Wordly Wise: Some Moon talk ahead of Chandrayaan 3’s lunar rendezvous

Borrowed from French, rendezvous has been widely used in English. In its original sense, it means a place appointed for assembling or meeting. It also refers to a plan to meet somebody at a particular place at a particular time. In the 20th century, the word literally took off into space, becoming the term used to describe when two objects in space will meet. For instance, while announcing details for Chandrayaan’s take-off, ISRO said that we will see a possible moon rendezvous on August 23 or 24.

The word also refers to an appointed place for the assembly of troops, ships, or aircraft after an operation. It has yet another meaning: a meeting place for a romantic encounter. As a verb, it means to meet at a pre-decided place and time.

Apogee is a point in the orbit of any satellite, like the Moon, at which it is the farthest from the celestial object, the Earth in this case, around which it revolves. It is formed by Greek apo (away from) and ge (earth). In common usage, it is often used in its figurative sense which means the highest point of a career, endeavour or state of being. For example: With the World Cup win, Lionel Messi is at the apogee of his career.
Its antonym is perigee but does not find a figurative use.

Regolith is the residual material that lies over a layer of solid bedrock on the Moon, or any other celestial body, including Earth. Prior to the first unmanned spacecraft landings on the moon in the 1960s, some astronomers believed that the regolith will give way under the weight of the spacecraft – the landers would simply sink in it. Later missions and manned landings, however, found that the regolith was slightly compressible but firm enough to be supportive. The word comes from rhegos (blanket) and lith (stone), literally meaning “blanket rock”.

A module denotes a section that can be connected or combined to build or complete something larger. The word comes from Latin modulus, meaning “small measure”. Chandrayan-3 comprises three modules – Lander module, Propulsion module and a Rover. The three are designed to perform separate functions.

An interesting coinage related to the study of the Moon is selenography. In Greek and Roman mythologies, Selene represents the Moon goddess, who was worshipped at new and full moons. Her siblings were Helios, the god of the Sun, and Eos, the goddess of dawn. By the 17th century, selenography came to be used for the science of the physical features of the moon and its geography.

Mare is the Latin word for sea. Many 17th century Latin works used it to denote the dark areas of the moon’s surface. Today it is known that the moon is dry and its “seas” are in fact old basins containing congealed lava flows that formed the dark plains. They are marked by craters, ridges, depressions and faults. The higher elevations of the moon are known as highlands or terra, which is the Latin word for land.

A portmanteau of ‘mass’ and ‘concentration’, a mascon is any of the high density regions that are below the surface of lunar Maria (plural of Mare). Mascons tend to disturb the motion of a spacecraft due to their excessive gravitational pull. Maria are the largest topographic features on the moon and can be seen from earth. Together with the highlands, they form the face of the ‘man in the moon’.

While the next month’s rendezvous is anxiously awaited, we remember Arthur C Clarke’s words: “The moon is the first milestone on the road to the stars.”