They detected a heavy hydrogen molecule called hydrogen deuteride.

他们探测出了一种叫做氘化氢的高质量氢分子。

Heavy hydrogen has a neutron as well as a proton in its nucleus.

重氢的核内有一个中子和一个质子。

Comet water and asteroid water have different ratios of these heavy hydrogens to normal hydrogens.

彗星水和小行星水的这些重氢与普通氢的比例不同。

The dirty iceballs, we call comets, are a logical candidate for the source of our water, but were ruled out when we discovered that they are far richer in heavy hydrogen than Earth water.

肮脏的冰球，我们称之为彗星，是我们水之源的合理候选者，但当我们发现它们的重氢含量远比地球水丰富时，就被排除了。