Fringe Authors Described as a 'Peddler of Popular Mysteries' Turned an Antarctic Sponge Into Aliens

A mysterious 'antenna' photographed on the Antarctic seabed in August 1964 has been repeatedly cited by alien enthusiasts as proof of otherworldly technology lurking in the deep ocean, but marine biologists say the Eltanin image is nothing more exotic than a carnivorous sea sponge.

The photograph was taken by the US research vessel Eltanin, operated for the National Science Foundation after serving five years as a US Navy icebreaker.

Beginning in 1962, the ship became the world's first dedicated Antarctic research vessel, towing cameras and strobe lights over the seabed to capture grainy black-and-white glimpses of one of the planet's least-known environments.

Two years into that mission, on 29 August 1964, while working about 1,000 miles south of Cape Horn, Chile, the camera picked up something no one on board could readily explain.

The now-famous frame showed a solitary structure jutting out of the mud: a thin central stalk with a ring of precisely spaced, straight 'arms' fanning out horizontally, each ending in a neat little sphere. It looked, frankly, engineered.

The New Zealand Herald did not publish the first detailed account until 5 December, headlined 'Puzzle Picture From Sea Bed.' At the time, scientists on the Eltanin were as perplexed as anyone. 'At that depth there is no light, so photosynthesis could not take place and plants could not live,' senior marine biologist Thomas Hopkins told the Herald.

'If it is some strange coral formation, then no one on board has ever heard about it before. I wouldn't like to say the thing is man-made because this brings up the problem of how one would get it there. But it's fairly symmetrical, and the offshoots are all 90 degrees apart. This is why it has been argued over for so long.'

In that uncertainty, a space opened up for more fantastical readings of the image, and others were quick to step into it.

How a Sea Sponge Became 'Alien' Technology

The so-called Eltanin antenna started its second life in the late 1960s, when it was lifted from obscure expedition report to pop-culture curiosity.

A 1968 article in Saga magazine by Brad Steiger as a 'peddler of popular mysteries' reframed the odd-looking structure as something potentially built, not grown. Once that seed was planted, the alien narrative stuck.

Steiger leaned heavily into the unease that accompanies any unexplained image. 'One cannot help becoming a bit uneasy knowing that someone, whether they be space visitors or representatives from some undeclared terrestrial organisation, knows quite a bit more about the measurements and crucial rumblings of our planet than our top scientists do,' he wrote.

His suggestion was careful enough to be deniable, but direct enough to lodge in readers' minds.

The Eltanin photograph migrated into UFO books, conspiracy forums and late-night radio shows, usually stripped of its original context and without the awkward detail that nobody had actually found a physical device on the seafloor.

The word 'antenna' did the heavy lifting: an object with arms, spheres and symmetry, sitting alone in the Antarctic depths, sounded like the perfect piece of alien surveillance hardware.

The problem for that story is that marine biology had effectively solved the puzzle decades before the conspiracy theories took off.

The Real Eltanin 'Antenna' Is a Carnivorous Sponge, Not an Alien Relic

What the Eltanin camera captured is not metal, not a sensor array, and not evidence of alien civilisation. It is a carnivorous sea sponge commonly known as the ping-pong tree sponge, scientifically named Chondrocladia concrescens.

Hopkins was correct to rule out plants and photosynthesis. He was also right that it was not a coral or familiar seaweed. Where the alien narrative goes off the rails is the assumption that 'not a plant and not a coral' must mean 'artificial technology.' In this case, it simply means 'animal.'

The ping pong tree sponge anchors itself in the mud with buried, branching roots, then sends up a long stalk with nodes bearing four to six club-shaped branches. Each of those branches ends in a swelling that, in life, is covered with tiny hooks and fibres used to ensnare passing prey. The whole thing looks uncannily tidy on a monochrome seabed photograph.

Crucially, this was not some unrecorded lifeform materialising out of nowhere in 1964. Swiss-American marine biologist Alexander Agassiz had already described and illustrated the same type of sponge in the late 19th century during an Antarctic expedition aboard the research ship Blake.

He wrote of 'a long stem ending in ramifying roots, sunk deeply into the mud. The stem has nodes with four to six club-like appendages.' That description, and his drawings, match the Eltanin silhouette almost too neatly to ignore.

None of that has stopped the alien claims circulating, of course. Internet retellings often omit the sponge identification altogether, or treat it as a kind of dull 'official line' to be distrusted.

Yet no physical evidence of an artificial device has ever been recovered from the photographed site, and no independent expedition has reported anything remotely resembling an engineered antenna there. There is the image, the speculation, and little else.

If anything, the Eltanin story says less about the deep ocean than it does about us. Faced with a blurry frame from a hostile environment, the choice is between a strange but documented animal and an invisible alien intelligence monitoring Earth's 'crucial rumblings.'

One requires a microscope and a trawl net. The other requires a leap of faith. For those still convinced, nothing is confirmed yet, so every claim about alien hardware on the Antarctic seabed should be taken with a grain of salt. The sponge, on the other hand, is very real.