未解之謎:鹽湖湖牀上自行移動的石頭
Racetrack Playa is a dry lake bed located 3,608 feet above sea level in Death Valley National Park, California. The playa is named after the "racetracks" left by stones that mysteriously skid across its surface.
跑道幹湖是坐落在加利福尼亞國家公園死亡之谷中的一個乾涸的湖牀，海拔3608米。之所以被命名爲“跑道”，跟在湖牀中的石頭有關，這些石頭從湖牀表面劃過，並留下一道道讓人匪夷所思的滑行“軌跡”。The Racetrack is primarily covered with hexagonal saucers of dry mud, left after a very short season when the lake bed is covered with a shallow layer of water after rains wash down from the surrounding mountains and into the playa. But marring this surface is the creepy evidence of stones that move on their own.
湖牀表面覆蓋着一層龜裂的幹泥，這是由於每年有一段時間雨水從周圍的山上流下來，在湖匯聚成淺淺的一層，湖水蒸發之後，就剩下了龜裂的湖泥。但是這些能自行移動的石頭在此顯得極不協調。Sliding slowly without any intervention for distances as long as 1,500 feet, the sailing stones have never been filmed in motion, yet they're definitely on the move. The strange phenomenon only happens every few years, and the tracks are left for several years for visitors to ponder. One hypothesis is that winds -- which can howl at up to 90 mph -- push the stones across the slick mud left as the lake bed dries up after a downpour. A second similar hypothesis poses that after a thin sheet of rain falls over the playa and night temperatures drop to below freezing, a layer of ice forms across the surface of the lake bed and the stones slide across the ice with the wind.
如果沒有任何干預，這些石頭能慢慢地移動長達1500英尺的距離。雖然沒有用儀器記錄下來，但是這些石頭絕對是在運動着。這個奇怪的現象每隔幾年發生一次，留下一道道痕跡給遊客們去思考。有人認爲是風的作用——這裏的風速最高可以達到90英里每小時，乾涸的湖牀在一場大雨之後湖底因爲積水而變的很滑，就有可能產生這種結果。第二個類似的說法認爲，如果下一場小雨，加上夜間零度以下的溫度，湖牀表面就有可能結冰，這樣風吹着石頭移動起來就比較合理了。
The only way to find out for sure would be to set up cameras and environmental sensor tools to understand just what makes these rocks move. Until then, they will remain a mind-blowing mystery!
找到真相唯一的方法就是在此處設立攝像機，進行環境監控。在真正找到答案之前，這些石頭仍然讓人百思不得其解。
