It’s the year’s best time to observe the innermost planet

As Mercury spins, it has no axial tilt. (NASA)

As Mercury spins, it has no axial tilt. (NASA)

The innermost planet is weird in so many ways, it’s hard to find aspects that aren’t strange.

This is the year’s best time to see Mercury as an evening star. It’s strangely satisfying, and there’s no rush. But you do need an unobstructed horizon. Go out at 8 p.m. sharp. From then until 8:15, that’s your window. Look low toward where the Sun set.

The time is important. Twilight deepens as dusk progresses, which makes finding Mercury easier; and yet it’s sinking lower all the while. You want the right balance. And although it’s theoretically visible most of April, a good time to begin is next Friday, April 8. Mark it on your calendar. That’s when Mercury hovers to the right of the hair-thin crescent Moon.


Occupying the faint constellation Aries, it’s the only star low in the direction of sunset. Did we say that you need a clear view, almost all the way down to the horizon? All the mall parking lots of Kingston provide this.

I don’t know why, but seeing Mercury creates a special feeling. A few years ago, driving in Florida with some elderly relatives, I suddenly spotted it, and screeched the car off the highway and onto the shoulder. I had to stop before an upcoming overpass blocked the view. Those back-seat people were screaming, “What’s wrong? What are you doing?” I had to tell them that it was Mercury: “Look! That orange star down low! Can you see it?”

After next Friday, the 8th, Mercury gets higher but loses brilliance. Nonetheless, around Tax Day, April 15, it’s still magnitude zero, and now ten degrees up. That’s a good time to look, too.

Mercury has the most lopsided, out-of-round orbit of any planet. Thanks to tugs from Jupiter, the Mercury orbit wildly changes shape. In the future its orbit may stretch all the way out and let it collide with Venus, destroying both worlds in the next five billion years.

Mercury alters its brightness more than any other planet, varying a thousandfold. And while Venus looks brightest when it’s near to us, Mercury shines most brightly when it’s farthest from us – like right now.

As Mercury spins, it has no axial tilt. At its polar depressions, the Sun is always below the horizon, so these regions are packed with ice. They offer winter sports on a world badly needing it.

And even that isn’t the end of Mercurian strangeness. It has a region called the Weird Terrain. I’m not making that up. It’s located at the precise opposite point on Mercury from its most famous impact crater, the enormous Caloris Basin. Apparently, debris or else shock waves from that impacting meteor traveled around the planet and collided in mid-air at the antipodal point – to wreak havoc there.

Go out at the end of next week and look very low in the west. See that strange orange planet for yourself.