The secrets of the ice are harder to keep.
Scientists have found a lake of liquid water beneath the ice of the East Antarctic Ice Sheet.
The Lake Snow Eagle is believed to hold information about the evolution of the ice sheet from its very earliest formation.
Don Blankenship of The University of Texas says that the lake is likely to have a record of the entire history of the East Antarctic Ice Sheet, its initiation over 34 million years ago, as well as its growth and evolution across glacial cycles since then.
Our observations suggest that the ice sheet changed a lot about 10,000 years ago, although we have no idea why.
East Antarctica is not completely frozen. Subglacial lakes are hidden beneath the ice that covers the continent.
There are a number of factors at play. The ice sheet's mass lowers the freezing point of water beneath it.
Rocks below provide a source of gentle heating, while the ice sheet provides insulation against the cold air. If the water is briny, saturated with salts, it can lower the freezing point further.
Ice-penetrating radar can be used to detect subglacial lakes. Scientists can study what's below the ice by comparing the transmitted signal with the returned signal from the radar.
A radar signal that bounces back through liquid water is more reflective than other media.
Satellite images show a large depression in the ice sheet of Lake Snow Eagle.
A research team led by Shuai Yan of The University of Texas at Austin set about obtaining radar data for the region and measuring the Earth's magnetic field over a period of three years.
A large patch of ice was revealed by analysis of the radar data. Lake Snow Eagle is one of the largest subglacial lakes ever discovered.
When I first saw that bright radar reflection, I jumped.
The body of water is 2 miles below the ice sheet. It is 42 kilometers in length and 15 kilometers in width and has a depth of 200 meters.
The radar reflections show that there is more than just water in the hidden lake.
There is a layer of unconsolidated material at the bottom of the lake. The team believes that it must have been there before the ice sheet formed.
Martin Siegert of Imperial College London in the UK says that the lake has been accumulating for a long time and that it could potentially take us through the period when the ice was gone.
We don't have a single record of all those events in one place, but the bottom of the lake could be ideal.
It is trapped under several kilometers of ice in one of the most hostile environments on Earth, so getting to the lake to investigate it further is likely to be the next challenge.
The team wants to install a station close by to facilitate future efforts to study the lake.
The research has been published.
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