When did humanity reach its lowest point?

The lowest point on land is in Antarctica

What is under the still thick layer of ice on the continent of Antarctica? Scientists created a new map and discovered amazing canyons in the process.

The Mariana Trench is the lowest point on earth. The valley floor of the gorge lies around 11,000 meters deep in the Pacific Ocean - surrounded by the darkness of the deep sea. But even in the dry - on land - there are points that - possibly semantically confusing - are below sea level. The region around the Dead Sea between Israel and Jordan is considered to be the deepest point on earth that is not covered by water - about 415 meters below sea level. But researchers at a university in the USA have now discovered trenches of unimaginable proportions under the thick ice of the Antarctic.

If one were to imagine snow and ice without, there would be a canyon under the Denman Glacier, the lowest point of which is about 3.5 kilometers below sea level. This is what scientists from the University of California discovered, who studied the topography of the Antarctic continent and who used new methods to re-measure the land under the ice. The findings of their newly created map called "BedMachine Antarctica" were published in the "Nature Geoscience" journal magazine.

The new measurements show previously unknown valleys and rifts on the continent. It is not pure curiosity that drives researchers. The topography under the ice plays a key role in how global warming glacier melting will affect sea levels. Deep ravines would slow down the melting, gentle slopes would rather accelerate it. "This is without a doubt the most accurate picture yet of what lies under the Antarctic ice sheet," said Mathieu Morlighem of the BBC, who worked on the project for six years.

Radars have surveyed Antarctica for decades. Microwave pulses were sent through the ice to reveal the topography below. But many regions remained unexplored in detail. Findings from gravity field measurements and seismological data have now also flowed into the new map. The gorge under Denman Glacier is about so deep and narrow that "the walls of the valley create side echoes that make it impossible to distinguish the reflection from the actual glacier bed," Morlighem told BBC News. The new methods have now brought clarity.

Whether the deep valley under the Denman Glacier can now be considered the lowest point on land is still being discussed in science. After all, snow and ice are also water. If the ice sheet at the South Pole were to melt completely, one would not be able to walk through the valley without dry feet, but would have to dive - just like in the Mariana Trench.

>> The article in the Nature Geoscience Journal

>> The report on BBC

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