Dimorphous (pronounced dahy-mawr-fuhs)
(1) Occurring or existing in two different forms.
(2) In botany, plants with roots with two distinctive forms for two separate functions.
(3) In botany, as frond dimorphism, differing forms of fern fronds between the sterile and fertile fronds.
(4) In botany, as dimorphic fungi, fungi which can exist as both mold and yeast.
(5) In cell biology, as phenotypic dimorphism, a switching between two or more cellular morphologies.
(6) In zoology, a phenotypic difference between males and females of the same species.
(7) In nuclear physics, a cell where the nuclear apparatus is composed of two structurally and functionally differentiated types of nuclei.
(8) In geology, the property of some substances to exist in two distinct crystalline forms.
1801: From the Ancient Greek dímorphos (of two forms), the construct being di + morphē (form, shape). The suffix di- was from the Ancient Greek δῐ- (di-), from δῐά (diá) (through), from the Latin di- (two, twice or double (the synonyms were duo-, bi- & bis-)) and was an alternative form of dis-, shortened when placed before l, m, n, r, s (followed by a consonant), and v; it was also often shortened before g, and sometimes before j. Morphe was a back-formation from morpheme, from the Ancient Greek μορφή (morphḗ) (form, shape); the similar German Morph is from morphem and attested since the 1940s. In formal grammar and structural linguistics, morphe is a physical form representing some morpheme in language; a recurrent distinctive sound or sequence of sounds. In linguistics, an allomorph is one of a set of realizations that a morpheme can have in different contexts. The –ous suffix is from the Middle English -ous, from the Old French –ous & -eux, from the Latin -ōsus (full, full of); a doublet of -ose in an unstressed position. It was used to form adjectives from nouns, to denote possession or presence of a quality in any degree, commonly in abundance. In chemistry, it has a specific technical application, used in the nomenclature to name chemical compounds in which a specified chemical element has a lower oxidation number than in the equivalent compound whose name ends in the suffix -ic. For example sulphuric acid (H2SO4) has more oxygen atoms per molecule than sulphurous acid (H2SO3). The class of words to which dimorphous belongs originally was most often used in botany to describe plants with one (monœcious), two (diœcious) or there (trimorphic) forms. Dimorphous & dimorphic are adjectives, dimorphism is a noun and dimorphically is an adverb; the noun plural is dimorphisms.
First observed in 2003, Dimorphos is a small asteroid, technically a minor-planet moon of a synchronous binary system, Didymos, discovered in 1996, the primary asteroid. Unfortunately, after the usual committee processes of the Working Group Small Body Nomenclature (WGSBN) of the International Astronomical Union (IAU), the astronomers’ preferred nickname "Didymoon" was declined, the official name Dimorphos granted on 23 June 2020. With a diameter of 170 metres (560 feet), it’s among the smallest astronomical objects to be given a permanent name.
Dimorphos is of greater interest than most asteroids because it’s the target of NASA's Double Asteroid Redirection Test (DART) mission, the impact scheduled for 26 Sep 2022. The DART project is a proof-of-concept mission to test the viability of using small-scale physical impacts as a means to divert the trajectory of asteroids or other objects likely to hit Earth. The DART process too is dimorphous and only partially self-destructive, the European Space Agency’s (ESA) Light Italian CubeSat for Imaging Asteroids (LICIACube) travelling attached to the doomed projectile, separating ten days before impact, that mission to observe and record the impact’s consequences. Although about the size of a small car, with the solar panel wings unfurled, DART is as big as a 32-40 seat bus while LICIACube, equipped with the LICIACube Unit Key Explorer (LUKE) and LICIACube Explorer Imaging for Asteroid (LEIA) optical cameras is a small package with a mass of about 30 pounds (14 kilograms), barely bigger than a respectable handbag. The size and weight of the ESA’s equipment was dictated by the limits imposed by the need to restrict the volume to what could be carried by DART for the entire journey.
The name, derived from the Ancient Greek Dimorphos (having two forms) refers not to what the unsuspecting rock is but what it will become, the second of its forms emerging after DART strikes. Dimorphos will become the first celestial body in history, the form of which will substantially be changed by human intervention and this may therefore be something unique in the universe. The point of the experiment is to determine if impacts at speed (and therefore of greater energy, DART planned to hit at 15,000 mph (24,100 km/h)) by small objects is sufficient to deflect objects by enough to change their course. The theory is that if undertaken at long-distance, only a tiny change in trajectory should be enough to avert an object from a collusion path with Earth. NASA launched DART on 24 November 2021.
Ten days before DART strikes Dimorphos, LICIACube will be released, firing its thrusters to separate from the mother-ship, then positioning itself to be at the correct angle to optimize the viewing window while ensuring it’s remains at a distance close enough to capture the desired details yet not so close as to risk damage from whatever debris the impact may eject. The DART images immediately prior to impact will actually be a real-time stream; travelling at the speed of light, the data will take some 38 seconds to travel the 6.8 million miles (10.9 million km) to Earth. LICIACube will store the data and continually transmit images in the months after DART’s demise.
Although the target asteroid is tiny compared to the cataclysmic Chicxulub behemoth which struck Earth 66 million years ago, ending the long age of the dinosaurs, the data derived from the DART experiment should be robust enough to be scalable and mathematical models will be developed to work out how much energy will need to be deployed to gain the desired effect, hence the often speculated use of nuclear explosions if the troublesome rock is really big. Asteroids, primordial rocky remnants from the solar system’s formation some 4.6 billion years, are not uncommon and some are already on a path to strike earth sometime during the next few million years so the threat is real, even if the timing is unpredictable.
In fictional depictions, well known examples of dimorphic roles include (1) the one individual manifesting in two very different forms such as the protagonist(s) in Robert Louis Stevenson's (1850–1894) Strange Case of Dr Jekyll and Mr Hyde (1886), (2) one which explores aspects of duality which manifest as two characters with lives or personalities intertwined to the extent that the distinction between the two is sometimes lost (Waiting for Godot (1953) by Samuel Beckett (1906-1989)) or used as a literary device (The End of the Affair (1951) by Graham Greene (1904-1991)) & (3) the one actor playing two different characters who are in some way closely related or associated (Lindsay Lohan in The Parent Trap (1998)). However, where an actor plays two quite distinct roles (Peter Sellers (1925–1980) in Dr Strangelove (1964) although he actually played three) this is not thought dimorphic because the characters are connected except through the device of the plot.
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