A total eclipse... of Mars?

This month brings skywatchers a rare sight: a total eclipse of the red planet Mars by our Moon. The event is visible across much of North America, and is the only event of its kind all year.

As the Moon orbits our planet, it gets in the way of all sorts of other celestial objects that are farther away. When the moon blocks out the sun, we call it a solar eclipse, but a more general term is occultation. (“Occult” means “hidden”, so it makes sense. One object is hiding another.) The moon occults dozens of stars every month, but it’s fairly rare that things line up just right so that the Moon occults a planet. This month, we’ll see the thin crescent Moon occult Mars, early on the morning of Tuesday, February 18th. Here’s how to spot it yourself.

If you have a telescope, crank up the magnification as high as you can and you will be able to see Mars as a tiny disk, almost fully illuminated. At high power, you can watch the edge of the moon actually move across Mars over those 14 seconds. Eclipse should happen about 6:02 am Manitoba time, plus or minus a minute or so depending on where you are in the province.

Then it’s time to wait around for an hour or so, as the Moon continues its orbital motion and the earth continues its rotation. The moon will rise higher into the southern sky; the sky will brighten, and sunrise twilight will approach. But, about 7:19 am Manitoba time, Mars will begin to reappear from behind the dark edge of the moon, slowly fading in over the 14 seconds or so of the occultation.

If you have a telescope, you can probably take pictures of the event with your phone held up to the eyepiece. Post your images to the Manitoba Museum’s Facebook, Twitter, or Instagram accounts – we’d love to see them!

Thursday, November 20, 2019 may provide a rare meteor outburst – but only for a few minutes.

The annual Monocerotid meteor shower normally produces about 1 or 2 meteors per hour – and that’s if the sky is dark with no moon. It’s not something some skywatchers would even bother to put on the calendar. In the last couple of decades, however, astronomers have begun to understand meteor showers in more detail, and can predict when activity may pick up. This year, an outburst is predicted to occur at 10:50 p.m. Central Standard Time, and southern Manitoba is predicted to be cloud-free. So what’s going on?

A meteor (or shooting star, or falling star – they all mean the same thing) is caused when the Earth slams into a piece of interplanetary dust about the size of a grain of sand. Space isn’t totally empty – besides planets, and asteroids, and comets, there’s also smaller stuff, down to the size of microscopic dust particles. These tiny particles burn up when they hit the earth because they’re travelling at 40,000 km/h. Just the friction of passing through the air heats them up so much that they vaporize and create a trail of light that we can see from the ground. On a given night, you might see a half-dozen of these per hour if you watch the sky carefully from a dark location. Most of the time, we don’t notice these because we’re not watching the sky carefully, or nearby lights interfere and make it hard to see them.

So, one piece of dust = one meteor. It doesn’t take much of a logical leap to see that more dust means more meteors. If the earth goes through a big cloud of dust, a whole bunch of meteors will happen all on the same night. That is a meteor shower. Each year on the same night, Earth is in the same spot, and goes through the same dust bunny, creating an annual meteor shower.

Through careful analysis, astronomers have determined that the Moncerotid meteor shower has a very dense clump in it, that usually the earth just skims the edge of. But, as gravity adjusts the particles each time the Earth goes by, things change, and so this year we’re expected to hit the dense clump head-on.

For the best view, you want to dress up warm, and head out of the city to a dark location. Bring a reclining lawn chair or something so you can lean back and look at at the whole sky at once. (Try to stay off the ground, which will suck heat out of you and make you cold very quickly.) Point your feet generally southeast (towards Orion the hunter, if you know your constellations) and look straight up. Don’t look at your phone, because even a quick peek will kill your night vision and maybe make you miss the whole thing.

The time is somewhat uncertain, so be prepared to stay outside in Manitoba November night temperatures for a couple of hours. I’m going to start watching about 10pm and watch until midnight (or until t happens).

Short answer: we won’t know for sure until it happens. But, if the prediction is correct, you’ll see the stars at first. Orion will be visible in the south, and other constellations of the winter sky as well. The brightest star in the sky, Sirius, will be just rising below Orion.  Farther left (almost due east) is another bright star, Procyon. Occasionally, you will see a shooting star flash through your field of view. As the time gets closer, you’ll see meteors more often, and the interval between them will shrink. One every 5 minutes, then 1 every couple of minutes… then two or three a minute. If you trace them backwards, they all seem to radiate from a point near Procyon. If the prediction pans out, at the peak you might be seeing 5-10 meteors per minute for several minutes around 10:50 p.m. Then, the rate will subside, back to a couple a minute, and then one every few minuets, and then back to one every 10 minutes or so.

Or, maybe nothing will happen – the Earth might miss the dust bunny completely.

Or… maybe the dust bunny is even denser than we thought, and we’ll see even more meteors than predicted. Who knows?

For more information on this shower, visit the International Meteor Organization’s page. You can also find info there on how to count meteors and contribute to the science of understanding these rare and unpredictable natural spectacles.