From Thor we get thunder

As Sydneysiders suffer our dog days (see note below) the Bureau of Meteorology appease us by suggesting that thunderstorms are on their way. We pray for the sound of thunder to bring a change from the constant heat.

Thunder is the sound caused by lightning as it passes through the air. Lightning heats the air around creating a high-pressure area. The air expands supersonically creating a shock wave which we hear as thunder.

Our forefathers did not think in terms of shock waves but in terms of thunderbolts and associated the powerful noise of thunder with their gods. In Greek myth, Zeus was a sky god who been given thunder and the thunderbolt by the Cyclopes for setting them free of Cronus. Jupiter or Jove, in Roman mythology, was the king of the gods and the god of the sky and of thunder. In Judeo-Christian tradition thunder was the voice of God (Psalm 18:13):

The Lord thundered from heaven;
the voice of the Most High resounded

In Scandinavian mythology Thor was the god of thunder. And it is from Thor that most of the Germanic languages, including English, have taken their words for thunder. In Old Norse, por, and in Old High German donar, the words for thunder were the same as for Thor the god. In modern Swedish the word for thunder is tordön which literally translates as Thor’s din.

The Anglo-Saxon god that was equivalent to Thor was Thunor. It is from him that we get the English word thunder with the ‘d’ having slipped in (an example of epenthesis where a consonant becomes added to help pronunciation), as it did in the Dutch word donder closely related to the modern German word donner without the ‘d’.

So it would appear that we still look to our pagan gods when we pray for thunder and the coming of rain to relieve us from the long dog days of summer.

NOTE: There was an unusual touch of classical Rome in the Daily Telegraph yesterday (link no longer available) when it referred to Sydney’s longest heatwave as our “dog days“—the sweltering days of summer when the temperatures are too hot and the air is stagnant. The Romans used the term because Sirius, the dog star from the constellation Canis Major (big dog) and the brightest star in the night sky, rose with the sun over the hottest part of the northern hemisphere summer. The Romans thought that the dog star added to the sun’s heat, which, of course it didn’t.