Satellites in a Train

Winnipeg residents have been reporting some unusual sightings in the night sky over the past few days. Bright star-like objects have been seen moving across the sky, following each other in a train. Sometimes half a dozen or more of them are visible at the same time. What are these?

Unfortunately, they won’t be “unusual” for very long. These are the StarLink satellites, launched by Elon Musk’s Space-X to deliver internet to remote corners of the globe. 60 satellites at a time are put up by the company’s Falcon-9 rocket, and they slowly spread out in a circle around the earth. For the first couple of weeks after launch, they are relatively close together, and all appear to travel in the same path across the sky. As of today, there are 362 of these satellites, but the plan is for 12,000 of them. As in, twice as many satellites as the number of stars you could see from a perfectly dark location.

And did we mention that each one is one of the brightest objects in the sky? They shine at about magnitude 1 or brighter, which means they’re brighter than the stars of the Big Dipper and as bright as the brighter stars. Only the planets and the moon, and maybe a few stars, will outshine a StarLink satellite.

It’s pretty easy to spot these satellites when they happen to be going over your town. Visit www.heavens-above.com and set it to your location, and you’ll get a list of all of the satellites visible that night. StarLink will make up a big chunk of that list. For example, from Winnipeg between 9:25 pm and 9:45 pm on Monday night, March 30, there will be 44 StarLink satellites visible (plus a few other satellites). The sky is getting to be a busy place!

StarLink has brought criticism from astronomers, who are already finding interference with the satellites getting into their field-of-view while trying to do science. Those concerned with the amount of space junk in orbit are also concerned, as none of these satellites has a re-entry plan and will just stay up there, cluttering orbit and posing a risk to any other satellites launched, including any attempts to send robots or humans to the other planets. We’re basically building a cage around the Earth, with StarLink satellites as the bars.

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.

by Claire Woodbury, Science Communicator

“Once upon a time there was a beautiful and talented weaver, the daughter of the Sky King. She met and fell in love with a handsome and skilled herdsman. They were so devoted to each other that they neglected all else. The weaver stopped weaving and the herdsmen let his animals wander all over the place. The Sky King didn’t approve of this behaviour, and separated the lovers on either side of the heavenly river. His daughter was heartbroken and despondent so the Sky King relented and allowed the couple to meet, but only once a year. Every year, on the seventh day of the seventh lunar month, a flock of magpies would fly into the sky and create a bridge, allowing the lovers to cross the heavenly river and be together.”

This classic tale of “boy meets girl, Dad doesn’t approve”, has been told since the 2nd century B.C.E. and celebrated in summer festivals in China, Japan, and Korea. You can read this story every night in the summer sky. The “heavenly” river that separates the young couple is the Milky Way.  The lovers are represented by the stars Vega and Altair, two points in the asterism known as the Summer Triangle. The triangle shape is actually made up of the three brightest stars from three different constellations, Cygnus the Swan, Lyra the Harp,  and Aquila the Eagle. In the city, it is often difficult to see all of the very faint stars of these patterns but the brightest from each are visible on clear nights. The brightest is Vega, the dimmest Deneb, and Altair makes up the point of the triangle.  You can find the Summer Triangle higher overhead, across the sky from the Big Dipper all summer long and even into autumn.

by Claire Woodbury, Science Communicator

The highlight of August sky observing is the Perseid meteor shower. A meteor shower is a high occurrence of shooting stars over several days. Of course, “shooting stars” aren’t really stars at all, but dust-sized bits of rock or metal (meteoroids) that collide with the earth and burn up in our atmosphere. As they vaporize, they cause a brief streak of light in the sky (a meteor) which can be seen from the ground. Rarely, a larger version of a meteoroid survives its time as a meteor and makes it to the ground intact; we call these meteorites. Confused with the similar-sounding names? The long and short of it is that dust from space burn up in our atmosphere, making brilliant flashes of light that result in a spectacular cosmic show.

But where do these specks of dust come from and why do they sometimes come down all at once in a shower? The answer lies in the earth’s yearly path around the sun. The earth orbits the sun and acts as a cosmic broom to any smaller objects in its path. It just so happens that between mid July and mid August every year, Earth is travelling through the trail of dust left behind by a comet. Comets are balls of ice and dust that orbit the sun. Small chunks can break off as the comet travels through space. When we pass into the path left over from its travels, those chunks collide with the  earth. The Perseids are caused from dust and debris left over from Comet Swift-Tuttle (109P).

It depends. The maximum number of meteors you could see depends on how dark your sky is, what time you observe, and how long you watch. It’s best to get away from city lights, since the fainter meteors are easy to miss when there are bright lights around. Although we are moving through the densest part of the dust trail on the evening of the 12th, meteor showers are always better after local midnight due to the orbital geometry. Your best bet will be between 11 pm and 4 am on the night of August 12-13, with rates increasing towards dawn. You might see upwards of 50 meteors an hour.

Don’t expect to see a constant stream of meteors; you might see one then nothing for twenty minutes then a whole bunch. Don’t give up if you haven’t seen any, best practice is to observe for at least an hour.

The best thing about meteor showers is that you don’t need any specials tools to see them! Just relax, grab a lawn chair or a blanket (and maybe some bug spray, let’s face it, this is Manitoba after all), lean back and look at the sky! Your ability to see the streaks of light can be hampered by clouds, high buildings, or light pollution. Even a particularly bright moon can obscure your view. Luckily for us, the moon will be very new on the evening of the 12, allowing for near perfect viewing conditions. August 12^th between midnight and dawn (morning of the 13^th) is the night you will see the most meteors but you can actually start to see the Perseids every night as early as July 17^rd and as late as August 24^th as we move in and out of Swift-Tuttle’s path. If you’re worried about missing the big show, you can start to practice by doing a little meteor gazing every night.