The Mysterious Eltanin Antenna

On August 29, 1964, the USNS Eltanin was surveying the sea floor off Cape Horn when the crew photographed a strange object 12,808 feet down that has since caused much controversy. Is it a common but strange looking organism? Or is it, as some believe, submerged alien technology?

The peculiar, antenna-like object superficially resembles a number of jacks (as in the game) stacked atop one another into a thin tower with spokes radiating from the main column, each ending in a round node.

Some, like paranormal authors Brad Steiger and Bruce Cathie, believe the "antenna" is an alien artifact that is part of a vast network of extraterrestrial communication.

Others believe there is a simple biological explanation.

Many have noted its resemblance to the strange carnivorous sponge known as Chondrocladia concrescens.

While the antenna appears far more regular and rigid than the more organic looking sponge images I've seen, I suppose there are probably variations within the species.

For instance a famous illustration by Alexander Agassiz' 1888 tome Three Cruises of the United States Coast and Geodetic Survey Steamer "Blake" shows a drawing of a rather limp specimen that was likely pulled from the sea; whereas, a more modern full color still from an underwater camera shows something that more closely resembles the antenna, albeit with more branches and nodules in a less regimented arrangement.

To make things more complicated, I cannot find any references to the size of the antenna, nor is there anything to give the anomalous image a sense of scale. Is it 10 inches? 10 feet? 100 feet?

And finding anything about Cladorhiza concrescens online that doesn't reference the Eltanin Antenna isn't easy. So, I can't get a sense of how large those sponges grow either.

Ockham's razor compels the logical mind to accept that the most likely explanation is that the antenna is simply a peculiar sea sponge. Still, I feel there are a few questions not satisfactorily answered. I suppose that's why the mystery endures to this day for some.