The Perseid meteor shower is one of the biggest spectacles of the year and even if you’re not into astronomy you have probably heard something about it. However, once I started digging in a little further the story got a little more interesting…
Quick facts about the Perseids Meteor Shower:
- Comet of Origin: 109P/Swift-Tuttle
- Meteor Shower period: July 17 to August 24th
- Meteor shower Peaks: Aug. 12-13, 2015
- Peak Activity Meteor Count: Up to 100 meteors per hour
- Look North / North-East late at night (after 10 p.m EST)
- Comet Swift-Tuttle has the mass of about 7 cars
- Comet takes 133 years to orbit the sun
- Travelling roughly at 58 km/s or 36 mi/s
- Will make closest approach in the year 2126 and 4479
- If it impacted Earth it would be 27 times more powerful than the asteroid that took out the dinosaurs
So without further adieu let’s talk about what Perseid meteor shower is, where it originated from, and the extensive history behind it.
Where Did Perseid Meteor Shower Come From?
A common question that gets asked all the time. Nonetheless, a good question. The Perseid Meteor shower is actually debris and pieces falling off comet Swift-Tuttle passing by at 58 km/s or 36 mi/s. I find that unbelievable in its own right as we get this beautiful display of meteorites burning up in the mesosphere, which is only 80 km or 49 miles above our fragile heads.
Even still where did this comet come from? Well comets are what we call “dirty snowballs.” They are comprised mostly of gas, ice, and rock. Comet Swift-Tuttle is actually a periodic comet that takes 133 years to orbit the sun. It has an orbital ressonance of 1:11 with Jupiter. In plain english that means the time it takes Jupiter to orbit our sun 11 times (12 years per orbit) comet Swift-Tuttle will have orbited the sun just once.
The Great Discovery of Comet Swift-Tuttle
In 1862 the comet was discovered by Lewis Swift on July 16 and then a few days later by Horace Parnell Tuttle on July 19th. Astronomer believe there was a connection between this comet and the meteor showers that happened every August. It was later confirmed in 1992 when a japanese astronomer spotted this comet with his 6 inch binoculars as the comet passed 177 million km or about 100 million miles away from Earth.
The intriguing part to me is how bright the comet look at various times in history. The apparent magnitude of the comet, or how bright it looks in the sky relative to other objects, in 69 B.C.E was 0.1 mag. To give you a frame of reference if you look at Vega in the night sky it is considered a magnitude of 0.03. Basically, the comet was as bright as an airplane in the sky and very easy to see with the naked eye.
In the year 2126 the comet will make its next closest approach and have an apparent magnitude of 0.7.
The Potential Threat of Comet Swift-Tuttle
One of the biggest threats to Earth is this comet. No joke. This was something I never knew about personally but creates quite the context of the Perseid Meteor shower.
The comet is actually on an orbit that makes repeated approaches drawing nearer and nearer to the Earth-Moon system. When it was sighted in 1992 it was off by 17 days, which may not sound like a big deal at first but it is. Reason being is the next approach is in 2126 and could mean they may be off by an additional 15 days which can result in a collision with Earth or the Moon.
By the way, if this comet hit Earth it would be at least 27 times harder than the asteroid that took out the dinosaurs. Check out the image below. It would be about 27x bigger than this impact!
So you can see that things started to get a little more stressful real fast for astronomers trying to figure out if this comet would collide with Earth or not one day. It turns out that the astronomers did some digging and looked back at the sighting in China in 69 B.C.E along with all the other observations up until 1992 and discovered that it posed no threat in 2126.
Phew. Even though it’s not our problem it’s still our race at the end of the day and that is still precious to us.
Nevertheless, we’re not quite in the clear. 2000 years later in 4479 the comet will pass within 0.03 AU of Earth or about 4 million km or 2.4 million miles. The biggest worry about this is that it’s not a solid prediction (as you can imagine predicting a comet’s trajectory 2000 years from now). It’s almost a 0% chance of hitting Earth in 4479 but of course 2000 years is a long time for trajectories to change as well as refining the predictions. The last thing we would ever want to face is a comet headed for us or the Moon.
Even though Perseid Meteor shower is one of the most spectacular events of the year, it’s also a constant reminder of what could destroy our planet and life on Earth.
Sources used for this article:
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