Location of the Ursid (URS) radiant on December 21/22, looking slightly east (right) of due north. (American Meteor Society)
Look up! Tonight into tomorrow, in addition to the Great Conjunction, we’ll be moving through the peak of the Ursid Meteor Shower. The peak of this shower is expected late tonight, from 11:00 PM Monday 21st December through 3:00 AM Tuesday 22nd December 2020.
What is the Ursid Meteor Shower?
The Ursids are a relatively new meteor shower, according to EarthSky.org‘s skywatching guide. While many of the meteor showers we see throughout the year have been annual occurrences for centuries, the Ursids weren’t observed until the 20th century.
The meteor shower happens when Earth passes close to the orbit of comet 8P/Tuttle and this year, our close pass includes several trails of debris that also follow this comet, according to the American Meteor Society. This could cause more activity during the meteor shower.
Where Do Meteors Come From?
The Ursids are named after the constellation Ursa Minor, the little bear, which marks the region of the sky from which meteors will appear to radiate. Specifically, the shooting stars will seem to come from just to the left of the bowl of the Big Dipper, the popular asterism that makes up part of Ursa Minor. During the peak, the dipper will hang low in the northern sky for mid-latitude observers.
Meteors come from leftover comet particles and bits from broken asteroids. When comets come around the sun, the dust they emit gradually spreads into a dusty trail around their orbits. Every year the Earth passes through these debris trails, which allows the bits to collide with our atmosphere where they disintegrate to create fiery and colorful streaks in the sky.
The Ursids Peak
Meteor showers are very predictable events, so astronomers know exactly when you have the best chance of seeing them.
The Ursids meteor shower is active annually between December 17th and December 24th. The shower usually peaks around December 23rd, but in 2020, the Ursids will peak overnight between the 21st and 22nd December. At its peak, observers may be able to view as many as 10 meteors in an hour.
Conditions for Viewing
You can look up at the night sky nearly every night this week to see if you can catch a glimpse of a meteor. Generally, the best times for viewing will be between 11:00 PM and sunrise, which is generally from 5:50 PM through 6:15 AM this week.
But, there are impediments for viewing in Trinidad and Tobago tonight.
Firstly, light pollution is a major issue in most populated areas across Western and Northern Trinidad, as well as the Western half of Tobago. Unfortunately, there is little you can do about this beyond traveling into darker areas such as parts of Northern Coastal Trinidad or Eastern and Southern parts of the island.
Secondly, a surface to low-level trough is forecast to continue affecting the Windward Islands, including T&T tonight.
This means partly to mostly cloudy skies, with models showing few areas with 30-50% cloud cover across parts of Central and Northern Trinidad with most areas experiencing 70-90% cloud cover and even periods of showers, briskly moving across both islands. Heavier rainfall is forecast to favor the southern and eastern areas of both islands.
Look Toward the North
Generally, the Ursids are a low-key affair, offering perhaps as many as five to 10 meteors per hour in a dark sky. In rare instances, bursts of 100 or more meteors per hour have been observed at times over the past century.
You can use an AR app like Night Sky on your smartphone to track down the constellation. The best place to look is to the north and north-northeast and near the horizon, gradually moving higher into the skies as the night into morning progresses.
It’s Meteors – Not an Asteroid to Comet
It may be self-explanatory, as it is literally in the name of the shower, but the “shooting stars” you may see in the skies over the next several nights are meteors.
The terminology of these space objects matter, as a meteorite would have impacts to land, while a meteor does not.
Meteor and meteorite strikes are more common than you might think. Dust-grain size meteoroids strike the Earth’s atmosphere almost constantly, but they often go unnoticed. Meteoroids between a millimeter and a centimeter burn up in the atmosphere and appear to us as shooting stars.
Larger strikes are less common—a one-meter meteoroid strikes the Earth once each year on average and would reach the ground as smaller debris, while a 100-meter meteoroid strikes the Earth approximately every 10,000 years, according to a Tufts University fact sheet. Meteoroids over 1 kilometer hitting Earth are catastrophic events that occur every 1 million years on average.
Meteoroids do not discriminate where they land, nor where they enter the earth’s atmosphere. Hence, it is well within the possibility that events such as this could happen across Trinidad, Tobago, or any other Caribbean islands.
But medium-size strikes can be dramatic spectacles—and in some cases, dangerous. The Chelyabinsk meteor that struck southern Russia in February 2013 blew out windows and caused indirect injuries to almost 1,500 people.
Tips for Viewing
1. Realize that this shower rises gradually to its peak. Few meteor showers are a one-night event. You could start tonight!
2. Be aware of the time of moonset each night. As much as possible, in the weeks between now and the peak, you’ll want to be out looking after moonset.
3. Watch in the hours before dawn Most meteor showers are best after midnight, and the Ursids are no exception. After midnight, the part of Earth you’re standing on has turned into the meteor stream, which means the radiant point for the shower will be above your horizon.
4. Avoid city lights. This should go without saying, but just a reminder. A wide-open area – a field or a lonely country road – is best if you’re serious about watching meteors.
5. Camp! Nothing beats a set-up before the night begins. Of course, you’ll never see as many meteors in the evening as you will after midnight, but – if you are watching during the evening hours – you might catch an earthgrazer, which is a slow-moving and long-lasting meteor, traveling horizontally across your sky. Earthgrazers might be seen even in bright moonlight. They tend to be seen in the late evening or around midnight.
6. Make yourself comfortable. Sprawl out upon a reclining lawn chair, with an open sky view. Bring along a blanket or sleeping bag. Your eyes can take as long as 20 minutes to adapt to the dark, so give yourself at least an hour of observation time.
7. Watch with friend or friends, and try facing in different directions so that if someone sees a meteor, that person can call out – “meteor!” – to the rest.
8. Notice the meteors’ speeds and colors, and watch for meteor trains. A meteor train is a persistent glow in the air, left by some meteors after they have faded from view. Trains are caused by luminous ionized matter left in the wake of this incoming space debris. They linger for a moment or two after the meteor has gone.
9. Embrace the night. We hear people bubble with excitement about seeing meteors in all sorts of conditions – moon or no moon – city lights or no city lights. So, camp out and make a night of it! Read more.
Check out other stories on celestial events.