The Planets in Astrology: Terrestrial Worlds (Mercury, Venus & Mars)

As the only predictable moving bodies in a sky full of fixed stars, the planets have always offered a certain mystique and fascination for us human beings who stare up at them. Whether an Ancient Egyptian navigator with papyrus scroll and their naked eyes or a modern astro-geologist with their very large telescopes and mass spectrometers – we all look at the planets to further our quest for knowledge.

But what do these planets mean to astrologers today, and how did those meanings evolve? In the first of a new series, heading outwards from the Sun, we will look at each planet of the Solar System in turn and reveal what they could mean in your life. This week, we begin with the three terrestrial, or rocky, planets that are closest to the Sun: Mercury, Venus and Mars.


The innermost planet, Mercury is named after the Roman messenger god, and his Greek equivalent Hermes. This is an apt comparison, as this relatively small planet zips around the Sun in a speedy 88 days.

The name Mercury is also a near-homophone of the words for Wednesday in many romance languages, such as Mercoledi in Italian and Mercredi in French. In Astrology this has translated to Mercury ruling over Wednesday. Perhaps because of its association with messenger gods Mercury is also often seen by astrologers as symbolic of communication, travelling, writing and information (amongst other aspects of life). Mercury is also the ruling planet of Gemini.


The second planet from the Sun, Venus has been associated with love and lust throughout most of human history. The second brightest object in the night sky, after the Moon, Venus is the ruling planet of Libra. It draws its name from the Latin words venenum, meaning venom, and vener which means sexual desire.

Somewhat contradictorily, knowing the associations with poison tinged desire that has often accompanied the planet in the minds of the ancients, it has become known in modern astrology as a planet of balance and harmony and from there draws its links to Libra.

Venus is the patron planet of Friday, and again its name can be seen in the root of the romance languages’ names for that particular day: Viernes, Vendredi and Vernerdi to name a few.


The planet Mars, with its distinctive red colouring, has always been seen as portentous by stargazers down on planet Earth. It takes its modern name from the Roman god of war, also known as Ares in Greek mythology. In a cosmic coincidence, that the ancient mythmakers could not have known, Mars’ surface is red because of an abundance of oxidized iron – the same reason that our blood turns red when exposed to the air. Apt for a planet ruled by war!

In astrology, this translates to a planet ruled by the sign Aries that signifies the strong-willed, the courageous and the strong; but also the violent and aggressive. Mars is also the ruler of the first house and is associated with Tuesday, from which many of the romance languages also take their name for the day.