For the Love of Mercury!

That title sounds like something out of Alice in Wonderland. Ah well. No matter.

Hey, Sky Fans! I hope you had a great weekend, and have a great week ahead to look forward to. Thanks for stopping by on, what is around here, a very rainy Monday. At least the clouds have finally had the decency to do something other than just block out the night.

About a year ago, my family finished up dinner early on a warm and clear evening. The sun was on its way down behind the hills. The kids had no homework or soccer games. The dishes and tomorrow’s lunches were done, and we had one of those wonderful moments to just be. At the end of what I remember as a difficult week, I was releived that 14 billion years of evolution had led the univese to that point.

There’s a riverwalk park a couple of miles away that’s one my favorite places to watch the skies. The waters wind their way through the hills on both sides of the river, and for a good, long stretch up toward the houses, shops, and people shuffling between, it’s not clear if you’re looking west or north; at hills on this side, or on that. It’s a little disorienting, albeit in a good way. Other than a few straggling commuters in ties and blazers spending the last of the daylight casting lines into the current, we had the park to ourseleves; free to chase around soccer balls and be hit in the face by frisbees hiding in the shadows. As we played, I grabbed this photo.

Mercury at Sunset

That bright dot in the purple is the planet Mercury. Finding Mercury (terrific, photo-filled blog post, but a lousy band name) is one of my favorite things to do under the skies. It’s a challenge, and lots of people I’ve spoken to didn’t even know they could.

It’s so close to sun that the two never appear more than a short distance apart in our sky. So, it always sets just a short time before or after the sun does. It’s small; only a little bit bigger than the moon, but over 200 times farther away, on average. On top of all that, it moves fast. It speeds around the sun in just 88 Earth days, more than four times every Earth year. For comparison, that’s about the same relative difference in orbital speed, that the good and generous folks on Ceres, far off in the asteroid belt beyond Mars, see us move in their sky. This means, Mercury moves from one spot in the twilight to the next very quickly from night to night. Add all of this together, throw in the sun’s glare, and you’ve got a real challenge on your hands.

It’s tough, but not impossible. If you want to give it a shot for yourself, these closing days of March and opening days of April are the best chance you’ll have all year. Mercury is rising into the dusk, and will reach what’s called greatest eastern elongation on April 1.

A planet’s elongation is its apparent distance from the sun in the sky. This only applies to Venus and Mercury, because they’re inferior to Earth, closer to the sun, and our perspective on them is more closely to tied to our view of the sun than our views of the superior planets are. Eastern elongation is, as an exciting twist, the distance from the sun in the western (evening) sky.

As Mercury appears to get farther from the sun, it rises higher and sets later. Since it moves so fast, with a snap, it’ll be gone from the evenings until summertime by mid-month.

For my sky-watching dime, the best night of the bunch will be this Wednesday, March 29. Mercury and Mars, which, itself, has an exciting month ahead, will meet up with with a very thin, barely there, crescent moon in the west’s deepening dusk. If you head out after the sunset, possibly as late as about 7:45, and have a good view of the lower reaches of the sky, just above horizon, you should have a chance to see the three in a broad triangle, with Mercury leading the charge toward the horizon. The skies are still getting dark early enough for you to have a good chance. A pair of binoculars could help.

Mercury, Mars, and the Moon, March 29. 2017
Mercury, Mars, and the Moon, March 29, 2017

As we headed home that night, me nursing a bruise under my eye, Mercury was gone by the time we hopped out of the car. It’s funny how those peaceful times can be so necessary, but so hard to find sometimes. Even just the few minutes that can exist between chaos and exhausted plotzing (not to say they’re mutually exclusive) can be magic. Maybe if you need a few mintues, you can head out there and see what you can see.

Clear skies, everyone!


5 thoughts on “For the Love of Mercury!

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