Sunday Night Doppelgangers

“Somewhere in the world, we all have at least one person
who looks exactly like us.”

Melissa Doyle, Sunday Night, 18 August 2019

Last night the television program Sunday Night aired an interesting segment discussing the notion that each of us isn’t the only person on the planet who looks exactly like us – something she refers to as a doppelganger.  Doppelgangers are non-biologically related ‘twins’ of ourselves, though usually a doppelganger has a negative connotation – that the doppelganger is an evil or ghostly twin. Not in this case though.

Sunday Night’s segment on dopplegangers shows how confusing similar looking people in photos can be.  There are many fascinating pairs of doppelganger in this broadcast (which you can see using the 7Plus link in the reference below).  It is captivating to see how alike people can look.  It also seemed an ideal opportunity to demonstrate simple ways to distinguish between individuals in photos and work out if they are or are not the same person.  So what can you look for?

The ‘ears’ have it


‘Doppelgangers’ , Channel 7 ‘Sunday Night’ [1]

In this example, former President Barak Obama (right) seems to have a twin.  But in the briefest of glances an aware photo viewer can see that they are not the same person just by looking at the ears.  The man on the left has strongly attached earlobes, while Obama has completely free (unattached) earlobes.   Barring any accident or damage to the ear, ear shape is purely genetically dictated, and, since ears are complex and variable, ear shape is often different from person to person, and one of the easiest ways to rule out people in photos as matching  – it’s not the same person if their ears don’t match!

Face size matters

But what if the ears aren’t visible or don’t help you identify or rule out the identity of the person in the photo?  Look a bit more closely at the size of the face.  In these photos of John (left) and Neal (right), it is easy to see that John’s face is almost 10% longer than Neal’s face:


Doppelgangers John and Neal [1]

Shape and Colour

But what if they seem to have similar sized heads, or you can’t see their ears as in the photo as in the photos of Niamh and Karen below? There are so many ways in which their faces look similar, especially with matching makeup and hair. How could you tell them apart?


Doppelgangers Niamh and Karen [1]

Well, have a look at their eyes.  You’ll have to zoom in.


Doppelgangers Niamh and Karen – Details of eyes [1]

Look at the differences: the eye colours are a bit different as Karen (right) has greener eyes than Niamh (left), and Niamh’s eyes are shaped differently (more almond shaped and sharper in the inner corners). This is easy to see if you look carefully, even though their eyebrows and lashes have been made up to look identical. The trick is to focus on and compare individual parts and aspects of a person’s face, rather than to view it as a whole.

Hopefully these simple tips will help you next time you’re trying to decide if that woman in a family photo is your Aunt Judy or your Aunt Evelyn!

Doppelgangers, Sunday Night (18 August 2019) Accessed 19/8/19. Images used under ‘fair use’ provisions of copyright law.

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Born or Built? My excellent adventure with Questacon

Read in Spanishsmall_20190328_110956

This morning I attended the launch of Questacon’s Born or Built? exhibit.  I was invited because I feature in it! Yes, that’s right, along with a few others of my colleagues I am part of the exhibit, expressing my views as a computer scientist on aspects of robotics, from our relationship to them, through to serious ethical questions such as who is responsible for them and their actions.  Here I am!


This exhibit is the culmination of more than a year of extraordinary work by the Questacon team (Doug, Matt, Alex, Jason are the delightful people who engaged with us on the exhibit).  There are so many engaging activities in the exhibit, and of course robots.

small_20190328_10424520190328_104419Our Human Centred Computing team, led by Professor Tom Gedeon, met with the Questacon crew several times to offer input into some of their already admirably managed strategic directions, and one of our group, Sharifa Alghowinem, was a key contributor to the “Is this a face?” activity.

Last spring (that’s October here for my USA readers) Alex asked me if I would be willing to be filmed for this exhibit.

I gulped, applied makeup for the first time in 10 years, and went.  I’m so glad I did! It is extraordinary seeing yourself weighing in on important matters alongside notable peers, knowing that perhaps 500,000 people or more might listen to my views in the coming year.

The launch was a great affair, with Questacon Director Graham Durant speaking and the Australian Chief Scientist, Dr Alan Finkel formally opening the exhibit. Our College Dean, Professor Elanor Huntington, spoke at the event as well. An enormous group of children excitedly trying out all the activities and a quite active robot brought life (both human and robotic) to the exhibit.

When you get a chance, be sure to pay a visit to this exhibit.  It is super fun, mind-expanding, and profound.


p.s. I couldn’t resist adding this snap in as well.  I have never had my name in lights before!



All images by Sabrina Caldwell – taken with a Samsung cellphone.  Images cropped and resized for web use.  No other changes made. Photos can be used in accordance with Creative Commons Open Licence CC-BY-NC-ND.
Questacon exhibit home page

To see Dr Alan Finkel Chief Scientist tweets on this event:


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Ringing the New Year Resolutions: Photos ‘just because’

Photos ‘just because’

Sometimes I find myself not posting anything on this blog because I want to ensure I keep to my mission of “a public forum to explore the art, technology and social implications of photographs, photoart, and everything in between.” [1]  In doing so I cheat myself of the fun of sharing my photos ‘just because.’ So for 2019 I’ve decided to sprinkle in more photographs.

Dolichopodidae fly

Here’s the first example (only 86 hours into the New Year too; I’ve also decided to procrastinate less).  It is a tiny green metallic fly that obligingly scurried up and down the rail of our back deck for the time it took me to take over 4 dozen photos with my new Canon 58-100mm  macro lens.  Only about 7 of the 50 were in the ‘good’ range, and these are the 4 best of them. Not bad for my first try at macro photography!

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I tried to identify this fly, and tentatively identified it as being a ‘long-legged fly’ in the family of Dolichopodidae.  As tiny as he is (perhaps 5-6mm), he is a predator fly, who eats other insects even tinier than himself [2].

Certainly they have the required speed; here’s a photo of him taking off while I was clicking the shutter button!




All photos cropped for web-use only – no other changes.

[1]  About page

[2] Joseph M. Cicero, Matthew M. Adair, Robert C. Adair, Wayne B. Hunter, Pasco B. Avery, et. al.  (2017) Predatory Behavior of Long-Legged Flies (Diptera: Dolichopodidae) and Their Potential Negative Effects on the Parasitoid Biological Control Agent of the Asian Citrus Psyllid (Hemiptera: Liviidae)   Florida Entomologist, 100(2) : 485-487  Florida Entomological Society URL:  Accessed 4 January 2019.





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Daniel Boorstin (1914-2004)

“The greatest enemy of knowledge is not ignorance,
it is the illusion of knowledge.”

Daniel Boorstin [1,2]


[1]  Boorstin quote referenced by Godfrey Hodgson in “Prolific American social historian who charted the corrupting influence of advertising and spin on political life”
[2] Boorstin was the 12th Librarian of Congress for 12 years from 1975-1987.  Nice symmetry!

Daniel Boorstin said it in 1962…

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Posted by on December 18, 2018 in Quotes


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The eclipsed moon 28 July 2018


Total lunar eclipse

This weekend we here in Australia were treated to a total eclipse of the Moon, provided one could rouse oneself from sleep at 4:30am on a chilly winter morning  to view it.

The night was bright with the glow cast by the full Moon when I walked outside; the sky was wonderfully clear.   The shadow of the Earth was already taking the tiniest nibble from the top right corner of the Moon’s light.  The blinding glare of the full moon slowly gave way to the penumbral shadow, with details of the lunar landscape becoming visible, first in gray, then russet.

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Once the full face of the Moon was shadowed, and the Moon moved deep into the Earth’s umbral shadow, the colours of the Moon transformed into a sanguine sphere.


As the red-shadowed Moon sank in the West, it skimmed the tops of the Norfolk Island Pines, which added another layer of shadow (albeit an Earthly one), creating unexpected lacey patterns.

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Trailing the eclipsed Moon down the sky was Mars.  Close to the Earth at apogee, [1] Mars seemed larger than usual, while the Moon, whose orbit is at perigee, seemed smaller then usual.  The juxtaposition of these two extremes of orbital distance created an unusual proportionality.


As the Sun lightened the sky, the Moon and all its colourful glory began to fade into the horizon and the dawn. I stood there, with the Sun at my back and the Blood Moon before me, and felt connected to the Sun and the Moon and the Earth and Mars all at the same time: the Sun rounding the Earth was bringing an end to the enormous shadow cast by the Earth beneath my feet upon the Moon at the horizon with its companion Mars gliding silently behind.



All photos cropped and resized for web use.  No other changes made.

[1] Mars is 35.8 million miles (57.6 million kilometers) per NASA  Accessed 29 July 2018

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Posted by on July 29, 2018 in Astronomy


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