Science in the Bluegrass —
‘Did you see the Tears of St. Lawrence?’

Chris Graney

Did you see the tears of St. Lawrence last week?

The “Tears of St. Lawrence” is an old name for the Perseid meteor shower. The Perseid shower peaks every year on the morning of Aug. 12 (more or less). It is named for the constellation of Perseus, in the region of the sky where the meteors appear to originate.

For a long time — dating back to Aristotle at least — astronomers did not consider meteors to be an astronomical phenomenon. Meteors were thought to be a wholly atmospheric phenomenon, like clouds or rainbows or lightning. Think of the name meteor. Who does the weather forecast on your local TV news? The meteorologist — a scientist who studies the atmosphere.

But in 1833, on the night of Nov. 12-13, there was a meteor storm. Meteors flashed across the sky at a rate of over 1,000 per minute. That is tens of meteors each second. Multiple meteors would be visible in the sky at any given moment.

This event captured the interest of a lot of people, including astronomers. This interest in meteors led several astronomers to independently figure out that there was a recurring meteor shower in August.

But one of those astronomers also discovered that, in the Catholic areas of Franconia and Saxony in Europe, some people had long recognized the recurring August meteor shower. They had associated it with the feast of St. Lawrence, the 3rd-century martyr who was executed by being roasted alive over a fire. He reportedly had the lip to tell his executioners, while he was being cooked, to roll him over lest they cook him unevenly!

Thus, average Catholic people were the first to discover that meteors were not just an atmospheric phenomenon like a cloud or rainbow or lightning, but rather that meteors could be a regularly occurring thing. These people knew of the annual feast of St. Lawrence, Aug. 10, which has been on the liturgical calendar for quite a long time. They observed the meteors to fall every August. They put the two together.

At its heart, science is about observing the natural world and understanding it. These Catholic folks observed the natural world. Unlike the astronomers, they did not have preconceived notions about what category of phenomenon the meteors were. Therefore, they achieved a better understanding of this particular part of the natural world ahead of the astronomers.

We can even make a guess at when they did this. When Pope Gregory XIII introduced his reformed calendar in 1582, the calendar shifted by a week and a half. Therefore, prior to 1582, the Perseids were not starting to fall around Aug. 10 (they would have been falling in July). So people discovered the “Tears of St. Lawrence” sometime after 1582, but enough before the 1830s for the “tears” to have become part of local Catholic lore.

Today we understand the August meteors to be particles of debris that are strewn along the orbit of a comet — particles that enter the Earth’s atmosphere and are heated to glowing by their rapid motion through the air and the resulting friction. Earth, circling the sun annually, passes through the cometary debris stream every August, and thus the meteor shower.

The Perseid meteors are indeed an atmospheric phenomenon, and they are indeed fiery falling things. It is just that they have an astronomical origin.

Chris Graney lives in Louisville and is part of the Vatican’s astronomical observatory, which recently launched a new website at www.VaticanObservatory.org.

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