What is this pulsating dot visible in day sky Denmark?

[Mendel]

. I looked up some bird strike reports and they do sound like a serious and increasing problem.

I haven't seen the numbers, but it doesn't feel like it's increasing.

Drones are increasingly becoming more of an aerial threat,

Drone operators generally do a fairly good job of keeping their precious cargo away from aircraft. The only proven incident I know of involved a drone denting a firefighting aircraft. (Not every "drone threat" is caused by drones, we have threads on that, too.)

I'm more concerned about whet'll happen when some Amazon drone weighing half a ton encounters a flock of birds over mid-town. That'll test the redundancy designed into the system. The fact that two Amazon drones crashed into the same crane recently does not bode well.

 

[Carling 4737]

The Amazon drone scenario does sound a bit worrying. I wondered about other things colliding with planes and found a recent report on a possible meteorite strike on a plane. The article also discusses a weather balloon or space debris as the culprit, but conclusive proof seems hard to come by:

https://www.theweathernetwork.com/e...ery-did-a-meteorite-strike-this-passenger-jet

A meteorite strike was the subject of speculation in a Scientific American article back in 1997, in regards to TWA Flight 800:

https://www.scientificamerican.com/article/is-it-possible-that-a-met/

 

[Mendel]

I wondered about other things colliding with planes and found a recent report on a possible meteorite strike on a plane. The article also discusses a weather balloon or space debris as the culprit, but conclusive proof seems hard to come by:

https://www.theweathernetwork.com/e...ery-did-a-meteorite-strike-this-passenger-jet

That article is out of date, it was confirmed to be a radiosonde (weather balloon) with a sand bag ballast.
See https://www.metabunk.org/threads/un...d-windshield-weather-balloon-collision.14502/

How did you find that link?

 

[Mendel]

A meteorite strike was the subject of speculation in a Scientific American article back in 1997, in regards to TWA Flight 800:

https://www.scientificamerican.com/article/is-it-possible-that-a-met/

But the appropriate question to ask in this situation is, 'What are the odds, throughout the history of commercial aviation, of a meteor striking an airplane such that it would penetrate the plane's fuel tanks?' We considered the number of planes in the world, the fraction of the time they spend in the air, their size, and the number of meteors entering the atmosphere per day, etc. Based on those numbers, we derived a probability of about 10 percent.

And in fact TWA 800 was not hit by a meteor.

Article:

The four-year NTSB investigation concluded with the approval of the Aircraft Accident Report on August 23, 2000, ending the most extensive, complex, and costly air disaster investigation in U.S. history up to that time. The report's conclusion was that the probable cause of the accident was the explosion of flammable fuel vapors in the center fuel tank. Although it could not be determined with certainty, the likely ignition source was a short circuit.

Source: https://en.wikipedia.org/wiki/TWA_Flight_800

Edit:
From the NTSB report, via https://www.ntsb.gov/investigations/Pages/DCA96MA070.aspx :

1.16.6.11 Meteorite Strike Information
During the evenings after the TWA flight 800 accident, many meteorites were observed in the northeastern United States. Therefore, the Safety Board considered the possibility that TWA flight 800 was struck by a meteorite, which then caused the CWT explosion. The Board consulted an expert in the study of meteorites, a professor from the University of Pittsburgh's Department of Geology and Planetary Science, to evaluate the possibility of a meteorite hitting an airplane. According to the professor's testimony, knowing the frequency with which meteorites have struck cars and dwellings over the past several decades, and based on a comparison of estimates of (1) the area of the earth's surface represented by cars and dwellings with (2) the area of the earth's surface represented by airplanes in the air at any given time, he calculated that a meteorite could be expected to strike an aircraft once every 59,000 to 77,000 years.

The full analysis "Estimated Frequency of a Meteorite Striking an Aircraft" is in the public docket, at https://data.ntsb.gov/Docket/Document/docBLOB?ID=40058953&FileExtension=.PDF&FileName=Estimated Frequency of a Meteorite Striking an Aircraft-Master.PDF
It is dated March 2, 1998, 8 months after the SA article came out.

 

[Carling 4737]

It's good to know that proper investigation wins out in the end. Like the article says, low probability. Interesting that they considered a meteorite initially. So it seems weather balloons can pose a (albeit low) threat to planes - that poor pilot's arm looked messy. I saw the article referenced in a recent copy of, er, Fortean Times (I know, I know). and decided to have a look online for it.

 

[Mendel]

So it seems weather balloons can pose a (albeit low) threat to planes - that poor pilot's arm looked messy.

well, yes—I linked my Metabunk thread on that incident back in post #37, where I wrote the risk is low.
(Most radiosondes do not carry ballast, and this company promised to take greater care to avoid aircraft in the future.)

 

[Carling 4737]

"well, yes—I linked my Metabunk thread on that incident back in post #37, where I wrote the risk is low.
(Most radiosondes do not carry ballast, and this company promised to take greater care to avoid aircraft in the future.)"

This is the first forum I've ever joined so I'm still learning about how it all works, and how to find topics already touched upon, etc, so thanks for pointing that out. It's a learning curve, for sure. Sounds like we're in complete agreement!

 

[Mendel]

This is the first forum I've ever joined so I'm still learning about how it all works, and how to find topics already touched upon, etc, so thanks for pointing that out. It's a learning curve, for sure. Sounds like we're in complete agreement!

You're doing great!
The nice thing about forums is that they've got a memory. You read my first reply on balloons back then and came away with "don't worry about balloons" in your mind, and now you saw the pictures and are worried a bit, but you can go back and re-read what I actually wrote, and it included this incident already. And that's just how our minds work!
When I find myself discussing with people, I often do read back, so I don't lose track of what we're talking about, and I try to find the actual quotes of what was said. It's helped me more than once!

In that vein, on this forum, when I mark someone's text, I get a popup option to 'quote' or 'reply'. The first option puts it away, to be used as 'insert quotes' in the editor, and the second starts a reply right away. You can also use the links at the bottom of each post to quote or reply, and it often helps to edit that down a bit and cut what's not relevant to the reply if it's long.

The second tip is to learn to use the site search in the upper right-hand corner if you want to get the best out of metabunk. And I say "learn", it's because it's a bit of an art. (And it helps to remember what you're looking for, too! )

Cheers!