In this connection, in the middle of the twentieth century. there was a need to find new sources of energy?

Coal was one of the main sources of energy until the 21st century.

But in the middle of the 20th century, everyone quickly began to look for alternatives.

This was due to the fact that the ecological situation on Earth was simply terrible due to the fact that people were extracting too much energy source, seriously polluting the earth.

Also, the stocks themselves were not endless. They gradually ended.

Well, new inventions also needed a better source of energy, since the old one was getting worse and worse for them.

Therefore, they were looking for new sources.