The article was a bit lacking. How do they know that it was a 500 pound bomb from WW2? Is it the shrapnel or is there a different way to determine it?
Yes, someone could have snuck into an airport and buried a bomb underneath the runway, then cleaned up the digging operation so as to not be noticed, but horses, not zebras.
My question was more of, how do they determine this sort of thing or is it just an assumption because it is the most likely scenario?
We are still finding unexploded artillery shells from the first world war in France. Germans are still finding bombs in cities.
The chemicals in the fuses mix and become unstable over time. The explosives don’t degrade as much.
If you wanted further verification, the bomb casing leaves fragments and explosives leave residue.
For it NOT to be a WW2 bomb would mean somebody sneaking in another bomb and paving it under the runway without being noticed.
It could've also been intentionally buried there by bored soldiers, or placed there by airport maintenance people as a prank, or ended up there due to a freak teleporter accident. Maybe it was even put there by Godzilla. Maybe the Infinite Improbability Drive spontaneously materialized it, together with a bowl of petunias.
If you find a bomb in an area which is known to have been bombed, without any evidence to the contrary it is pretty safe to assume it's there due to the bombing.
I don't think they did any exhaustive research. They didn't have to.
You would be able to look at the crater and see sizable pieces of a military air-dropped bomb. Normal bombs don't disintegrate. If they send it to a lab they can tell what explosive was used in it, which will roughly tell you when it was manufactured. (Assuming they don't find a serial number.)
That by itself is hardly conclusive, but that completely changes when you find identical unexploded bombs buried in the same area.
It would be rather odd if somebody came along later and put the same kind of bomb used in WWII in the ground. When the bomb got there isn't that important.
Cool. Now, how did you figure that out? Did someone analyze the shrapnel and conclusively date it to allied bombing campaigns in WWII, or is that what a source close to the events said, or did the reporter just... look at the picture and shoot from the hip? Any of these is an acceptable answer, so long as readers know which one it is.
Let me repeat that, hundred-year-old shells are still underground, intact, and the explosives in them are just as powerful as when they were manufactured.
Chemicals in fuse can slowly combine until they detonate.
The odds of someone planting more explosives in a field potentially containing a dozen WWII bombs from multiple attacks are remote.
So basically you're asking for forensic evidence to prove that this bomb wasn't the result of time-travelers or teleporters or something equally fantastical. It's a ridiculous question. Of course it's an unexploded WWII bomb, what the hell else would it be?
There is a buch of forensic methods around this.
The WWII explanation is much more plausible. It happens at Schiphol too that they find them (luckily not by them exploding randomly but usually during construction efforts)