July 15, 2024

The Lyrid Meteor Shower

Every April 22nd, the night skies in both hemispheres are lit up with a streaky series of fiery trails. This is the Lyrid Meteor Shower.

Lyrid Meteor Shower

Richmond, Virginia is one of America’s oldest, and most historically important, cities. Founded in 1737, the city would play a key role in both the American Revolution, and the Civil War.

In 1775, American Nationalist Patrick Henry delivered his famous ‘Give me Liberty or give me death,’ speech, at St John’s Church, later seen as a key catalyst for rousing support for the Revolution.

Richmond, before the outbreak of the Civil War

By the middle of the following century, the city would serve as the Capital of the Southern Confederate States, when they broke with the rest of the American Union and triggered the Civil War. A scant 100 miles south of the Northern capital, Washington, its location would prove provocative, and would lead several northern military commanders to rashly decide on an all out assault on the city (each time unsuccessfully).

Between these dates, in 1803, the city bore witness to an extraordinary meteor event, the first recorded in American history.

Artists rendering of a 19th century meteor shower

Around 3am, on the night of April 20 of that year, the citizens of Richmond were roused by a fire alarm. As people rushed out into the street to see what was happening, they were stunned to find the night sky ablaze with shooting stars.

‘Shooting stars were observed on Wednesday morning last at Richmond and its vicinity, in a manner that alarmed many, and astonished every person that beheld it.

From 1 to 3 in the morning, those starry meteors seemed to fall from every point in the heavens, in such numbers as to resemble a shower of sky rockets.’

- Eyewitness account, reported in the local press

The citizens of Richmond, had just had a particularly vivid encounter with the Lyrid meteor shower (the shower is named after the constellation 'Lyra').

But it was not the first, known from recorded history.

The Lyrid Meteor Shower,  location.

As early as 687 BCE, Chinese astronomers left a written account of a display of shooting stars, that is strongly thought to be the earliest account of the Lyrids.

The position in the sky, originating near the star Vega and depicted diagrammatically, and the time of year, provide convincing proof (another account from China dates from the year 15 BCE).

A similar account of the Lyrids comes from Korea, from the year 1136.

So if the Lyrid Meteor Shower has been with us every April, for 2700 years, where does it originate from?

Comet Thatcher's eccentric orbit

Comet Thatcher has a distinctly eccentric orbit, even by the standards of other comets.

Inclined at a sharp angle to the plane of the planets, the narrow band that all planetary orbits around the sun fall into, Thatcher effectively approaches the solar system form above. It then makes a shallow dip below the sun, before retreating back to interplanetary space.

It’s highly elongated path means it only visits our solar system every 400 years.

Artist's rendering of Thatcher's Comet, 1861

The last time it appeared was in 1861; which marked its closest recorded approach to the Earth. On this trip, it was discovered by, and named after, American amateur astronomer A.E. Thatcher.

Thatcher found it using a simple pair of binoculars and was able to spot the comet before it was visible to the naked eye. It duly appeared in April, and was visible for a few days; wide, stubby, and with a short, broad tail.

It will not return until the year 2276.

This appearance of the comet was widely reported in the press, and much discussed.

And so, from the following year, when the annual meteor shower appeared at the same time as the comet had, the year before, the connection was able to be made.

Comet Thatcher leaves an effective vapor trail in space; only it is not made out of gas, but rather small pieces of ice and rock, that have broken off the comet itself. The comet’s orbit is so well worn, that there is a track of this debris permanently in space, marking its path.

And every year, on April 22, earth’s atmosphere collides with this debris trail, as we orbit the sun.

The result is a remarkable celestial display, one that was enjoyed in Zhou Dynasty China, and Koryo period Korea, and pre Civil War Virginia, and just outside Melbourne, in 2018.


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