Once upon a time in a land far, far away, there only existed four basic elements: earth, water, air and fire. The ancient Greeks believed that these four elements constituted everything – in varying amounts and in varying proportions.
In our last post we took a glimpse at auroras in the making – a spectacular light show staged not by a Roman deity sadly, but by the solar wind. Today we will see where this solar wind originates from (the Sun, unsurprisingly) and see how the draughts of the stars yield the lights of the skies.
We begin our journey at the advent of the Stone Age. Human-like species, or hominids, aren’t able to run as fast as their prey, nor do they stand an earthly chance of surviving brawls with other predators. They can, however, yield a much more powerful weapon – their intelligence. They learn to utilise stone tools in order to gain a technological advantage, and they learn to yield stone weapons in order to exercise their superiority over other species. Here commences the birth of civilisation.
Fast-forward three and a half million years and we arrive at the Bronze Age. The Bronze Age is considered to have begun during the fourth millennium BC with the onset of the production of bronze – an alloy consisting of a copper majority with a supplement of tin. By combining the attributes of two metals, the homo sapiens concocts a metal with strength and durability unmatched by any other material at the time. Stone certainly cannot contend.
Fast-forward another mere three millennia and we arrive at the Iron Age. The Iron Age is considered to have begun during the early first millennium BC and to have ended by the Middle Ages. Iron, although simpler in structure than bronze, is a more difficult metal to extract from its ore. Nonetheless, the reward is immense. The discovery of steel, one of the strongest common materials on the planet, provides human civilisation with another rung in technological advancement.
This is the three-age system. Some say that we currently live in a fourth age – the Silicon Age. Nowadays we can scarcely step in any direction without being in close proximity to a silicon transistor – an essential component of every electronic circuit and which exists in masses of a few billions at a time in a smartphone.
Silicon extends its range of applications to photovoltaic technology. Silicon is by far the most prevalent material in solar cells, the building blocks of solar panels. However, a newer material, perovskite, has captivated the interest of many researchers in the field of semiconductor electronics. Its promisingly high efficiency could put an end to the days of silicon solar cells. For solar cells, could this be the start of the Perovskite Age?