Hmm…what to write about? I finished my series on evolution…I have a couple other things I’m working on, but they aren’t ready yet…what’s in the news? Oh, there’s a transit of Mercury tomorrow. I guess that’s the biggest science news of the week.
Okay, so, it is pretty interesting. You see, Mercury’s orbit is such that it crosses the Sun as seen from Earth about thirteen times every hundred years. That’s once every seven and a half years on average, but there’s a lot of randomness involved.
Actually, no, it’s the exact opposite of random. We can predict Mercury’s orbit centuries in advance. The point is that the time between transits varies a lot because the orbits align in different ways from one year to the next. It turns out the next transit of Mercury is thirteen years from now in 2032. (The last one was just three years ago in 2016.) So see it before it’s gone, I guess. Here in the D.C. area, it will begin at 7:36 AM Eastern Time and end at 1:04 PM. That will vary a little depending on your location, as Earth passes through Mercury’s “shadow,” but that will only be by a couple minutes.
To be honest, I wasn’t that enthused about making a post on this. Personally, I find the story about how astronomers in Spain figured out a new way to measure the expansion of the universe (and they still can’t get the various methods to agree with each other) to be much more interesting. (Maybe next post.) The transit of Mercury isn’t so exciting because while it’s notable, it’s actually rather difficult to observe. Even if you kept your dark eclipse glasses from two years ago, you almost certainly won’t be able to see. I could just barely see the transit of Venus back in 2012 with my “naked” eyes (which were really eclipse-glassed eyes, just without a solar telescope), and Venus looks five times as big as Mercury on the disk of the Sun. The transit of Mercury will be pretty much invisible with the equipment most people have at home.
(Warning: everyone knows don’t look at the Sun, etc., etc., but the important thing to remember is: Don’t look at the Sun through binoculars or a telescope without a dark filter on the front end. Eclipse glasses will not work that way and might melt or do other bad things to your eyes.)
So how can you see the transit of Mercury? Well, the simplest way would be to seek out your local astronomy club. Most such clubs will probably be running some kind of event for it. If they’re not, or if you don’t have an astronomy club in your area…I don’t really know. You can try to make a pinhole projector—and you don’t need a cardboard box to do that. You can just project from one sheet of paper onto another one—but it’s the same problem: I don’t know if you’d be able to see it on an image that small.
Or, maybe the simplest option of all in this day and age: you can watch it online.
Happy observing, and I wish you clear skies.