Dec 22, 2021 08:00:00

What is the result of observing the mysterious 'how lightning is born' with a radio telescope even in modern science?

In fact, 'how lightning is born' has not been clarified even by modern science. In order to solve this mystery, a new radio telescope,

LOFAR (LOw Frequency ARray) , which researchers use to observe galaxies, was used to capture the appearance of lightning in high-resolution, 3D data.

Radio Telescope Reveals How Lightning Begins | Quanta Magazine
https://www.quantamagazine.org/radio-telescope-reveals-how-lightning-begins-20211220/

The Spontaneous Nature of Lightning Initiation Revealed | Earth and Space Science Open Archive
https://www.essoar.org/doi/10.1002/essoar.10508882.1

Research on lightning has existed for a long time, and in 1752 Benjamin Franklin conducted an experiment using an octopus and revealed that the true nature of lightning is electricity. However, in reality, the mystery of 'how lightning is born' has not yet been solved.

The main hypothesis of the process of lightning generation is, 'In a thundercloud, when a small ice crystal rises and falls as a hail, the negatively charged electrons in the crystal are scraped off, and the upper part of the cloud is It is positively charged and the lower part is negatively charged. This creates an electric field that produces a huge spark. ' However, it is said that the electric field in the clouds is too small to generate sparks, and even if we actually send rockets and balloons into the thundercloud and examine it, we have not observed enough electric fields to generate sparks. that's right.

The challenge in unraveling the mystery of lightning is that the clouds are opaque and even a highly accurate camera cannot capture the moment when lightning is born. Therefore, Professor Joseph Dwyer, a physicist at the University of New Hampshire, decided to use the radio telescope LOFAR in the Netherlands.

The following is LOFAR.

LOFAR usually observes phenomena that occur in space, such as intergalactic gas and magnetic storms. Lightning emits a radio pulse with light, which, unlike light, can pass through thick clouds. By detecting this wireless pulse, LOFAR can map lightning in high resolution and three-dimensionally. Attempts to map lightning with wireless detectors are not new, but many are low resolution and two-dimensional, which is different from observations using LOFAR.

You can see the animation of the data observed by LOFAR by clicking the image below.

In August 2018, the research team analyzed the data collected using LOFAR and revealed that the radio pulse was emitted from a depth of 70 meters in the thundercloud. According to the research team, the observed radio pulse patterns support two ideas about lightning formation. One is the hypothesis that 'cosmic rays collide with electrons in thunderclouds and the electric field is strengthened by an electron avalanche.' The other is 'Ice crystals collide and one end is positively charged and the other end is negatively charged. One end of the positively charged ice collects more electrons from the air and' ionized air 'from there. The ribbon, the so-called streamer (discharge path), heats up the surrounding air, pulling more electrons away from the air and causing more current to flow through the ice crystals, eventually Thunder is formed in the air. '

Researchers believe that the formation of large amounts of streamers causes the radio pulse to increase exponentially, forming lightning when the electron avalanche stops. The epidemic of the new coronavirus infection (COVID-19) has resulted in blockades around the world, reducing the number of pollutants in the air that are the 'nucleus' of ice crystals. It has been observed that the occurrence of lightning has decreased by 10% during this period, and the researchers' ideas are in line with this observation.

However, in this research, the ice particles that ionize the air are not directly projected, and even 'where do the first electrons come from' and 'how the discharge occurs near the ice particles'. Was not revealed. For this reason, how streamers produce lightning remains a mystery. On the other hand, lightning research has not been able to construct accurate simulations due to lack of high-resolution data, so the data obtained from this research is expected to be an important step in lightning research.