Of the meteorological phenomena, thunderstorms are perhaps the most mysterious. Many internal processes of an ordinary storm are incomprehensible even to scientists, not to mention the common people. It is logical that sometimes the most powerful peals of thunder instill in people an irrational fear, which is easiest to overcome by understanding what thunder is.
A bright flash, which marks the beginning of a serious downpour, is called "lightning". In the clouds during the rain, a huge electric charge accumulates, and it is logical that he is looking for a use for himself. Since there is nothing to "catch" on from above, the energy can only hit the ground (or something metallic - a lightning rod, for example). The charge released in this case is enormous: the voltage reaches 50 million volts!
It is logical that the discharge significantly affects everything around it, in particular, the air in the immediate vicinity. The colossal energy in a split second heats the surrounding space up to 30 thousand degrees Celsius, due to which a sound wave called thunder is immediately born.
Light travels many times faster than sound, therefore, if everything happens at the same time at the point of impact, then a noticeable delay appears already at a distance of a couple of kilometers. This is the first reason why thunder is not dangerous: it is only a consequence, when you hear it, you can be sure that the main blow has already passed.
But, if lightning flashes only once, why does the noise last for several seconds in a row? Imagine yourself in the woods. If you shout loudly enough, then the sound will bounce off the surrounding objects (trees, leaves, ground) and return to you in the form of an echo. The sound of thunder is somewhat louder than your scream, but the principle remains the same: reflecting from the surface of the earth, clouds, distorting in the air, it reaches a point not immediately, but somewhat "stretched". Remember that no one has suffered from the echo yet: in this sense, thunder is not dangerous at all.
However, not everything is so rosy. It is now clear that thunder is just sound, but sound can also hurt: if it is too loud, of course. Directly near the lightning, vibrations reach 120 decibels, which is just the hearing limit of the average person and is approximately equal to the noise of an airplane taking off. If you are not accustomed to the explosion of grenades in your immediate vicinity and do not have an ear for music, then untrained eardrums can be significantly affected if you find yourself close to a lightning flash.
