An unnerving video shows just how far down into the murky depths of the ocean the submersible that has become lost whilst on an expedition to the Titanic could be.

Of course, the ocean is incredibly varied, but the deepest parts of it are less explored than the space that surrounds our planet.

There are things down there that we simply have no idea about, because the conditions at the very deepest parts of the ocean are so alien, so deep, so dark, and so inhospitable.

The wreck site of the RMS Titanic - the destination for a submersible owned by exploration company OceanGate - is at one such part of the ocean.

It sits some 12,500 feet beneath the almost-freezing cold North Atlantic, a depth of around 2.4 miles, if you prefer.

It’s also around 600 kilometres from the coast of Newfoundland in Canada, so it’s even more remote than you might think.

YouTube/MetaBall Studios

However, that was the destination for the five-person submersible that set off down there before losing contact with the boat on the surface.

It has been confirmed that the five people on board at the time of the disappearance are OceanGate CEO and founder Stockton Rush, billionaire Hamish Harding, French diver Paul-Henri Nargeolet, Pakistani businessman Shahzada Dawood and his 19-year-old son Suleman.

As it stands, the supply of oxygen is running out and the craft has yet to be located.

The most recent development has been that a Canadian aircraft flying over the Atlantic detected ‘banging’ noises coming from the ocean, as the final 24 hours of oxygen aboard the vessel tick down.

In the video above, you’ll see a graphic illustration of exactly where the submersible could be, and the ocean below it.

The scale is terrifying, and one of the truly disconcerting parts about this whole thing is that the wreck of the Titanic isn’t even at one of the deepest parts.

In fact, the depth that she lies at is around average for the Atlantic Ocean, as well as the Indian Ocean.

YouTube/MetaBall Studios

To get to the very bottom of the ocean you’d have to be in the Pacific Ocean, at the bottom of the Mariana Trench.

That’s the deepest known place on earth, and there’s very little known about what lies down there.

Darkness, and very little else, you’d have to imagine.

Scary though it is, hopefully it illustrates the challenges faced by those tasked with locating the OceanGate sub and rescuing those aboard.

Hopefully they find them very soon, as time is running out.