An attempt to collect a sample of ancient air from a 4,600-year-old pit near the Great Pyramid of Giza has failed because the chamber's builders apparently did not seal it properly, two American scientists said.
The limestone pit was constructed in the shadow of the pyramid built for Cheops, a Pharaoh who ruled Egypt about 4,600 years ago.
The chamber had remained untouched since September, when the team of Egyptian and American scientists bored a hole in the ceiling of the pit, using a drill specially designed to prevent air from leaking in or out.
Hoping to gain knowledge of the ancient atmosphere, the scientists obtained air samples from three levels inside the pit, using an air probe inserted through the air lock.
They sought to determine how the Earth's atmosphere had changed during the past five millennia and the reasons behind today's increasing levels of carbon dioxide and methane and the decreasing level of ozone.