Or, if not, the moon may never have had the magma ocean that scientists think covered its surface soon after it formed.

若非如此，月球可能从来都没有出现过岩浆海洋。之前科学家们曾认为，月球形成后不久，其表面处于岩浆的状态。

youdao

In order for the tide waves to move fast enough at the equator to keep up with the moon, the ocean would have to be about 22km deep.

即使潮波在赤道上移动的速度跟得上月亮，海洋深度必须为22公里左右。

youdao

Perhaps the moon never even had a magma ocean and the rocks were formed another way, they suggested.

他们提出，也许月球甚至从未存在过岩浆海洋或以另一种方式形成的岩石。

youdao

Ninety percent of the ocean floor has not even been charted, and while we have been to the moon, the technology to explore the ocean's floors is still being developed.

CNN: Mars can wait. Oceans can't

We've sent more people to the moon than the deepest parts of the ocean.

CNN: Quest for exploration

Apollo 17, the last manned expedition to the Moon, splashed down in the Pacific Ocean on Dec. 19, 1972.

FORBES: The Return of "Buzz Aldrin's Race into Space" Game