s much less than the width of a single finger held at arm’s length! That’s incredible close! You might not even be able to see them as two different objects! This is something you’re really going to have to see to believe.
Since the planets orbit the Sun in more or less the same line, if you follow the line made by the planets in the west and turn toward the left, you’ll be brought straight over to Mars and Saturn, which are still making triangles with the bright star Antares. This means all five planets are visible in the night skies again. It’s always something when that happens.
As we’ve seen over the last few months, alignments like these aren’t that rare. The Earth and planets all circle the Sun in the pretty much the same plane, kind of like marbles a dinner plate. Well, yes, they all ellipse the Sun, but when was the last time you heard someone use “ellipse” as a verb? So, when we look out at the sky, our window on the solar system, we can see them moving back and forth in front of us along a path called the ecliptic. The ecliptic is actually the apparent path the Sun takes across the sky, but it has the handy side effect of also being more of less the line the planets take.
The planets and the Earth, along with everything else, are all moving all the time, so our point of view on them changes. It’s sort of the same thing as when you see cars driving toward you on a highway. As you drive toward them your view on them changes, and sometimes they group together and then speed apart. From here, we see our changing point of view on the planets as as them moving across the sky. Sooner or later, the planets are bound to meet up with each other from our perspective. It’s those meetings as they all move that we see as these alignments.
Alignments like the Jupiter-Mercury-Venus one are really cool because you need to look in toward the center of the Solar System, which is where the Sun, Mercury, and Venus are, and then your line of sight needs to continue back out to the outer solar system to get to Jupiter. In fact, Venus and Mercury are between the Earth and Jupiter. The way they are now, Venus and Mercury aren’t just closer to the Sun, but they’re also closer to Jupiter than Earth is!
If you can, try to get out there and see these alignments before they disappear for a while. I’d love to hear what you think and hear about what you see. Thanks again for stopping by. Also, a special thanks to the people who are new around here and just started to read along. Thanks for taking the time.
Clear skies, everyone!