Antarctica’s “gateway to the underworld”: what the science actually reveals

For the past few weeks, a story has ricocheted around the internet about Antarctica: a supposed “gateway to the underworld” seen from space and tied to a Cold War secret. The reality is less showy - but genuinely more compelling. Newly digitised aerial photographs from the 1950s, combined with today’s ice-penetrating radar and thermal mapping, are exposing a patchwork of vast voids, warmer zones and concealed water routes beneath the ice. It’s unsettling to picture. It’s also important research.

What sparked the rumours

The rumour mill was fuelled by a familiar recipe: blurry imagery, partially released documents and satellite shadows that could be read more than one way. A set of mid-20th-century reconnaissance photos, previously tucked away in defence archives, resurfaced thanks to digitisation work by polar research institutes. In those frames, commentators picked out dark, oval shapes on coastal ice cliffs, alongside unusual heat signatures drifting downwind of Mount Erebus - Antarctica’s well-known active volcano.

With a little online embellishment, one label spread quickly: “gateway to the underworld”. The evidence, however, points to a grounded explanation. The apparent openings and the warmer plumes are consistent with subglacial caves, basal cavities and vented steam - not a portal, but still a real hidden world inside the ice.

Cold War-era imagery and modern radar surveys agree on a single point: Antarctica contains warm, hollow spaces beneath kilometres of ice.

Antarctica: what new mapping actually shows

Researchers are now weaving together three main lines of data. First comes historic aerial photography, which helps pinpoint features that persist over time. Second are satellite-based thermal measurements and radar interferometry, used to infer heat and movement through the ice. Third is low-frequency ice radar deployed by aircraft and field teams, which can outline cavities, channels and bedrock beneath the ice sheet.

Together, these approaches are sharpening our view of a huge, dynamic landscape under the ice. Water moves. Caverns exchange air and heat. The ice itself bends with the tides. None of it is supernatural - and all of it is consequential.

Subglacial lakes and hidden rivers

Beneath Antarctica sit hundreds of subglacial lakes: sealed under ice yet liquid below. High pressure and geothermal warmth stop them freezing solid. Radar observations show these lakes can fill and then drain through tunnel-like pathways, sometimes across distances of tens of kilometres. Those concealed rivers can feed coastal ice shelves and excavate voids the size of football stadiums beneath rapidly flowing glaciers.

Fresh work beneath Thwaites and Pine Island glaciers has identified towering cavities at the grounding lines, where the ice transitions to the ocean. These spaces can accelerate melting by guiding warmer seawater towards the underside of the ice. In cross-section they resemble open mouths - visually striking, and significant enough to alter sea-level projections.

Volcanic heat and ice caves

Antarctica is not only ice and silence; it also has heat stored below. Around the Mount Erebus system, fumaroles vent steam that can hollow the ice into caves where air temperatures rise above freezing. Some chambers glow with light filtered through thin, blue ice roofs; others are pitch-dark, warmed from beneath. Investigations of these caves have detected microbial DNA and evidence of life powered by chemical energy rather than sunlight.

Outside Erebus, West Antarctica is dotted with low-level geothermal hotspots. Each one can shave millimetres to centimetres per year from the base of the ice sheet. Over decades, that steady heat can carve out chambers and channels - the “rooms” now turning up in radar cross-sections and thermal maps.

No, not a mythical underworld. Yes, a warm, hollow landscape hidden inside the ice, shaped by heat, pressure and time.

So - was a gateway found?

In plain terms: no portal, and no fantasy city. The much-shared “entrance” appears to be a large sea-ice doline and a lava-tube opening near Erebus - both genuine, both natural. In other places, coastal ice cliffs show arch-like recesses where meltwater and wave action erode the shelf. Seen in low-angle sunlight, these shapes can look cavernous from orbit.

The bigger story, though, is not about one dramatic opening. Over roughly the past 70 years, evidence has steadily accumulated for an active under-ice system most people never witness: caves that vent steam, lakes that pulse as they fill and drain, and rivers that can run uphill when pressured. That is the real secret - sitting in plain sight within the ice sheet.

Why this matters right now

Heat and water beneath the ice largely dictate how quickly glaciers slide and how fast they thin. Cavities at the grounding line can act as gateways for warm ocean water to reach and erode ice shelves. As shelves weaken, inland ice can accelerate towards the sea. That chain reaction pushes up sea-level rise projections for this century. It also affects marine ecosystems on the continental shelf, where fresh meltwater mixes with seawater.

For biologists, geothermal caves provide a natural testbed for life in cold, dim environments - relevant to worlds such as Europa or Enceladus, icy moons thought to have warmer interiors. Methods refined in Antarctica - sterile drilling, contamination-controlled sampling and autonomous rovers - are expected to shape future missions beyond Earth.

What the evidence points to

• Large subglacial cavities at major glaciers, particularly where ice meets the ocean.
• Geothermal hotspots producing warm, ventilated ice caves near volcanic centres.
• Active drainage systems shifting water between subglacial lakes.
• Seasonal “breathing” of caves and crevasses as wind and pressure move air in and out.
• No confirmed human-built structures or “portals”, despite viral claims.

Key sites and why they draw attention

Site	Feature	Why it matters
Mount Erebus area	Steam-formed ice caves and possible lava tubes	Warm pockets support distinctive microbes; cave mouths can look like doorways in satellite imagery
Thwaites Glacier	Grounding-line cavities	Speeds melting and ice flow; crucial for sea-level projections
Lake Vostok region	Gigantic subglacial lake	A window on isolated ecosystems; informs sterile access methods
Pine Island Glacier	Sub-ice channels to the ocean	Channels funnel warm water and drive ice-shelf retreat

How researchers will check the claims

Field teams are preparing targeted campaigns for the next austral summers. The plan is to work quickly, lightly and cautiously, keeping both contamination risks and costs down.

Tools heading south

• Low-frequency radar sleds to map caves and channels at higher resolution.
• Autonomous underwater vehicles to inspect grounding-line cavities from below.
• Thermal drones to follow vents and steam plumes around Erebus.
• Clean hot-water drills to reach lakes without introducing microbes.
• Seismic nodes to detect the “breathing” of voids during tides and storms.

Expect fewer sweeping claims and more meticulous maps. The forms beneath the ice will speak for themselves.

What this means for travellers and the curious

Tour vessels will not be visiting these locations. Many of the features lie on dangerous ice or beside heavily crevassed shelves. Even research teams proceed carefully, typically starting with remote instruments rather than approaching on foot. Online images can also overstate the scale of openings through tight cropping or dramatic lighting. If a photo looks like a film set, it probably is.

Extra context you can use

“Subglacial hydrology” is the key term here. Water under ice moves under pressure, which means it can flow uphill along the bed. That counterintuitive behaviour helps explain abrupt lake drainages and why glaciers can surge when water lubricates their base. A straightforward demonstration uses a sloped tray, a sponge and a syringe: compress the sponge beneath a flat plate and the water jets out at the thinnest edge. Glaciers follow a similar principle on a much larger scale.

There is also a clear trade-off between opportunity and risk. Geothermal caves may harbour unfamiliar microbes with enzymes useful in medicine or industry - yet those same caves could be spoiled by contamination from a single careless bootprint. Current best practice therefore prioritises sealed sampling lines, sterilised equipment and minimal time on site. The prize is substantial: improved sea-level forecasting, cleaner techniques for detecting life beyond Earth, and a realistic view of Antarctica’s internal systems - without any need for myths.