TRANSCRIPT: The Great Meteor Procession of 1913

On February 9, 1913 an extraordinary and unique phenomenon was observed by multiple witnesses across Canada, the US and the island of Bermuda. Known as the Great Meteor Procession, this event seems to suggest that Earth once had, at least for a time, a second, small natural satellite. Think about that, that would mean that up until 1913 Earth technically had two natural moons.

Over a hundred reports exist of this phenomenon and what they indicate is that between 40 and 60 very slow moving fireballs arranged in groups moving in what appeared to be an identical path crossed the sky over the course of several minutes. This would be unusual for a normal meteorite, those tend to be lone wolves. It would be less unusual for a meteor shower, though those tend to involve dust grains and the apparent size of these fireballs would be more consistent with sizeable meteorites.

Meteor showers also tend to be fairly predictable events. They happen at the same time each year as earth passes through debris field left in the trail of comets that have crossed our orbit at some point in the past. Meteor showers also exhibit something called a radiant, this is a point in the sky where meteors, if you trace them backwards, appear to originate.

Astronomer Clarence Chant determined from the reports that The Great Meteor Procession did not have a radiant, and instead seems to have followed a great circle trajectory. There are thought to be two possible reasons for this. The parent object might have encountered earth before, grazed the atmosphere at a shallow angle and skipped back out into space. This is not unheard of, a rather large fireball was witnessed doing just that over western North America in 1972. Once back in space it might have broken up into pieces setting up for the multiple fire balls observed when it encountered earth again and was drawn in.

The second possibility is that whatever was the source for the meteors was formerly in orbit of earth. Now, bodies in the solar system, including earth, can capture other objects such as asteroids. Quite a few of the smaller moons in the outer solar system are believed to be just that, captured asteroids. They can eventually end up in stable orbits if the conditions are right, or they can orbit for a time in a decaying orbit. The latter may have been what happened here.

But there's another possibility and while it's sort of one of those old, dusty theories within space science that not a lot of people remember it was at least intriguing at the time. Astronomer John O'Keefe proposed that instead the material that made up the fireballs was instead a remnant of a ring system Earth might have had at one time, similar to Saturn.

This ring system would have been produced by the action of lunar volcanos long ago when they were still active, which relates to another theory of O'Keefe's that tektites, a group of natural glasses that show clear evidence of once having flown aerodynamically through the atmosphere, originated on the moon. His main evidence for this was a curious lack of water in tektites, internally they are very dry for something that originated on earth.

The theory was given serious consideration by science at one time. However subsequent studies of tektites have shown that they are most likely generated from earth rock melted during crater-forming asteroid impacts. The evidence for this has accumulated and is now pretty convincing but it doesn't really answer O'Keefe's ring theory.

Might the moon early in its history have sprayed materials far enough out into space to form a planetary ring system around earth? There really isn't much evidence for it unfortunately, other than potentially the Great Meteor Procession. And with that, no associated meteorites were ever found so we may never know the origins of this event. But it's at least fun to imagine planet earth with a second tiny moon, or even a ring long ago in the past. 

Thanks for listening! I am futurist and science fiction author John Michael Godier currently plugging my second channel. It's dedicated to science fiction and the science behind it and in a not-so-creative frenzy one night I named it John Michael Godier II, link in the description below and be sure to check out my books at your favorite online book retailer and subscribe to my channel for regular, in-depth explorations into the interesting, weird and unknown aspects of this amazing universe in which we live. 

TRANSCRIPT: Detecting Alien Stellar Engines

The universe can be a chaotic place where galaxies collide and stars get ejected to wander the intergalactic universe unassociated with their parent galaxy. If this situation were to happen to an inhabited star system, it might not be desirable to be ejected, or likewise if alien astronomers calculated a high likelihood that their star might be eaten by a black hole in a few million years, they might choose to construct a monumental, but hypothetically possible, megastructure that can actually move their star.

Moving a star requires a variant of the Dyson shell concept called a Shkadov drive, or class A stellar engine. It's a surprisingly straightforward idea originally put forth in 1987 by Dr. Leonid Shkadov. The idea is to build an enormous spherical mirror to reflect the radiation pressure of a star in a different direction. This would have the effect of creating thrust and would propel the star in whatever direction the alien race wished it to go. As the star moved, it would carry its planets with it just as the sun does now with our planets as it travels through the galaxy.

The problem with this idea is that the thrust would be very slight and moving a sun-like star any large distance would take millions of years so it's difficult to envision that too many of these things get built out there in the universe. But it is possible, and there is room for other scenarios where a civilization might build such a thing to move a star just a small distance if that's what they happened to need. Or, if you have a civilization that's billions of years old and very forward thinking, they might not blink an eye at projects that take millions of years to complete.

So the question is, if there are civilizations building Shkadov drives, would we be able to detect them? Just such a method was put forth in a paper, link in the description below, by Dr. Duncan Forgan of the University of Edinburgh in 2013. It's worth noting that one of the main ways we detect exoplanets is by looking at the light curves of their stars as they pass in front of it and block light.

In other words, the data needed to detect a Shkadov drive is being taken anyway in the course of finding exoplanets and studying stars. It's more a matter of someone noticing something odd in those light curves, which is how Boyajian's star was identified. Now there are issues that Forgan points out, determining if a light curve indeed indicates the presence of a Shkadov drive could be complicated by other things in the light curve, such as the presence sun spots, so much observation would be needed to confirm such a thing.

Forgan also points out that while the chances of finding a star with a Shkadov thruster are exceedingly low but with all the data that's available scientists looking for other things should be aware of strange signatures in light curves that could indicate the presence of a Shkadov drive and anyone wishing to specifically look for them could do so at low cost from already available data.

So add one more way that we might detect an alien civilization independently of radio astronomy. I think this is one of the more unlikely scenarios, I can't imagine this type of megastructure would be very common, but astronomers see all sorts of interesting things in light curves so some day in the future who knows?

Thanks for listening! I am futurist and science fiction author John Michael Godier and if you'd like to help support the channel check out my Patreon page, link in the description below, or check out my books at your favorite online book retailer and subscribe to my channel for regular, in-depth explorations into the interesting, weird and unknown aspects of this amazing universe in which we live.