A new study has revealed that Earth actually has eight continents.

For millennia, mankind has lived knowing that the Earth is divided in seven continents -- Africa, Asia, Antarctica, Australia, Europe, North America and South America. But there's actually another piece of the puzzle, and it's called Zealandia.

According to the paper published in The Geological Society of America, New Zealand is actually sitting on this massive continent that has been hiding in plain sight all these years.

Zealandia, which measures five million square kilometers, broke away from Australia and sank about 60 to 85 million years ago. At present, it is 94 percent submerged in the southwest Pacific. The paper added that it broke away from Australia and sank about 60 to 85 million years ago.

As reported by CNN, currently, New Zealand and New Caledonia are grouped with Australia. But over the last two decades, geologists have been looking for a proof that it should actually be considered a separate continent. Geophysicist Bruce Luyendyk coined the term Zealandia in 1995.

What made the researchers finally nail the proof that Zealandia is a continent?

As mentioned by the Sydney Morning Herald, there are four criteria that must be met to be classified as a continent. Among those, the most important is that it should be highly elevated as compared to the ocean crust.

To realize this, the researchers used satellite technology. Gravity maps of the sea floor have revealed that Zealandia is a large unified area. While most of the part of Zealandia is submerged, its area is massive, intact and well-defined. Above all, it has a crust that's thicker than the regular ocean floor.

In essence, Zealandia not only encompasses New Zealand, but as well as New Caledonia, Norfolk Island, the Lord Howe Island group and Elizabeth and Middleton reefs.

"The significance of the recent paper is that it is the first peer reviewed published paper properly defining and proposing Zealandia. As such we hope it will be the 'go to' reference on the subject," Nick Mortimer, lead author of the study, told Fairfax Media.

Meanwhile, there is currently no scientific body that formally recognizes continents. The only thing that would make it be declared as such is if a scientific body is formed or if most of the scientific community agrees to it.