The images reveal details that would hardly be visible to the naked eye. The Brazilian scientist Marcelo Saba and his team from the Brazilian space research institute INPE were able to film a lightning strike in extremely good resolution. You can see: 31 lightning bolts shooting up towards the sky from lightning rods on buildings. Lightning then breaks through the image from above at more than 300 kilometers per second. Saba and his team filmed the thunderstorm on a summer evening in 2021, in the Brazilian city of São José dos Campos, northeast of Sao Paulo.
How do such flashes occur? Lightning bolts shooting from the ground toward the sky happen less than a millisecond before lightning strikes from above. The video shows brush-like patterns around the lightning bolts coming out of the downconductors. These branches are called corona in science. The so-called catch charges that strike out of the arresters are positively charged and are caused by the negative charge of the lightning that comes from above.
How are these flashes formed?
Meteorologist Andreas Friedrich from the German Weather Service explains: “When the negatively polarized discharge from above meets the positive one from below, a short circuit occurs.” Then about 500,000 amps flow for a very short time. The air is heated to around 30,000 degrees Celsius within fractions of a second. Most of the lightning that goes from heaven to earth are negative charges. Only about ten percent of the time do positive charges come from above. In these cases, the catch charge that shoots up is also negative. Catch charges increase the likelihood that lightning will strike a lightning rod, where the electricity will then discharge into the ground.
It has been known since the 18th century that lightning conductors basically work. In the 1740s, the American scientist Benjamin Franklin invented protective structures. In one experiment, he is said to have let a kite soar on a metal cord during a thunderstorm. After lightning struck the aircraft, the metal cord carried electricity into the ground. Up until Franklin’s findings, it was disputed whether lightning was electric at all. In the years that followed, wealthy people in particular had lightning rods installed on their buildings. Today, protective devices are standard equipment in buildings. However, while arresters have advanced greatly in technology since Franklin’s lifetime, they do not always offer protection from the dangers from the skies. Even in the case now being filmed, the arresters could not protect the building from an impact.
Few people have managed to film Space Stems
The video of Saba and his colleagues shows how the lightning strikes a chimney. Branches about three meters long can be seen around it. About four meters from the main channel of the flash, glowing plasma formations called space stems form. In physics, plasma is a mixture of ions, free electrons and neutral atoms or molecules. Few people have managed to film Space Stems so far.
The flashes on the video are nothing special, but the pictures are. “Such shots of a flash in slow motion are very unusual,” explains meteorologist Friedrich. Saba and his team were only able to capture the spectacle in such detail because they used high-speed cameras capable of 40,000 frames per second. For comparison: The camera of the iPhone 16 takes 30 frames per second by default. In addition, the researchers’ cameras had a very high resolution. With an ordinary mobile phone camera, the flashes would only be visible as a blur. Details such as the corona ramifications remained hidden.
The INPE team published a scientific paper on the recordings in the scientific journal Geophysical Research Letter.