杰瑞在月球上的目標是一個這樣的角形反射器
that were left by astronauts from the first Moon walkand later Apollo missions.
是由第一個在月球行走的宇航員 以及后來的阿波羅計劃安置的
It takes just 2.5 seconds for the light to return to Earth.
激光只需2.5秒就返回地球
Jerry has measured this figure every day for decades.
杰瑞已經測量了數十年時間
And his results reveal something remarkable.
而他的數據清楚的顯示
The Moon is receding 3.8 centimetres per year,
月球每年遠離地球3.8厘米
which kind of surprised me, I didn't really give it a thought
真的很奇怪我從沒想過會這樣
whether it was standing still or moving, but it is, it's moving away.
它并不是靜止或者移動它正在遠離
And eventually, we'll lose it.So the Moon will not be with us forever.
總有一天,我們會失去月球 所以月球不會永遠和我們在一起
Eventually, it will drift away into space and Earth will lose its climatic stability.
最后,它會漂流到太空里 地球會失去它的穩定氣候
But there's no need to panic.It'll take billions of years.
但是沒有必要恐慌 這個過程將花費數億年
Earth's chance collision with its twin was perhaps the critical moment in its history.
地球和它的孿生星球撞擊 也許是地球歷史上最關鍵的時刻
By this theory, it ensured that the planet held on to its protective atmosphere.
它使得地球可以留住保護自己的大氣層 它使得地球可以留住保護自己的大氣層