There are always puzzling blue flames over swamps and cemeteries. So far, how these ghostly mistakes were created has been a mystery. Now researchers have apparently discovered the ignition source of these flames: spontaneous discharges on the curved interface of tiny methangas bubbles that rise from the water. If these bubbles come into contact, their pent -up loading differences discharge. These discharges ensure micro flashes, ignite the methaneas and let it burn bluishly.
There are always weak blue-violet flames over swamps, cemeteries as well as marching and other wetlands. These “Ignis Fatuus”, better known as the error or swamp lights, have been notorious for centuries. According to myths, it is a natural master, goblin or the souls of deceased. However, there is a banal explanation for ghostly blue lights: the phenomenon arises when organic matter disintegrates in the soil and methane -containing swamp gas is formed. This methane then burns and creates the bluish flickering flames that seem to float over the wet floor. How the faulgas spontaneously and without heat source ignited in the cool night was so far unclear.
“Irright machine” reveals the process
Researchers around Yu Xia from the Jianghan University in Wuhan have now followed this puzzle. To do this, they built a kind of error machine and used the phenomenon in the laboratory: they developed a generator that generates countless tiny gas bubbles from methane-containing air via a nozzle in a water tank. With high -speed cameras, they filmed what was happening and then evaluated the recordings.
This showed that the methane microbubbles rise in the water and finally burst when they contact the air. Electrical loads collect on the curved interfaces between methangas and liquid. If these bubbles move, merge or share against each other when climbing, it can lead to the load separation. Gas bubbles are created with opposite electrical loads. These strong electrical fields can then spontaneously discharge again when bursting or connecting neighboring bubbles. In the videos this can be seen as a short micro flash. However, the phenomenon only occurs when a lot of methane bubbles rise at the same time and therefore come close to. These flashes then ignite the freely become methane and let it burn it, as the team around Xia explains. This leads to the typical cool flames with a blue-violet luminescence.
Natural ignition source of methane flames
The researchers have found a plausible explanation for the enigmatic mistakes for the first time. Accordingly, there is a completely natural source of ignition for the methane from wetlands. “Our results provide a scientific basis for ‘Ignis Fatuus’ and reveal a general mechanism that can drive redox reactions in natural environments without external ignition sources,” write Xia and his colleagues.
The tests also showed that such micro flashes also arise from gas bubbles from other gas mixtures, including pure air or air-hydrogen mixtures. The electrical loads and discharges of gas bubbles in wet environments are therefore a general, natural phenomenon. The team explains whether this is followed by inflammation or another redox reaction, the team explains. In the case of methane -containing swamp gas, there are justice.
Source: Yu Xia (Jianghan University) et al.; Proceedings of the National Academy of Sciences, DOI: 10.1073/PNAS.2521255122