youdao

Some of this energy congealed into particles, which assembled into light atoms like hydrogen and helium.

有些能量凝结成了粒子，这些粒子组合形成了轻原子如氢和氦。

youdao

Instead the nebula glows with light from hydrogen gas being charged by the stars' radiation.

星云的光辉则是来自在恒星强烈辐射作用下带电的氢气。

youdao

One shows the remains of a dying star four thousand light years away which has thrown off a cloud of glowing hydrogen gas.

VOA: special.2009.09.30

The barrier to using the devices in vehicles is no one knows how to carry enough hydrogen, a light and flammable gas that is difficult to compress, to be useful.

CNN: Bus showcases fuel cell technology

By shining laser light onto hydrogen or antihydrogen and observing which wavelengths are absorbed, the energy levels of the two can be compared in detail.

ECONOMIST: Antimatter: Gotcha! | The

Neutrons ejected from a watery surface move much more slowly than those from a rocky one, because the hydrogen nuclei in water are light enough for an exiting neutron to knock around much like one billiard ball hitting another a process that slows the neutron down.

ECONOMIST: Divining water