Mount Everest, standing 8.85 kilometers above sea level, is Earth's tallest mountain.

珠穆朗玛峰海拔8.85公里，是地球上最高的山峰。

And Mount Everest is still growing.

珠穆朗玛峰仍在增长。

Mount Everest and the rest of the Himalayas are continuing on an upward movement that began at their birth around 50 million years ago. The mountains are a product of a collision between Eurasia and the Indian subcontinent.

珠穆朗玛峰和喜马拉雅山的其他山峰自大约 5000 万年前诞生以来，一直在继续向上运动。 这些山脉是欧亚大陆和印度次大陆碰撞的产物。

But Everest is growing more than expected. And, scientists now think they know the reason why.

但珠穆朗玛峰的增长速度超出了预期。 而且，科学家们现在认为他们知道其中的原因。

Everest's growth has to do with the major joining, or merger, of two nearby river systems. The Kosi river joined with the Arun river around 89,000 years ago, the researchers estimated.

珠穆朗玛峰的增长与附近两个河流系统的主要连接或合并有关。 研究人员估计，科西河在大约 89,000 年前与阿伦河汇合。

This change in the area's river system has led to Everest gaining around 15-50 meters in height.

该地区河流系统的变化导致珠穆朗玛峰高度增加了约 15-50 米。

That suggests an upward movement rate of about 0.2-0.5 millimeters per year.

这表明每年向上移动的速度约为 0.2-0.5 毫米。

The geological process at work, researchers said, is called isostatic rebound.

研究人员表示，起作用的地质过程称为等静压回弹。

Isostatic rebound involves the rise of land masses on Earth's crust when the weight of the surface declines. The crust, Earth's outermost part, floats atop hot, semi-liquid rock.

等静压回弹涉及当地表重量下降时地壳上陆地质量的上升。 地壳是地球的最外层部分，漂浮在炽热的半液态岩石之上。

In this case, the joining of the rivers resulted in increased erosion which carried off large amounts of rock and soil. This reduced the weight of the area near Everest.

在这种情况下，河流的交汇导致侵蚀加剧，带走了大量的岩石和土壤。 这减轻了珠穆朗玛峰附近地区的重量。

"Isostatic rebound can be likened to a floating object adjusting its position when weight is removed," said Jin-Gen Dai of China University of Geosciences in Beijing.

北京中国地质大学的戴金根表示：“等静压回弹可以比喻为当重量被移除时漂浮物体调整其位置。”

Dai is one of the leaders of the study published recently in Nature Geoscience.

戴是最近发表在《自然地球科学》上的这项研究的领导者之一。

"When a heavy load, such as ice or eroded rock, is removed from the Earth's crust, the land beneath slowly rises in response, much like a boat rising in water when cargo is unloaded," Dai added.

戴补充说：“当冰或被侵蚀的岩石等重物从地壳上移走时，下面的土地会相应地缓慢上升，就像卸载货物时船在水中上升一样。”

The researchers, who used numerical models to study the development of the river system, estimated that isostatic rebound accounts for about 10 percent of Everest's yearly upward movement, or uplift rate.

研究人员使用数值模型研究河流系统的发展，估计珠穆朗玛峰每年向上移动或抬升率的 10% 左右是由均衡回弹造成的。

This geological process is seen in other places around the world.

这种地质过程在世界其他地方也有发生。