Hydrogen


 * "One moon circles!"
 * - Alien message describing hydrogen

Hydrogen is a chemical element with the atomic number 1 on the periodic table. Its atomic symbol was generally "H" but it also sometimes appeared as "Cs". 

Hydrogen is a highly inflammable diatomic gas with the molecular formula H2. It is in a class by itself as the most basic, and most abundant, element in the known universe, constituting 75% of the universe's elemental gas. Under standard pressure and temperature, hydrogen is a colorless gas. It is the least dense gas known and its very low boiling point of 20.7 Kelvin reflects its non polar character and low molar mass. Its atomic structure consists of one proton and one electron. Hydrogen has three isotopes, two of them stable (protium and deuterium) and one radioactive (tritium). Of the three isotopes, only the first two (often simply referred to as "hydrogen") are found in nature in measurable quantities. The H2 molecule has a "threshold" of 14.7 electron volts. 

The Lothra are a hydrogen-breathing species. 

In 2151, Commander Tucker referred to the risky job astronauts did with the use of rockets: "In the old days, astronauts rode rockets with millions of liters of hydrogen burning under their seats. You think they said, gee I'd love to go to the moon today but it seems a little risky?"

In 2367, the USS Enterprise (NCC-1701-D) released large quantities of hydrogen from their Bussard collectors to escape from a Tyken's Rift. The hydrogen, when combined with a calendenium-analog being released from an unknown alien vessel, created an explosion violent enough to rupture the rift, freeing both ships. The explosion released more energy than the combined firepower of Enterprise-D's phasers and photon torpedoes. 

Related links

 * Bussard collector
 * Hydrogen occurs in many forms and compounds:
 * deuterium
 * hydrogen-alpha
 * hydrogen cloud
 * hydrogen fluoride
 * hydrogen sulfate
 * hydrogen sulfide
 * hydrocarbons
 * liquid hydrogen
 * tritium
 * water (polywater)