How do you like my New & Improved title style? Is it click-baity (or is it baitey) enough? I was also thinking of Attack From Space Nearly Downs Aircraft.
The NY Post went with “United Airlines pilot injured after mystery object smashes windshield at 36,000 feet“.
Mysterious object isn’t nearly as exciting as UFO. But it was a UFO.
Something unknown, flying, hit United 1093 on its way from Denver to LA at 36,000 feet, which is almost 7 miles straight up. Birds aren’t usually roaming around up there, and a spokesman for Superman couldn’t be reached. So the surmise is a pebble from space, a cheeseboard tossed out the window of a rival Jetblue flight, or debris breaking free from all the junk we’ve hoisted into low earth orbit hit United 1093.
Here’s a picture of the plane. Six inches to the left and whatever it was would have gone right through the window and this report would not be as light-hearted. As it was the glass cut up the arm of the pilot. It would have been moving pretty fast.
What are the chances?
As I have been trying to convey, all probability questions have two parts. The thing of interest, and the evidence one assumes is probative, and that both sides of this have all the baggage of implicit and tacit assumptions of language. We have to be careful.
That this plane was hit at that altitude, presumably from something from space, is 1. It happened, therefore the probability is certain. But what about your plane, the plane you’ll be on as you pop down from Detroit to the balmier weather of Tampa in January?
Turns out the FAA has made calculations along these lines, which certainly saves us effort. Some obscure law requires them to write reports on such matters and deliver them to Congress. Incidentally, a huge number of laws make similar requirements, which is why the bureaucracy is always expanding. All those reports to write have to be written, and reported on, by somebody.
In the latest FAA report, we find this:
By 2035, if the expected large constellation [groups of satellites dedicated to a joint purpose] growth is realized and debris from Starlink satellites survive reentry, the total number of hazardous fragments surviving reentries each year is expected to reach 28,000, and the casualty expectation, the number of individuals on the ground predicted to be injured or killed by debris surviving the reentries of satellites being disposed from these constellations, would be 0.6 per year, which means that one person on the planet would be expected to be injured or killed every two years.
As the picture above proves, a tinfoil hat won’t be sufficient to ensure you’re not one of these 0.6 people. Perhaps Teslas come with hardened roofs.
They also say:
Some debris fragments would also be a hazard to people in aircraft. Projecting 2019 global air traffic to 2035 and assuming that a fragment that would injure or kill a person on the ground also would be capable of fatally damaging an aircraft, the probability of an aircraft downing accident (defined in the Aerospace report as a collision with an aircraft downing object) in 2035 would be 0.0007 per year.
Note carefully they say downing, and fatally damaging. Neither of which, thank God, is true of United 1093. They were only pinged. They don’t give chances for pinging. Plus, that accident could have been a wannabe bolide (i.e. small rock or pebble from space) and not satellite debris. Finally, that 0.0007 seems to a cumulative number of all aircraft over a year, and not your own single flight.
They say “Despite guidelines recommending purposeful reentry, large space objects reenter the Earth’s atmosphere roughly once a week.” These are unplanned reentries. NASA tracks more than 25,000 larger than 10 cm (about 4 inches in civilized units) of these objects. They have models on the reentry of debris, but those are beyond us today.
The FAA warns: “In May 2021, a Chinese rocket body reentered through random atmospheric reentry…It measured 98 feet long and 16.5 feet wide, and it weighed 21 metric tons. Fortunately, the debris landed near the Maldives, and no injuries were reported.” None reported.
Calculating reentry is far from easy, which increases uncertainty. The FAA says “reentry time can be off by ten percent of the orbital time remaining…Given that an object in LEO [low earth orbit] circles the globe in just 90 minutes at over 27,000 kilometers per hour, at 10 hours before reentry, the likely reentry area is 27,000 kilometers long. Even 60 minutes prior to reentry, the potential area over which debris may fall is still over 2,000 kilometers long.”
The latest numbers reported in 2021 say “there was about a seven percent chance of at least one person on the planet being seriously injured or killed by the debris from space vehicles”. That 7%, to me, is a large chance. One which should increase year on year, since the debris only increases.
Accepting those numbers, and letting the chance be 0.07 per year, here’s the cumulative chance for at least one creaming by year for each year out to 2036 (using the inclusion-exclusion formula we used in the Large Rocks From Space post):
It’s 50-50 (conditional on all our evidence) by 2036 somebody on the ground is attacked by debris from space. This is for people anywhere on the planet, and not just in San Francisco, even though residents there are most deserving.
Point is that it’s going to happen eventually, if all these assumptions are correct. And when it does, boy will the conspiracy theories fly. Who is going to believe that Old Joe, walking along minding his own business, is suddenly pulverized–for no reason! And with no suspects in sight. Even if an object from space is acknowledged, the suspicion that, say, this was a test of a new weapons program won’t be resisted.
The numbers are more difficult to calculate for planes, because there are fewer planes operating over more area, and if one is downed there are many more dead in the incident. FAA says “The combined impact, with fewer aircraft with many people aboard, results in the 0.1 percent” per annum. They seem to mean individual death and not aircraft crashing. Which is confusing.
The FAA goes on to say that the base 0.001 for 2021 is not constant and rises to 0.0084 by 2035. So, supposing it’s aircraft downing, we get this similar cumulative chart by year:
That’s a 5% chance or so by 2036, conditional on lots of assumptions, some of them dubious, that a plane succumbs to a UFO. Still, it doesn’t seem that large to me, not given United 1093 missed becoming our first incident by mere inches.
We still haven’t reached the chance for a single flight. But we can back it out, at least to an order of magnitude. First, they FAA provides neat charts like this, which show population and aircraft density by latitude. Useful for more detailed calculations, but beyond what we’ll need. I thought it too interesting to pass up.
Somebody can check which cities are around 40 North, which are places the aircraft hit by debris is most likely to land unexpectedly.
Since the FAA uses the language “at least one”, this implies they (or the firm they employed) used a well known equation. Which is 1 minus the chance no plane gets it, which itself uses whatever number ‘p’ an individual plane is whacked, and the number of flights ‘n’ per year. Twitter’s search engine said 36.4 million flights worldwide for 2024. I have no idea if that’s right, but it seems plausible. If you have another number, you can pop it into this equation for ‘n’:
$$1 – (1-p)^n = 0.001$$
and solve for p. That is
$$p = 1-\exp^{\frac{\ln(0.999)}{n}}.$$
And for n = 36.4 million, the chance of an individual plane being drilled is about 1 in 100 billion. Given what we know of commercial airline travel, it’s a lot more likely your flight will be downed by something like pilot suicide or something mechanical going kerblooie.
Now there are something like 1 to 5 big crashes a year of planes carrying greater than 30, and out of the 36.4 million flights, call it 1 in ten million. Not of debris, but of other things.
Whatever that final number is, it doesn’t seem to stop people from boarding planes, so the addition (more of less add that 1 in 100 billion to the 1 in ten million) of the Attack From Space shouldn’t change behavior much, or at all.
Nevertheless, perception is very often stronger than fact, so it depends on how these things are viewed.
Subscribe or donate to support this site and its wholly independent host using credit card click here. Or use PayPal. Or use the paid subscription at Substack. Cash App: \$WilliamMBriggs. For Zelle, use my email: matt@wmbriggs.com, and please include yours so I know who to thank. BUY ME A COFFEE.
Discover more from William M. Briggs
Subscribe to get the latest posts sent to your email.
