Saturday, 8 February 2020

Poisoning the Vultures

One of the issues I became aware of in reading Birdlife’s (2018) report The State of the World's Birds, was the plight of vultures globally.  Here I quote Case Study 12 (pp 22-23)

Many vultures face imminent extinction across Africa, Asia and parts of Europe, where vulture populations are in freefall. The IUCN Red List charts a relentless decline over recent years. In 1994, 75% of the world’s 16 Old World vulture species were classified as Least Concern, meaning that they were not considered at risk of extinction. Only one species—Cape Vulture Gyps coprotheres—was thought to be globally threatened and was classified as Vulnerable. Today, just two species remain Least Concern. Of the rest, eight, half of all species, are classified as Critically Endangered and are at risk of imminent extinction; three are almost as imperilled and are classified as Endangered; and three are Near Threatened.
Populations in South Asia were the first to collapse, with declines of around 95% between 1993 and 2000. These were principally the result of acute poisoning linked to livestock carcases contaminated with the veterinary drug diclofenac. Worryingly, vultures are also disappearing across vast swathes of Africa. Over a period of just 30 years, populations of seven African vulture species have fallen by 80-97%. Here, the threats are more varied. They include deliberate persecution, such as by elephant poachers who kill vultures so that they do not draw attention to their illegal activities. Vultures are also killed for their body parts, which are traded for their supposed mystical properties. Other threats include habitat loss and degradation, decreasing food availability, fragmentation of remaining populations, human disturbance, collisions with wind turbines and powerlines, and electrocution on electricity infrastructure.

These disturbing statistics provide a place from which to discuss the complexities of wildlife conservation and convergent evolution.

The vultures are divided into two broad groups; the Old World (Europe, Asia, Africa) and the New World (American) Vultures. Even though they have a number of similar adaptations (see list below) they belong to different families of birds.  Old World Vultures belong to to Accipitridae (the raptors) and New World Vultures belong to the Cathartidae.  The similarity in morphology is an example of convergent evolution rather than descent.

Common adaptations in Old and New World Vultures (from Wink, 1995, Ogada etal, 2011)

  • bare heads and necks avoid pollution of feathers when feeding inside a carcass
  • strong hooked beaks with cutting edges to tear skin apart
  • long intestine and a stomach with strong acid are suitable for the digestion of rotten meat and bones and furthermore the latter kills microorganisms present in the putrified carrion 
  • the broad wings enable them to ride rising air currents with little energy expenditure while scanning large areas for carcasses
  • aerial searching also gives vultures a considerable advantage over terrestrial scavengers because the latter have limited feeding ranges, higher energy expenditures to locate carcasses, and comparatively poor visibility from the ground
  • the feet of vultures are more appropriate for movement on the ground than to catch prey (as in other raptors)
  • excellent eyesight which enables them to detect carcasses from great heights. (New World vultures also have a well developed sense of smell that is used for locating food in forested areas.)


Vultures play an important ecological role by consuming carcasses.  Outside of the oceans, vultures are the only known obligate scavengers (Ogada etal, 2011).Their strong stomach acid kills microorganisms in carcasses that may kill other scavengers or turn them into vectors for diseases such as anthrax, botulinum toxins, rabies, and hog cholera (World Atlas). Removal of vultures from an ecosystem increases the disease risk posed by these microorganisms.


Poisoning Grys vultures in Asia.


Following the cessation of its patent in the early 1990s, the NSAID (non-steroidal anti-inflammatory drug) diclofenac became widely available in India, including for veterinary use.  It is also used in humans for treatment of arthritis, although it is perhaps better known as Voltarin. The drug causes kidney failure in vultures of the Grys genus, (specifically severe, acute, renal tubular necrosis and resultant uric acid crystal deposition in the kidneys and other tissues.) In laboratory studies death occurs in less than sixty hours. What functions as medicine (albeit with complications) in mammals functions as a poison for the Grys genus vultures; a poison that resulted in a 95% reduction in the population of three species of Indian vulture in less than a decade.

White-backed and long-billed vultures were once regarded as probably the most common large raptors in the world but, in about a decade, and with a total loss estimated at tens of millions of individuals, these birds were listed as critically endangered. (Oaks, 2012)

Wikipedia has a page entitled the Indian Vulture Crisis which is worth a read. I have attempted to diagram the flow on effects of this species decline below. The emergent cost on human populations is enormous.



Poisoning African Vultures


Many species use vultures as a carcass detection services, e.g. hyenas and other vultures.  But for Africa’s big game poachers this environmental service also functions as a poacher detection service, therefore some poachers have been deliberately poisoning carcasses to prevent the vultures giving away their location.  A widely reported incident in 2019 resulted in the death of over 500 vultures from the poisoning of just three elephant carcasses in Botswana.

The 'Point of Wonder' for me in this is that it requires so few links to go from providing an anti-inflammatory drug to cows to leopard predation of humans, or from the same starting point to significant interruption of a religion. The intermediary step in this chain is a particular group of birds, the vultures.



Friday, 31 January 2020

Year of Birds ... #YOB2020

Detail of Satin Bowerbird from "After the Rain" by Susie Hamlet.

For a number of years now I have been running ‘themed years’, eg.  'Year of the Boat' (2013), 'Year of Geology'(2016).  Themed years started as an activity with my young son, who now thinks he has out-grown such things. So this year I am running with a theme of my own, “Year of Birds”.  Like the years with my son the years have challenges based on my age,


  • 53 bird sightings per week
  • collect 53 coins with birds on them
  • collect bird postage stamps from 53 nations
  • read a number of books about birds (53 seemed too ambitious). The first on that list is Tim Low’s (2014) Where Song Began.
  • write some bird poems


I am now in the second month of #YOB2020. I have managed the 53 bird sightings per week - with a little bit of organisation and discipline. I am using eBird to catalogue my sightings and really enjoying the experience (there is a blogpost coming about some insights from eBird). As I neared the end of the month I realised I had nearly observed 100 species in the month … an intentional drive south clicked me over the century mark. Ticking the species box is like finding a hidden treasure in an RPG (role playing game)... and I am observing a decline in my interest in online games :-). I will probably aim to have 100 species every month from now on.

I notice that birds are bringing me much joy. Stand out moments from this month have included leaning on the water tank while a grey butcherbird spent several minutes experimenting with a new tune; a morning walk when a male superb fairy wren scattered dew from the green grass it was pouncing on; and watching a group of seven little black cormorants working the edge of a pond like synchronised swimmers.

Last July, we camped near a billabong in the middle of the Dubbo Western Plains Zoo.  Among all the other waterbirds there was a black swan cygnet with its two adults.  Watching it interact with its parents, or pivot on its chest to stick its bum in the air was entrancing...  like falling in love. Here I was in a park filled with magnificent African animals - cheetah, rhino, hippos - yet I became charmed by a common, fluffy grey bird.  But that is the joy of birds, many of them are so accessible with a look out of the kitchen window, a wander in the local park. They have infiltrated our zeitgeist so much so that it would be hard to go to an art gallery and not find some bird reference.

For me at least there is a correlation between watching birds and good mental health practices. The scanning back and forth for the feathered treasures is like ‘forest bathing’. The use of multiple senses, where sight is often directed by hearing, and things in the periphery get brought into the centre, how a shadow can cue you look in a different place and find the shadow maker … these skills feel very similar to mindfulness exercises I sometimes use in the classroom. As my practice becomes more regular there is a satisfaction in linking sound to sight, and gaining the ability to see just a glimpse of a species in flight and identify it from the way it holds its wings, or the scoop and flap pattern of its flight. I think the phrase in mental health speak is ‘islands of competency’.

I am also finding islands of incompetency, a sound I do not recognise, a fleeting glimpse that does not trigger recognition, and I am treasuring the frustration … using it inspires me to dig a bit deeper. I am also using it to remind me of my students who are learning to count forwards and backwards, add simple numbers together, identify their letters and the sounds that go with them.  They too will transform their frustration into islands of competency.

Having a year creates community. Already a month in, people have shared postage stamps, sent photos or links to articles, lent me books to read. My wife is even enjoying a renaissance in her painting and bird themes are emerging there too.

So the ‘Point of Wonder’ is the birds themselves, but also the therapy and community that observing them has created.

Thursday, 2 January 2020

Spider diets

I recently visited the Queensland Museum's travelling exhibition, Spiders, which will be open until 4 May 2020.  I enjoyed seeing the spiders, but I also enjoyed seeing how science is communicated.  This dinner plate in particular I thought was fascinating.



The plate is divided into thirds, each third representing the diet of a spider with a different hunting strategy.

Top: Funnel Web Spider, Hadronyche sp., catches prey that lands on the ground.

Bottom Left: Huntsman Spider, Isopeda sp., catches prey that lands on or climbs up tree trunks, rock and walls.

Bottom Right: Golden Orb-weaving Spider, Nephila plumipes, catches flying prey.

As I thought about teaching food webs I thought that a simple graphic organiser like this could allow students to fine tune their understanding of a spider's place in the food web, with very clear linkage of diet to behaviour and micro-habitat. I like the exhibits method of using specimens, but this could be equally well achieved as a drawing or collage exercise.

Monday, 2 July 2018

Australian dinosaurs

This post was revised in Aug 2021.

In this post I present a list of the recognised species, together with a summary of how much bone we have for each species. It is surprising how little material we build our picture of Australia’s dinosaurs from! I will also provide a map to plot the location of the collection sites for these specimens, this map will also map the location of known dinosaur tracks (footprints).

Dinosaur List

Evidence for Australian dinosaurs is scarce and the diversity maintained in the fossil record very narrow.  There is clearly room for more to be discovered! Australia has 22 recognised species of dinosaurs identified from bone fossils, a further 9 species are imputed from dinosaur tracks.

The majority of the information in the following table is derived from the Australian Age of Dinosaurs website.

Species

Bone fragments known

Atlascopcosaurus loadsi

several jaw fragments

Australovenator wintonensis

~30% of a skeleton: arms and hands, legs and feet, several back and belly ribs, the paired front halves of the lower jaw, and several teeth.

Austrosaurus mckillopi

six vertebrate

Australotitan cooperensis

partial skeleton consisting of a partial left scapula, partial left and complete right humerus, right ulna, the right and left pubis and ischia and partial right and left femora.

Diamantinasaurus matildae

~30% of a skeleton, forelimbs, hind limb, shoulders, pelvis and several vertebrate and ribs. Partial skull.

Diluvicursor pickeringi

a partial right shin and foot, and a nearly complete tail

Fulgurotherium australe

a partial femur

Kakuru kujani

one opalised shin bone

Kunbarrasaurus ieversi

a near complete skeleton, armour  and stomach contents.

Leaellynasaura amicagraphica

a number of partial skeletons, but insufficient to piece together one animal.

Minmi paravertebra

eleven vertebra, fourteen ribs and a partial foot

Muttaburrasaurus langdoni

partial skeleton: skull, jaws, some vertebra, partial pelvis and limbs

Nanantius eos

shin bone

Ozraptor subotaii

shin bone

Qantassaurus intrepidus

three lower jaws with teeth

Rapator ornitholestoides

a bone from the palm of a hand

Rheotosaurus brownei

forty vertebra, partial pelvis, complete back leg

Savannasaurus elliottorum

20-25% of a skeleton: several vertebrae, ribs, parts of the shoulder and sternum, partial front limb bones including a complete right front foot, most of the pelvic girdle, an ankle bone and one bone from the hind foot.

Serendipaceratops arthurcclarkei

an ulna (forearm bone)

Timimus hermani

two thigh bones

Walgettosuchus woodwardi

single vertebra from the tail

Wintonotitan wattsi

several vertebrae, rib fragments, chevrons, partial shoulders, forelimb, and hip bones.


Observations on names:
  • two clearly recognise the sponsors who assisted with the digs, i.e. Atlascopcosaurus recognising the mining company Atlas Copco, and Qantassaurus recognising the airline QANTAS.
  • Two have aboriginal rather than Latin names, Kakuru kujani, 'kakuru' is the name for the rainbow serpent, in the 'kujani' language.  Kunbarrasaurus, 'kunbarra' is a local aborignal word for 'shield'.
  • One of them is named after the science fiction writer Arthur C. Clarke, Serendipaceratops arthurcclarkei.
  • One of them is named after a character in Conan the Barbarian, Ozraptor subotaii.

Postage Stamps


Stamp collectors may recall two handsome mini-sheets that were released to celebrate Australian dinosaurs.  The first, printed in 1993, was produced by Peter Trusler an Australian artist who specialised in paleontological topics.  The second, printed in 2013, inspired by the first, was produced by New York artist James Gurney.  Gurney produced a video about his artistic practice during this project which is worth viewing. 

Peter Trusler's mini-sheet from 1993.
Image source

Jame Gurney's mini-sheet from 2013.
Image source

Notice that Timimus is depicted in both, but understanding about the taxonomy of the species had changed in the intervening years.  This has seen Timimus move from being considered an ostrich mimic to something closer to a Tyranosaur, this reflected in how this species is depicted. Ironically it is the Tyranosaur not the ostrich mimic that has the feathers.


Comparison of depictions of Timimus, separated by 20 years.
Image source

You may have noticed that three of the names in the stamps are not in the list above, Koolosuchus and Ornithocheirus do not meet the criteria for a dinosaur, the stamps do not indicate that they were considered dinosaurs merely that they were alive at the time.  

The record of an Allosaurus has also undergone revision. In 1993 it was thought that an Allosaurus had been found in Australia on the basis of one ankle bone. Allosaurus is an American dinosaur. That identification has now been revised, and Allosaurus is no longer recorded for Australia.


A Dinosaur Map


Below is a screen shot from my Google My Maps 'Australian Dinosaurs', within the map if you click on the location it will show the species identified at that site.  The geolocating is very coarse and does not represent the actual location of a certain dig (You will need to click on the link above not the picture).

Some dinosaur track sites are Australian tourist attractions. Two in particular the Dinosaur Stampede National Monument at Lark Quarry, near Winton, Queensland, and the Dinosaur Coast, near Broome, in Western Australia, are of particular note.





Track marks and dinosaurs are colour coded by age, Yellow = Cretaceous, Orange = Jurassic and Triassic = Red.

Sunday, 10 June 2018

The Blaschka sea life models

Soft bodied animals are very difficult to preserve, which in part is why we have so few records of them in fossils.  Even in a preserving solution like formalin they sag and lose their colour.  What in life would have been an intricate interplay of shape and colour becomes an amorphous blob.  So it was with a sense of with wonder that I encountered the Blaschka sea life models, models of soft bodied marine life made from glass.  They went beyond giving a suggestion of an animal, to being art pieces of such precision they could be used to teach people how to differentiate one species from another.  In the case of the radiolarian models enabling otherwise microscopic organisms and details to be visible without magnification. 

The octopus below is just one of hundreds of marine organisms modelled in glass by the Blaschkas 150 years ago, and I imagine that for a person who knew their octopi this is easily identifiable to the species level.

A Blaschka octopus, probably Octopus vulgaris,  part of the Harvard collection.  Photo from the Boston Globe
https://www.bostonglobe.com/arts/theater-art/2014/07/26/blaschka-sea-creatures-exhibit-opens-harvard/G5zUYHgt4Inqlj8pIjuh8L/story.html

In this blog post I provide an annotated list of websites where my readers can explore Blaschka models for themselves. Consider this a belated contribution to World Oceans Day (7 June). If you find yourself falling down the rabbit hole of wonder at these models I am sure you have the skills to find your your way either back out or deeper in.

The makers

The father and son partnership of Rudolph and Leopold Blaschka made over 10,000 models spanning 700 species in the period 1863 to 1890 (Sarakas, 2016).

Leopold and Rudolph represent a long lineage of glass makers, dating back to Venetian glassmakers in the 15th Century (University of Dublin).

Their craft was not passed to another generation, and to this day some of the Blaschka techniques and skills have not be replicated, which I imagine is problematic for restorers.

The Blaschkas based some of their craft initially on drawings. Of particular note as sources of information for their models were the following works.  As they became more renowned they started to use actual specimens for their work.

  • Philip Henry Gosse (1853) A Naturalist’s Rambles on the Devonshire Coast.  A digital copy is available at the Internet Archive.
  • George Brettingham Sowerby (1857) A Popular History of the Aquarium of Marine and Fresh-Water Animals and Plants. A digital copy is available at the Internet Archive.
  • Philip Henry Gosse (1860) Actinologia Britannica: a history of the British sea anemones and corals. A digital copy of this work is available at the Internet Archive.
  • The works of Ernest Haeckel.  Including Radiolaria (1862) and others, many of these works are also available online.

Blaschka glass model photographed by Guido Mocafico (top) and watercolour of the same.
The creature is a blue dragon, Glaucus atlanticus, a small sea slug that feeds on jellyfish.  I think it was encountering a picture of a Blaschka model of one of these that started my fascination with the Blaschkas.  As a child I regularly encountered these blue dragons washed up on Queensland beaches.
Source: https://www.ucpress.edu/blog/21026/a-sea-of-glass-and-the-blaschkas-fragile-legacy/

The Blaschkas' skill is so exquisite that even photographs of their work can fetch high prices.  Of particular note is the work of Guido Mocafico.  If you compare Guido's "medusa" (jellyfish) photographs to his Blaschkas you will appreciate his clear fascination with the later [be warned if you appreciate photography you may get a bit lost on this site!].

The Collections

Australian Museum (Sydney)

The Australian Museum website has images of 43 anemone specimens.  The Australian Museum ordered their Blaschkas in 1879, displayed them until 1941, then moved them to museum archives.

This image of the sea anemone, Hormathia margarita, looks like belongs in a swanky cake shop.
Image:  Australian Museum. 


Cornell (US)

Cornell has a significant collection of Blaschkas.  Their online archive has images of 250 specimens, is well catalogued with both the scientific name and the Blaschka number of the model.

One of the locations within Cornell for the Blaschka models is the Corning Museum of Glass (CMOG). This article on Atlas Obscura  provides some details of CMOG's curation of the Blaschkas.

Cornell was also involved with the production of a film Fragile Legacy, which is available for download via Vimeo on demand.  The film focuses on both ocean conservation and the Blaschkas. There is a catalogue of an exhibition which accompanied the launch of the film. The online catalogue provides images of numerous models, some 3D viewable models,  and images of the paints and tools used to create them.  It also has a map detailing some of the locations for Blaschka collections and associated items (like sales catalogues).

Harvard (US)

Harvard has a collection of 430 Blaschka invertebrate models, with 60 on permanent display.  These form the basis of a recent book entitled Sea Creatures in Glass.  The website also has access to 3D scans of some models.  Harvard also houses the Blaschka glass flowers exhibit.

Natural History Museum (London, UK)

The NHM has 185 Blaschkas, they appear regularly in the institutions blog roll, enter Blaschka into the search panel to find these.  I recommend this Youtube video (6:22 minutes) which shows some of the NHM models and explains their conservation.

Radiolarians are a feature of the NHM Blaschka collection.  Much of the work brought the micro into the macro and would have been based on Heackel's work.  This is a specimen of Actinomma asterocantium.  Image: NHM.

University of Dublin (Ireland)

Has a collection of 400 Blaschkas.  There are very few photographs on their website and a number of the links to other collections no longer work.  However the text on the Blaschkas is informative.

Museum of Wales

Museum of Wales has a number of Blaschkas.  They appear in the following posts. [NB: I found the site was misbehaving on blog writing day].

Model of the jellyfish Physalia arethusa, a feature in 'repairing the irreplaceable article.
Image: Museum of Wales.

Saturday, 2 June 2018

Astronomical names it's all Greek to me



I have recently finished reading Stephen Fry's (2017), Mythos: a retelling of the Myths of Ancient Greece (Penguin). The reading is easy and fun, with humour typical of Fry's stage presence and other writing.  To read Mythos was also to read a context for the nomenclature of space, a who's-who of astronomical objects and some present day constellations.  I place on my list of recommended reading for astronomy bluffs, though given its placement in a fiction genre it frustratingly lacks both a table of contents and an index.  Mythos is also a treasury for etymologically curious people as clearly Fry loves to understand words.  Read his footnotes, some gems in there also.

To prove the point that space is full of Greek names, I have compiled this summary from a more exhaustive list on the International Astronomical Unions site.  Also worth reading their guide to naming conventions, which describes how decisions are made about how things are named, including planetary features like craters.

The Planets


In English speaking astronomy the eight solar system planets bear the names of Roman gods (Uranus exempted), but is also worth observing that there is correspondence to Greek gods and therefore we could consider that the Greek god is also being referenced.  I have included Pluto and Ceres in the list, because even though they are no longer considered planets, they fit the pattern being described.  Table mostly derived from the Mythology for Dummies Cheat Sheet.  Ceres was discovered in 1801, labelled as planet and 'demoted' to an asteroids in the 1850s.


RomanGreekDescription
MercuryHermesMessenger of the gods
VenusAphroditeGoddess of love
GaeaGaiaEarth
MarsAresGod of War
CeresDemeterGoddess of the harvest
JupiterZeusKing of Gods
SaturnCronosFather of Zeus, Son of Uranus
CaelusUranusGod of the Sky
NeptunePosidionGod of the Sea
PlutoHadesGod of the Underworld

The Moons of the Solar System


The list that follows provides the name of the planet with the name of its moons as indented dot points, only Greek names make it to the list. Roman numerals follow the IAU convention and indicate the planet's orbit order (I assume). Once again I have included Pluto because it fits the pattern.

Earth

  • The moon, Selene in Greek, hence the prefix Selenic for 'lunar' features.

Mars

  • Phobos (I) - one of the horses that drew Ares chariot (translated 'fear').
  • Demios (II) - one of the horses that drew Ares chariot (translated 'flight').

Asteroids

  • Eros - god of love
  • Ida - a nymph who raised Zeus
  • Dactyl (I) - mythological beings who assisted Ida
  • Kalliope -
  • Linus (I) - 

Jupiter

  • Io (I) - one of Zeus' lovers. Changed into a cow to protect her from Hera.
  • Europa (II) - one of Zeus' lovers.
  • Ganymede (III) - one of Zeus' lovers.
  • Callisto (IV) - one of Zeus' lovers. Changed into a bear to protect from Hera.
  • Amalthea (V) - naiad who nursed Zeus.
  • Himalia (VI) - one of Zeus' lovers.
  • Elara (VII) - one of Zeus' lovers.
  • Pasiphae (VIII) - one of Zeus' lovers. Wife of Minos.
  • Sinope (IX) - Zeus failed to seduce this character.
  • Lysithea (X) - child of Zeus.
  • Carme (XI) - one of Zeus' lovers.
  • Ananke (XII) - one of Zeus' lovers.
  • Leda (XIII) - one of Zeus' lovers.
  • Thebe (XIV) - one of Zeus' lovers.
  • Adrastea (XV) - cared for the infant Zeus.
  • Metis (XVI) - one of Zeus' lovers, mother of Athena.
  • Callirrhoe (XVII) - step child of Zeus.
  • Themisto (XVIII)  - one of Zeus' lovers.
  • Megaclite (XIX)  - one of Zeus' lovers.
  • Taygete (XX)  - one of Zeus' lovers.
  • Chaldene (XXI)  - one of Zeus' lovers.
  • Harpalyke (XXII) -  one of Zeus' lovers.
  • Kalyke (XXIII)  - one of Zeus' lovers.
  • Iocaste (XXIV)  - one of Zeus' lovers.
  • Erinomee (XXV)  - one of Zeus' lovers.
  • Isonoe (XXVI)  - one of Zeus' lovers.
  • Praxidike (XXVII) - one of Zeus' lovers.
  • Autonoe (XXVIII)  - one of Zeus' lovers.
  • Thyone (XXIX)  - one of Zeus' lovers.
  • Hermippe (XXX) - one of Zeus' lovers.
  • Aitne (XXXI)  - one of Zeus' lovers.
  • Euanthe (XXXIII)  - one of Zeus' lovers.
  • Euporie (XXXIV) - daughter of Zeus.
  • Orthosie (XXXV) - daughter of Zeus.
  • Sponde (XXXVI) - daughter of Zeus.
  • Kale (XXXVII) - daughter of Zeus.
  • Pasithee (XXXVIII) - daughter of Zeus.
  • Hegemone (XXXIX) - daughter of Zeus.
  • Mneme (XL) - daughter of Zeus.
  • Aoede (XLI) - daughter of Zeus.
  • Thelxinoe (XLII) - daughter of Zeus.
  • Arche (XLIII) - daughter of Zeus.
  • Kallichore (XLIV) - daughter of Zeus.
  • Helike (XLV) - daughter of Zeus.
  • Carpo (XLVI) - daughter of Zeus.
  • Eukelade (XLVII) - daughter of Zeus.
  • Cyllene (XLVIII) - daughter of Zeus.
  • Kore (XLIX) - daughter of Zeus.
  • Herse (L) - daughter of Zeus.
  • Dia (LIII) - one of Zeus' lovers.

Saturn

  • Mimas (I) - a Titan
  • Enceladus (II) - a Titan
  • Tethys (III)  - a Titan
  • Dione (IV) - Zeus had sex with this person.
  • Rhea (V) - a Titaness, mother of Zeus.
  • Titan (VI) - a Titan.
  • Hyperion (VII) - a Titan.
  • Iapetus (VIII) - a Titans
  • Pheobe (IX) - a Titaness.
|
  • Epimetheus (XI) - son of Iapetus.
  • Helene (XII) - granddaughter of Kronos. Her beauty triggered the Trojan War.
  • Telesto (XIII) - daughter of Oceanus and Tethys.
  • Calypso (XIV) - daughter of Oceanus and Tethys.
  • Atlas (XV) - a Titan.
  • Prometheus (XVI) - son of Iapetus.
  • Pandora (XVII) - made from clay at the request of Zeus.
  • Pan (XVIII) - god of pastoralism.
|
  • Methone (XXXII) - daughter of the giant Alkyoneos.
  • Pallene (XXXIII) - daughter of the giant Alkyoneos.
  • Polydeuces (XXXIV) - son of Zeus and Leda.
  • Daphnis (XXXV) - son of Hermes, brother of Pan.
|
  • Anthe (XLIX) - daughter of the giant Alkyoneos.
|
  • Aegaeon (LIII) - hundred armed giant.

Uranus

  • Nothing here, all moons named after characters in Pope's "Rape of the Lock" or characters from Shakespearean plays.

Neptune

  • Triton (I) - sea god, son of Poseidon and Amphitrite.
  • Nereid (II) - collective term for the daughters of Nereus and Doris ... Poseidon's attendants.
  • Naiad (III) - collective term for water nymphs.
  • Thalassa (IV) - sea goddess.  Mother of Aphrodite or Telchines.
  • Despina (V) - daughter of Poseidon and Demeter.
  • Galatea (VI) - a nereid.
  • Larissa (VII) - one of Poseidon's lovers.
  • Proteus (VIII) - a sea god, son of Oceanus and Tethys.
  • Halimede (IX) - a nereid.
  • Psamathe (X) - a nereid.
  • Sao (XI) - a nereid.
  • Laomedeia (XII) - a nereid.
  • Neso (XIII) - a nereid.

Pluto

  • Charon (I) - the boatman who ferried souls across the river Styx.
  • Nix (II) - goddess of dark and night, mother of Charon.
  • Hydra (III) - monster of the underworld.
  • Kerberos (IV) - nine-headed guard dog of the underworld.
  • Styx (V) - goddess of the underworld.

Dwarf Planets

  • Eris - goddess of discord and strife.
  • Dsynomia (I) - daughter of Eris, spirit of lawlessness.
Most of the Solar system's moons (there are more than 180 of them) have been discovered in the last 30 years.  The fact that so many of them bear names tied to Greek mythology is not therefore a recognition of ancient knowledge but rather a scientific desire to have systems of naming for such objects.  I for one find such a name more interesting than an alpha-numeric code, which most of these objects would have had prior to gaining their Greek name.

All this amazing cast of characters, and I have not yet started on the stars, or the constellations that include them.  Nor the names of features, like craters, on the astronomical objects listed.  Both areas are rich sources for links to further Greek mythology.

Tuesday, 12 December 2017

Rescaling the Solar System

The task of this post is to present two resources that introduce students to a basic understanding of the Solar System, along with some ideas about how these resources could be utilised.  It contributes to the Year 5 Australian Curriculum (but is more widely useful) ...
The Earth is part of a system of planets orbiting around a star (the sun) (1) identifying the planets of the solar system and comparing how long they take to orbit the sun (2) modelling the relative size of and distance between Earth, other planets in the solar system and the sun (3) recognising the role of the sun as a provider of energy for the Earth. (ACSSU078)
A previously released resource, Solar System Happy Families (see previous post), may also be of interest.

‘The Hitchhikers Guide to the Galaxy’ says it beautifully
“Space," it says, "is big. Really big. You just won't believe how vastly, hugely, mind bogglingly big it is. I mean, you may think it's a long way down the road to the chemist's, but that's just peanuts to space, listen...”
But to grasp ‘how big’ requires us to play around with the scale of the objects in a system.  Because of the difference in magnitude of the planet’s size and the distances between them it is not possible to represent both in a diagram.  At best we need to use two scales, one for the planetary size and another for the distances between the planets.  Certainly any representation of the orbits of the planets that would fit in a book would have planets so infinitesimal as to be invisible if distance and size were the same scale.

To grasp both we can conceptualise the Solar System with scaled objects and then place them in the landscape, either in reality (using a walk or a drive) or imaginatively (using maps).  Such representations are a common science outreach tool.  For example, the Solar System Drive in NSW, is scaled so that the 37m dome of the Siding Springs observatory represents the sun.

The Neptune station on the Solar System Drive, NSW. A pull over point on the Newell Highway.

Deeper learning can be achieved if students work on representations based on their own imagining. Solar System Rescaler (link here) provides an online rescaling tool to achieve this.  Based on simple formulas, first written in Excel and now transferred to Google Sheets, the spreadsheet enables a user to enter the dimensions of an everyday object to represent one object in the solar system, for example, what if the Earth were the size of a marble?  The spreadsheet then calculates a scaling factor and rescales both the orbits and the object sizes of a number of nominated objects in the solar system.  Instructions and explanation of the formulas is provided in the supporting documentation linked to via the rescaler.

A couple of examples.

In my backyard I created a representation of the Solar System rescaled so that a 400mm bird bath could represent the sun.  Only the four inner rocky planets would fit inside my yard and I represented these with holes drilled into aluminium plates that I attached to the fence, thus the Earth was 3.6 mm in diameter and 42.8 m away from the bird bath. The furthest planet, Neptune, was 1.29 km away.  Amazingly at this scale, the nearest star, Alpha Proxima at 4 light years away would be represented as being 10,800 km distant from my bird bath.   And what is between us and our nearest star? Well… billions of tiny objects which are so small that on average we could consider the space as ‘empty’.  That is our nearest star! The furthest object visible to the unaided eye is 2.25 million light years away. Space is big!


Aluminium plate for Mars, planet size represented by the hole with orbit of the two moons, Phobos and Deimos, represented by scribed circles.

Lego produced planets for some of their Star Wars models and I like to play around with these in the classroom.  In part because Lego is a familiar object, and for many students is immediately associated with creativity, but also because it is big enough to allow for tactile engagement.


Lego planet element and Lego boulder, with an Australian fifty cent piece for scale.

I start with these two objects a Lego planet, representing earth, and a Lego boulder, representing the moon (the scaling is about right). Invite students to hold the two objects, estimating what they consider to be the correct distance apart to represent the moon’s orbit.  Most will nominate a distance under 600mm.  The true distance is closer to 2.6m.  Below is the output from the rescaler.


Screen grab from the Rescaler.  Note the entry of the planet’s size, 86 mm, in the rescaler column.  Also note that the object type filter is active and displays only planets, the sun and the moon.

It is then possible to ask the question, what if we scaled the Solar System so that the sun was the size of the Lego planet? Segueing from this I produced a postcard resource (link here) which encourages students to decorate a postcard for a Lego representation of the Solar System, asking the question, how big would the Solar System be if any planet were scaled to the size of the Lego element?

Students then research various metrics for the planets, daylength, orbital period, max and min temperature, number of satellites etc, etc.  This information could then be recorded on the card.

Postcard for Jupiter. On the left is a blank lego planet (full size) for students to decorate. On the right the planets name, planetary symbol and a 1:1,000,000,000 dot to represent the planet at that scale.


Suggested extension activities for the postcards include.

a) Having conducted the research into another planet, students could write an imaginative piece pretending they were on that planet and writing a postcard to a friend either on Earth or on another planet in the Solar System.

b) When Lego released the planet element, it was Star Wars themed.  Students could design a Lego build to go inside the planet element, together with an appropriate mini figure that could represent someone who may have been of influence in learning about the planet, or perhaps the god after whom the planet is named.

c) The postcards contain a scaled version of the Solar system (1 is to 1 billion) in the right panel of the card.  Students could lay these out around the school grounds and perhaps share their learning with another class who is not working on the unit.

If you invent other things to do with this please share - use the comments section below.