Neutralhydrogen emits radiation on a characteristic 21cm wavelength, while ionised hydrogen does not.
中性氢辐射出离子化氢所没有的特有的21厘米波长。
2
IBEX has also generated the first maps of neutralhydrogen and oxygen atoms entering the solar system from interstellar space.
IBEX还产生了第一张从外部空间进入太阳系的中性氢原子和氧原子的地图。
3
It was during the Dark Ages that the universe cooled enough to allow molecular hydrogen to form, filling the cosmos with a diffuse cloud of electrically-neutral gas.