Did you shower today? This is not that kind of shower….
If showers are your thing, then you’ll be thrilled to hear August premiers of the most visually dramatic and inspiring cosmic spectacles of the year.
The Perseid Meteor Shower.
For those of you who stare up at the night sky and marvel at the vastness of the universe, it’s an opportunity to view one of the many wonders the third rock from the sun experiences.
The Perseid Meteor Shower, also known as The Perseids, perhaps one of the most popular meteor showers of the year, visible to naked eye between July and August. With clear skies it’s possible to see one of the most spectacular cosmic light shows, courtesy of the Swift-Tuttle comet.
According to the American Meteor Society, the shower will peak between August 11-12 this year when American spectators can expect to see the greatest number of meteors.
Unfortunately, this year’s meteor extravaganza won’t be quite as awe-inspiring as the shower will be competing with a full moon illuminating the night sky.
What, exactly, causes this cosmic light show every year?
I’m glad you asked!
Every year, Earth transits the path of comet Swift-Tuttle, from July 17 to August 24, the densest and dustiest area passed through August 11-12, the shower’s peak viewing opportunity.
What this means for night viewers is you can see the most meteors in the shortest amount of time. When the moon isn’t visible you’d normally see higher rates of meteors per hour, and in some instances (such as 2016) we may experience what’s known as a meteor outburst or meteor storm, which can produce at least 1,000 meteors per hour!
So, what is comet Swift-Tuttle?
Let’s begin with comets. Generally speaking.
Remember as kids when we’d await the ice cream truck, delighting in the summer treat of a snow cone? That delectable frozen treat, little more than shaved ice drenched in colored sweetness, turning our lips and tongues various shades of blue, green and red.
Well, think of a comet as a really big snow cone, absent the tinted syrup! With a few more additives for good measure.
Current understanding is comets are frozen leftovers from the formation of the solar system, which are composed of ices, rock, dust and gases, orbiting our sun. Not quite as tasty (or edible) as snow cones.
Comets can range in size, those we’ve identified and catalogued, anywhere from a few miles to tens of miles wide. That’s a BIG snow cone! When the comet’s orbit brings it in close proximity to the Sun it heats up and spews dust and gases, creating a giant glowing head larger than most planets and forming a tail stretching for millions of miles.
Some comets are periodic, which means they have a closed orbit around the sun and complete that orbit in less than 200 years.
Astronomers believe there may be billions of comets orbiting our Sun in the Kuiper Belt (pronounced ky-per), a belt surrounding our outer solar system believed to be a mostly flat-plane or disc, and the even more distant Oort Cloud, a more spherical shell and vastly larger, surrounding the rest of the solar system, including the Kuiper Belt!
Which brings us to comet Swift-Tuttle.
Originally labeled comet 109P, the comet was discovered in 1862 independently by astronomers Lewis Swift and Horace Tuttle.
Comet Swift-Tuttle is a large comet, with a core measuring approximately 16 miles in diameter, almost twice the size of Washington, DC! Okay, so the District of Columbia is a square, but that gives you an idea just how big Swift-Tuttle is!
The “P” in comet Swift-Tuttle’s original designation 109P identifies it as a periodic comet, completing its orbit around the Sun every 133 years, and the 109 denoting it was the 109th comet to be identified in the year 1862.
What’s even more amazing is historical records from China indicate it was seen in 69 BC and again in 188 AD and was probably visible to the naked eye in 322 BC. When it was discovered (or rediscovered?) in 1862 it was as bright as Polaris.
Comet Swift-Tuttle’s orbit that makes repeated close approaches to Earth, some closer than others, and was considered at one point a potential threat as a near-Earth object capable of striking the Earth. Fortunately for us its orbit is sufficiently stable that we needn’t concern ourselves with any collisions any time soon!
Now that we know where the Perseid Meteor Shower originates, why do we call it The Perseid Meteor Shower, or The Perseids for short?
What a great question!
First, the spectacle that is a meteor shower, or falling or shooting stars, is caused by tiny dust trains entering Earth’s atmosphere as the Earth is passing through the meteor’s dust trail. As the debris enters the upper atmosphere, friction with the air causes each particle to heat and burn up. We see the result as a meteor.
The shower itself is named for the constellation Perseus, which is its radiant. A radiant is the point of origin of the meteor shower from our visual perspective on Earth, not its actual origin, so Perseid meteors appear to traveling away from the constellation in the night sky.
Locating Perseus in the night sky will help narrow your focus to see as many meteors as possible.
If you’re not certain how to locate the constellation Perseus, give a locator app a try, such as Star Walk 2 Free or Star Tracker, both of which work on Android or iOS.
The Perseid Meteor Shower is considered to have the brightest and most numerous meteors of all the showers we experience.
This year will be challenging to view because August will see the full Sturgeon Moon, beginning the night of August 11, the first night of the Perseids peak. This means the peak will be considerably washed out by the light of the moon. The full moon rises about sunset and sets around sunrise the next morning, so your best chance of seeing meteors in a dark sky will be in the dark hours before dawn, when the moon is low.
Don’t worry if you miss out this year, you’ll have another chance again next year, and maybe the moon will cooperate and take a holiday while we search the skies for the magnificence of The Perseid Meteor Shower.
Happy meteor hunting!