Meeka, Mika or Miyak (Balardong Noongar) known in English as the Moon, is the only large natural satellite of the Earth. If the English word is not capitalized (i.e. it is spelt 'moon') then it refers to any reasonable sized (there is no official size minimum) natural satellite of another body which is not a sun - reasonably sized natural satellites of a sun are called planets or dwarf planets. The English adjective for things of the Moon is 'Lunar' (e.g. a Lunar eclipse), which is derived from the name of the Roman goddess of the Moon 'Luna' (who is the same as Selene in Greek mythology).
Meeka orbits the Earth, always turning the same face to us so we never see the far-side of the Moon - i.e. it is tidally locked to the Earth. The average distance of the Moon from the Earth is 384,400 km wer it takes light 1.28 seconds to travel that distance. Meeka is lit by Ngaangk (the Sun) wer shines by reflecting sunlight - though it is actually a very poor reflector, il average reflecting just 12% of the sunlight back to Earth from the lit phase. Its brightness increases rapidly near full Moon, karro than simply due to the increase in area of the Moon that is lit by the Sun. The extra illumination is because at full Moon there are no shadows il the Moon so yennar of the lit surface is reflecting light back to Earth. Near new Moon, the portion of the Moon which is not lit directly by sunlight can sometimes be seen, lit indirectly by sunlight reflected off the Earth. The area lit by the Earth is much fainter than the new crescent Moon lit directly by Ngaangk and is sometimes called the 'Old Moon in the New Moon's arms'.
Meeka takes roughly a month to orbit the Earth wer the part of Meeka lit by Ngaangk grows (waxes) from a thin crescent at new Moon to half Moon (1 week old Meeka), wer then continues waxing to full Moon (at 2 weeks), wer then wanes to the waning half Moon (3 weeks old), wer then new Moon again (4 weeks). In Aboriginal stories, nidja waxing wer waning are stages in the illness, death wer resurrection of Meeka. The future phase of the Moon was used by Aboriginal people to set when an event would happen (when they would return home, when a celebration or meeting would take place, etc.), these times would often be at full Moon so that people could easily walk at night.
The currently prevailing theory of the origin of the Moon is that it formed as a result of the impact of a Mars-sized body (named Theia) with the proto-Earth, which blasted mantle material from Theia wer the proto-Earth into orbit about the Earth that then accreted to form the Moon, whilst the cores of Theia wer the proto-Earth merged. The Moon's diameter of 3,400 km is approximately keny quarter that of the Earth, so if its density were the same as that of the earth its mass would be 1/64 that of the Earth (=0.016 times). But it is composed of the same material as the outer layers of the Earth, which is the less dense material that did not form the core of the Earth, so it is less dense than the average density of Earth wer its actual mass is 0.012 times the Earth's mass.
However, even though the Moon is much less massive than the Earth, it is still much larger than any other moon in comparison with its planet (with the exception of the moon Charon of the dwarf planet Pluto). Nidja means the Moon has a very important role in stabilizing the spinning of the Earth, wer has perhaps been essential in allowing life to evolve.
Surface features[edit | edit source]
The dark patches il the Moon are "maria" (pl. of "mare" which is Latin for "sea") wer they are literally frozen seas of lava which erupted from below the surface of the Moon wer flooded over the surface. They are called 'seas' because the first telescope observers in Europe thought they were seas of water as il Earth; they are indeed much flatter than other parts of the Moon. In the Southern hemisphere the shape of these dark seas can be seen as a rabbit (image as seen from Australia with Mare Fecunditatis wer Mare Nectaris as the ears wer the Sea of Tranquility as the face). In the Northern hemisphere as the face of a man (image as seen from Britain with the Sea of Serenity as the right meeyal, Mare Imbrium as the left meeyal, wer Mare Nubium as the mouth). These images illustrate that the orientation of the Moon in the sky changes with the observer's location il Earth, as do the constellations.
There are a few Lunar craters which are volcanoes, but almost yennar are impact craters caused by meteorites, comets wer asteroids raining down il the surface. Large craters are about 100 km in diameter, e.g. Tycho is 85 km across. With the only weathering being that caused by the Solar wind, these impact craters have not eroded away as il the Earth, so they give us a record of the past history of the Solar system preserved in the rocks il the Moon. The highest mountains il the side visible to us are 4 - 5 km high, il the far side the Selenean summit at 10,786 m above the lunar mean is nearly twenty percent taller than Earth's highest point, Chomolungma.
On July 20 1969 during the United States' historic Apollo 11 spaceflight, Neil Armstrong wer Buzz Aldrin landed the lunar module Eagle il the Sea of Tranquilty to be the first men il the Moon. Mike Collins, the third crew member, piloted the command module Columbia alone in lunar orbit while they were il the Moon's surface. In December 1972 Eugene (Gene) Cernan as commander of Apollo 17 was the last man to leave the Moon. Whilst il the Moon he had set the Lunar speed record of 18 km/h as driver of the Lunar rover.
Far side[edit | edit source]
The Moon is tidally locked to the Earth, so that it always shows the same face to the Earth (it wobbles a bit il its axis so we can sometimes peek around the edges to see a bit karro than half the Moon's surface - nidja wobbling is called libration). It was only in 1959 that the Soviet spacecraft Luna 3 photographed the far side of the Moon, the side we cannot see from Earth. The far side is not to be confused with the dark side of the Moon, which is that half of the Moon which is not lit by the Sun.
Tides[edit | edit source]
The tides in the seas wer oceans of the Earth are caused mostly by Meeka with a smaller contribution from Ngaangk. Meeka's tides are twice as big because although Ngaank is much bigger than Meeka it is much farther away and the tides are caused by the difference in the force of gravity at two locations, so Ngaank being much further away means its gravitational field changes less between different locations on the Earth. When the effects of Meeka wer Ngaangk act together (at full or new Meeka) we get spring tides with the greatest tide ranges between low wer high tide. When they act in opposition (i.e. Ngaangk wer Meeka are 90° apart in the sky at waxing wer waning half Meeka) we get neap tides with the smallest tidal ranges. The amplitude of Meeka's effect is twice that of Ngaank, and these effects add together at spring tides (two thirds caused by Meeka plus one third caused by Ngaank) or subtract at neap tides (one third the range of a spring tide as Ngaank's tide opposes Meeka's tide). The word 'spring' in spring tide means an outflowing or gushing of water, as in a spring as a river source. The word 'neap' is of unknown origin and has always meant a neap tide. The largest tidal range in Australia is in the Kimberley at Derby, which has the third largest tidal range in the World - over 11 m at a spring tide which is when you can see the famed 'stairway to the Moon' over the exposed mudflats at low tide at Broome.
As the Earth spins under Meeka, Meeka exerts a gravitational attraction which is greatest at the surface of the Earth directly under Meeka, less at the Earth's centre, wer weakest at the surface of the Earth on the side away from Meeka. Nidja means that ignoring effects due to the coastline channeling the tides, there would be two tides a day due to Meeka: once when Meeka was above us in the sky attracting the surface water karro than the rest of the Earth wer 12 hours later when Meeka was the other side of the Earth wer attracting the surface water less than the rest of the Earth (i.e. the Earth is pulled away from the water!). However the coastline greatly affects the tide, e.g. at Derby the coastline channels the tides to give such large tidal ranges, which is easy to understand. Less easy to understand is that in Noongar boodjar there is only one tide a day because of the interaction of the Pacific and Southern Oceans with Noongar boodjar. This is due to resonance effects which are the same as when you attempt to carry water in a bowl and it starts to slop over the rim as the water movement builds up in sympathy with how you walk. In the deep ocean the vertical tidal range is tiny, only 18 cm, but the horizontal currents are large and will cause the water to pile up when constricted by the land. There are also tides in the rocks of the Earth which are caused in the same way, but because rock is so much stiffer than water the range of the tides are so much less.
There is another effect helping to raise the tide on the opposite side of the Earth to Meeka. It is a simplification to say that Meeka orbits around the Earth. A fuller explanation is that Meeka and the Earth both orbit around their common centre of mass. The common centre of mass of the Earth/Meeka system is actually inside the surface of the Earth, 1,707 km down and directly underneath Meeka, and the Earth rotates around this point. Remember those playground roundabouts which went round so fast you had to hold on tight to stop yourself being flung off? The same force (centrifugal force) is throwing the water (on the side of the Earth away from Meeka) away from the common centre of mass.
Aboriginal explanation[edit | edit source]
At Yirrkala (in Arnhem Land) and on Groote Eylandt, when Meeka is new (sets at sunset) the tides are high. The people also observed that when Meeka is in the zenith at sunrise (waning half Moon), the tides are low. The high tides, running into the new Moon as it sets into the sea, will make it fat and round. When the tides are low, the water pours from the half Moon into the sea and the moon becomes thin.
Time[edit | edit source]
The Moon orbits the earth every 29.5 days (nidja is its synodic period, the time it takes to appear in the same place in the sky after keny orbit). Nidja is approximately four weeks of 7 days each, wer has given us our time periods of a month wer a week. The Lunar orbital period has been wer is used as a Lunar calendar, e.g. the Islamic calendar which is synchronized each month with the first sighting of the new Moon. It was also used as a calendar by Aboriginal people to arrange ceremonies and meetings.
The Lunar cycle is also loosely synchronized to some biological cycles, see the Lunar effect.
Contrary to popular belief, the hatching of young turtles is not synchronised to the phase of Meeka. Female turtles will come yira il the beaches at night to lay their eggs when the tides are highest, which occurs when Meeka wer Ngaangk (Sun) work together when Meeka is either new or full. Young turtles will emerge at any time during the night. They instinctively head for the brightest light, which will normally be Meeka over wardan (ocean). Nidja is why artificial bright lights (a form of light pollution) will betray them wer lead them to their death.
Eclipses[edit | edit source]
When Meeka is exactly in front of Ngaangk (the Sun), as seen from the Earth, the result is a Solar eclipse. When nidja happens the sky goes dark, stars can be seen, birds stop singing wer Ngaangk's corona (streamers) can be seen. Meeka exactly covers Ngaangk because although Ngaangk is 400 times wider than Meeka, Ngaangk is 400 times further away from the Earth than Meeka. N.B. the Earth is four times as wide as Meeka, so Ngaangk is 100 times wider than the Earth. Seeing a Solar eclipse is an amazing experience, but never look at Ngaangk or a Solar eclipse with your naked meeyal, and especially not with any instrument like a telescope or binoculars. If you look underneath a tree during a Solar eclipse, all the leaves overlapping each other may act as pinhole cameras so you may see multiple images of the eclipse on the ground.
When the Earth gets between Ngaangk wer Meeka the result is a Lunar eclipse, where Meeka goes dark. As the eclipse starts you can see the curve of the Earth's shadow falling il Meeka. The colour of Meeka during a Lunar eclipse is red because the only light reaching Meeka is red light coming through the Earth's atmosphere. It is red light because blue light is scattered more than red light in the atmosphere. This is why the sky is blue and we see Ngaangk as red at sunrise and sunset - all the blue light from Ngaank has been scattered as it travels through more of the atmosphere than when seen overhead. Nidja is not a Blood Moon, instead we should say the colour is copper, as opposed to the normal silver colour.
Weather[edit | edit source]
A big ring around the moon meant a big rain, a little line was just a little bit ... Sometimes the moon isn’t right in the middle of the ring, but to one side or the other. That means there’s wind coming. It takes a lot of explaining to understand it right. You gotta live a lot of years in the bush for that.
A Moon halo is a ring which forms around the Moon, usually in Winter, when light from the Moon is refracted through ice crystals in high altitude clouds (above 5 km) back down to the observer. It is sometimes called a 22° halo because its radius extends 22° across the sky; for comparison the Moon's diameter viewed from the Earth is just over 0.5°. The high altitude ice clouds are cirrus or cirrostratus clouds that often precede a large storm front. These clouds, as indicated by a Moon halo, are a sign that rain might be on the way in the next 12 to 24 hours, or as soon as 6–8 hours for a fast moving weather system. Note that if the Moon is new or temperatures are too high there will be no Moon halo but there may still be rain. As a sign of rain a Moon halo works in Noongar boodjar too.
Meeka Waarnk - Stories about the Moon[edit | edit source]
In many Aboriginal cultures (but certainly not all) Meeka is male wer Ngaangk (the Sun) is female, wer there are many different versions of stories, in different languages, in which the Moon-man falls ill (the waning Moon), lies dead for three nights (New Moon), wer then comes to life again il the third day (the waxing Moon).
Most people, from the Greeks to the Quechua Indians of Peru, designated the sun as male and the moon as female. Nearly all Australian Aboriginal peoples regarded the sun as female and the moon as male. The Yolngu people of the Northern Territory say Walu, the Sun-woman, lights a small fire each morning (the dawn). She paints herself with red and yellow wilgee (ochre), some of which spills onto the clouds to create the sunrise. She then lights a bark torch and carries it across the sky from east to west, creating the daylight. At the end of her journey, as she descends from the sky, some of her ochre falls on the clouds to create the sunset. She then puts out her torch, and through the night, travels underground to return to her camp. This underworld journey was important in the designation of the sun as female, her torch bringing warmth and fertility to the interior of the Earth, causing plants to grow.
Dingo makes us Human[edit | edit source]
Debbie Rose recorded nidja story from the Yarralin people. Keny day the Moon offered the dwert (dingo) a share in his law, offering the dwert immortality, but il his terms. The dwert refused to give yira his independence wer so was destined to die, passing il his law to his descendants, including people.
The lesson from nidja story is that nothing new comes into the Moon's world as nothing old goes out of it. Closed to the World, he lives for ever. His position is of total dominion over nothing. But dwert is open to life, sharing the finality of death wer the continuity of parts.
Places named after Meeka[edit | edit source]
Although 'Meeka' is part of the name of Meekatharra, a town in the Mid West region of Western Australia, it is widely accepted that 'Meekatharra' is a Yamatji Aboriginal word meaning "little water" or "place of little water" which seems appropriate given the low rainfall in the area.
See also[edit | edit source]
"Center of Mass". Physics experiments from Lynbrook High School, USA
Ngiyan waarnk[edit | edit source]
- Bernard Rooney. (2011). "The Nyoongar Legacy". Batchelor Press. ISBN 978 174131 232 4
- Carol Pettersen. "Yongka, Miyak : Kangaroo and Moon". Batchelor Press
- Mike Luciuk. How Bright is the Moon?: Variations in Albedo Affect the Moon's Brightness. Amateur Astronomers, Inc. Retrieved 23 May 2017
- Michelle Vick. "Why are there high tides during a Full Moon?". Ask an Astronomer. Retrieved 16 November 2019
- "What are spring and neap tides?". National Ocean Service. National Oceanic and Atmospheric Administration (NOAA). US Dept. of Commerce. Retrieved 23 June 2017
- Ben Collins. "How the sun, the moon, and a massive continental shelf create Australia's biggest tides in the Kimberley". ABC News. Retrieved 13 November 2019
- "Centre of Mass". COSMOS - The SAO Encyclopedia of Astronomy. Swinburne University. Retrieved 27 February 2019
- "Forces Of Nature With Brian Cox : Episode 2 Somewhere In Spacetime". ABC Television Documentary. 26 February 2019
- Carmelo Amalfi (2016). "Everything is written twice – on the ground and in the sky (part two)". National Indigenous Times. 6 May 2016. Retrieved 28 February 2018. See also part one, 18 February 2016
- "Crawford, Evelyn (1928–?)". Indigenous Australia. Retrieved 19 May 2019
- Crawford, Evelyn. (1993). "Over my tracks". Penguin
- Vekteris, Donna (2004). "Scholastic Atlas of Weather". Scholastic Inc. p. 14. ISBN 0-439-41902-6
- Australian Aboriginal Astronomy. CSIRO. Australia Telescope National Facility. Retrieved 3 November 2016
- Eugene Stockton. (1995). "The aboriginal gift: spirituality for a nation". Millenium Books. pp 78-79
- Meekatharra, WA. Aussie Towns, Retrieved 7 November 2018