The Spell of Ai

addendum to The Great Fireball

At the start of each day, give a little prayer of mercy, and at the end of each day, give a little prayer of thanks.

Photo by NASA on Unsplash

It’s the End of the World as We Know It
it’s the end of the world as we know it…
That’s great, it starts with an earthquake
Birds and snakes, and aeroplanes
And Lenny Bruce is not afraid

it’s the end of the world as we know it…and I’m ok
R.E.M., 1987

Research appearing in the previous post left some questions unanswered:

• Why did our experience differ from the 1968 Griffin paper?

• Why did we see a low and slow-moving object when the data recorded the opposite?

• What was the sound we heard?

Earth-grazing asteroids (aka, TCOs or temporarily captured orbiters)

The earliest viable scientific research into TCOs was 1972, four years after 1968 and six years after the fireball of 1966.
Even still, although several events of the past few hundred years are now acknowledged as Earth-grazing asteroids, the fireball of 1966 is not included; there simply is not enough evidence to satisfy astrophysicists who would take first person accounts with a grain of salt (only two photographs).

So…

Excerpts from: On the capture of small stony asteroids into the Earth’s orbit by atmospheric grazing
Shujuan Geng, Binghong Zhou and Mingtao Li: Royal Astronomical Society, Volume 507, Issue 3, November 2021, Pages 4661-4668 (taken from Oxford Academic)

From the Abstract:

An Earth-grazing asteroid can be captured into a gravitational orbit around the Earth during its transitory atmospheric journey…we subdivide the captured and direct impact modes into five - escaping, captured impact with and without fragmentation, and direct impact with and without fragmentation.

We then investigate the conditions of those various impact modes of shallow-angle impacts of small stony asteroids no larger than 100 m in diameter (what?! that’s small?!).

A captured asteroid can enter the atmosphere many times, (!) highlighting itself by a series of explosive phenomena due to the shock wave (!) during every passage.

The long path before its final hit…increases the difficulty of predicting the exact airburst position or landing site.

From the introduction:

Asteroids can bring dangerous hazards…(damn!) from wiping out three-quarters of species 66 Myr ago, known as K-Pg extinction…, to causing over 1500 destroyed architectures and more than 1000 injured people in Chelyabinsk, 2013.

Comparatively speaking, (?) intermediate-sized asteroids (by this we should take it to mean slightly smaller than a skyscraper?) can reach the ground without fragmentation or break up halfway. However, for an object that enters at a shallow angle, also called grazing, things get even more fascinating. (oh, man…)

A grazing asteroid primarily follows three impact modes - besides impacting directly, the object may also escape away into space after a short close journey to the Earth, or more dramatically, get captured into a bound orbit around the Earth during its atmospheric passage. (and re-enter)

Nevertheless, captured impact events are challenging to identify…deserves further study…Tunguska cosmic body might be an iron asteroid grazing the Earth and escaping back into space. (flattened 830 sq mi of forest in Eastern Siberia without leaving a crater - wiki)

So, there you have it:
What we two boys experienced on April 25, 1966, was a grazing asteroid of intermediate size (between 1 m and 100 m in size) moments after its entry; what we heard and felt was its shock wave as it passed overhead during a very close flyby; it was calculated at 66.6 km above sea-level over Mass. based on photographic evidence as it was gaining altitude attempting to escape Earth’s gravitational pull!
The object was never found.

Seems my memory is validated. And if that’s not enough to jiggle the nerves just a bit, consider this: it’s calculated there is a cloud of TCOs orbiting Earth at any given moment.

When the story first appeared right here in S&UP, my summary went: “would not have been more surprised if the Mesiah had dropped down from the heavens, it would only have meant a different future…a cycloptic mega-fauna from space”.

We stand behind that - a space cow - come to graze on planet Earth.

Photo by Wolfgang Hasselmann on Unsplash