Nanook
Paranormal Novice
I don't know that there aren't extraterrestrial craft that are black and triangular, but I do know the US Air National Guard has black triangular craft with three plasma torches in the corners and has been flying them since at least 1978. These are nuclear powered craft with a nuclear fission reactor similar to the reactors in nuclear submarines, and their propulsion is similar to magneto-hydrodynamic propulsion in submarines except that since air isn't normally a conductor, plasma torches are used to make it conductive so that it can be moved with a magnetic field which is generated by superconductive magnets on board.
These were originally designed to monitor Soviet launches in case of a nuclear strike. They needed a craft that has essentially infinite hover time but could get below the clouds if necessary.
They have an array of infrared sensors on the underside, originally for the purpose of detecting rocket launches, especially nuclear missile launches, but later it was discovered that marijuana was particularly bright in the infrared so they used them later to spot marijuana in national forests.
I know this because I knew someone in the Air National Guard that worked on the avionics on these things. They are kept secret because the public might be displeased knowing nuclear reactors are being flown over their heads.
However, similar craft are often reported to be much larger than these, often three or four football fields worth. The problem with these reports is that you have to know how far away something is to know how big it is. Since these things are nearly silent save for some hissing noises given off by the plasma torches, they can be quite low to the ground without someone realizing it, and thus seem larger than they are.
I'm not saying it's impossible that an extraterrestrial craft would be designed by aliens for interstellar travel that has the exact same physical structure as a secret military craft but I think it's unlikely.
These were originally designed to monitor Soviet launches in case of a nuclear strike. They needed a craft that has essentially infinite hover time but could get below the clouds if necessary.
They have an array of infrared sensors on the underside, originally for the purpose of detecting rocket launches, especially nuclear missile launches, but later it was discovered that marijuana was particularly bright in the infrared so they used them later to spot marijuana in national forests.
I know this because I knew someone in the Air National Guard that worked on the avionics on these things. They are kept secret because the public might be displeased knowing nuclear reactors are being flown over their heads.
However, similar craft are often reported to be much larger than these, often three or four football fields worth. The problem with these reports is that you have to know how far away something is to know how big it is. Since these things are nearly silent save for some hissing noises given off by the plasma torches, they can be quite low to the ground without someone realizing it, and thus seem larger than they are.
I'm not saying it's impossible that an extraterrestrial craft would be designed by aliens for interstellar travel that has the exact same physical structure as a secret military craft but I think it's unlikely.