Some Stars Wobble

Claire Pendrigh, Some Stars Wobble, 2017, rocks and wire

This mobile is part of an exhibition of the same name, currently on show at Sawtooth ARI in Launceston. You can see all the artworks in the show here.

Some stars really do wobble. It’s one of the ways we can tell if a star has a planet orbiting it. Anything that is locked in an orbit with anything else, wobbles.

It’s easier to see If you look at two objects of similar mass that are orbiting each other, for instance, Pluto and its inner most moon Charon. With half the diameter and one-eighth the mass of Pluto, Charon is a very large moon. Its gravitational influence is big enough that both bodies spin around a point in space between them.

All orbital systems have this balance point; it’s called the “barycentre”. When a tiny planet orbits a massive star, the barycentre exists within the body of the star, so instead of making a discernable orbit, the star just appears to wobble.

The barycentre is nicely modelled in a mobile, as each side of each arm needs to be equally weighted. In Some Stars Wobble each mobile starts with two rocks on either end of a wire. I find the balance point, and add a loop and a swivel. Then I add another wire with a rock on the end. This time, the balance point has one rock on one side, and two on the other. To make the mobile hang flat, the balance point needs to be in the centre of mass between the two starting rocks, and the one new rock. The next level balances one rock against three rocks and the pattern continues.

In this mobile, I wanted to see just how complicated a balancing act between rocks in space might be. Imagine how many paths each rock could travel on its journey around this cluster – how many variations are possible.

Claire Pendrigh, Some Stars Wobble (detail), 2017, rocks and wire


A Sign in Space

Some Stars Wobble is on show at Sawtooth ARI Gallery in Launceston until 24 June.

In astronomy, a wobbling star indicates an orbiting object – the gravity of each object affecting the orbital path of the other.

For this body of work I decided to imagine what it would look like if I could trace my path through space, creating a line the followed me round and round; as the globe spins on its axis, as the Earth orbits the sun, as the solar system revolves, slowly, around the centre of the galaxy. I quickly discovered that this is a more complicated mental exercise than I had anticipated.

You can see all the artworks on my website at

I also thought that I might do a couple of posts about individual works in the show, here on my blog – starting with this series of tiny paintings, A Sign in Space.

Claire Pendrigh, A Sign in Space (series), 2017, oil on board

This series of paintings takes its title from a story by Italo Calvino, from his volume of “Cosmicomics”. Each story in this collection begins with some kind of scientific hypothesis, followed by a first person narrative recounted by the unpronounceable but irrepressible protagonist, Qfwfq.

In “A Sign in Space”, Qfwfq explains how he once decided to time how long it takes the Earth to complete one revolution of the Milky Way, by creating a sign in space. He leans out over the edge of the galaxy and finds a spot that is undisturbed by the whirling orbit of worlds within, and places his sign. Then he waits.

“So as the planets continued their revolutions, and the solar system went on in its own, I soon left the sign far behind me, separated from it by the endless fields of space. And I couldn’t help thinking about when I would come back and encounter it again, and how I would know it, and how happy it would make me, in that anonymous expanse, after I had spent a hundred thousand light-years without meeting anything familiar, nothing for hundreds of centuries, for thousands of millennia; I’d come back and there it would be in its place, just as I had left it, simple and bare, but with that unmistakable imprint, so to speak, that I had given it.” – Italo Calvino, “The Complete Cosmcomics; A Sign In Space”

In case you are wondering, it takes about 250 million years.

As our protagonist searches the outer reaches of the galaxy for his sign, he starts to worry. What if, after all this time, he can’t remember what his sign looks like? What if he passes it and doesn’t recognise it at all! I imagine his inner voice saying “Is it here? No, over here? I’m sure I passed by here before. It must be just around this corner.”

The need to place himself in the universe, with an identifying mark, becomes an obsession; one that I, and I’m sure many artists, can relate to. It’s the need to create a thing, that exists beyond yourself, that acts as a reference point, that you, and others, can look back on as proof of your existence in that space and that time. I was here.

The clusters of stars in this little series of paintings are based on real “globular clusters”. Globular clusters are spherical collections of stars, tightly bound together by gravity, found in the halos of galaxies (right near the edge). The stars in these clusters are extremely old, perhaps some of the first to have formed in the galaxy.

I like to imagine that these clusters could act as useful landmarks if you were searching the boundary of the galaxy for a sign you had left there. Unfortunately for Qfwfq, it is very hard to measure anything in a universe in which nothing stays still.

Some Stars Wobble

Some Stars Wobble opens 6pm Friday 2 June at Sawtooth ARI in Launceston, Tasmania.

Here on the Earth we are never still. Imagine drawing a line in space that traces your location as you go round and round, as the globe spins on its axis, as the Earth orbits the sun, as the solar system revolves, slowly, around the centre of the galaxy. The hanging mobiles, installations and paintings exhibited in Some Stars Wobble examine the complex balance of a shared existence in the universe.

There are also three other exciting exhibitions opening at Sawtooth ARI on 2 June, check their website for full details.

Opening 6pm Friday 2 June
Exhibition runs 1 June – 24 June

Sawtooth ARI
Level , 160 Cimitiere St
Launceston Tasmania

Gallery Hours 
Wednesday to Friday 12 noon – 5 pm
Saturday 10 am – 2 pm

I Missed It

Kate’s story takes place in the lovely little town of Nannup in WA.

This story is part of the Stargazers project for which I am collecting stories about stars. If you have a story that you would like to share with me then please get in touch!


A story to make you think twice about shooting stars! This story comes from my wonderful friend Kiri, and tells of a terrifying Dreamtime beast.

This animation is part of my ongoing project Stargazers. If you have a story about stars that you would like to contribute, please get in touch!


A story about travelling to new places, new planets, and what gets left behind.

This story is part of the Stargazers project for which I am collecting stories about stars. If you have a story and you would like to get involved then get in touch!

Binary System

Stargazers is a collection of stories about stars. This is the first story that has been given to me in the form of a poem.

The story looks at the binary star system SS Cygni in the constellation Cygnus. SS Cygni consists of two stars orbiting each other; one large, cool red dwarf, and one small, hot white dwarf. As they orbit each other the denser white dwarf pulls matter from the red dwarf, absorbing it into it’s self. This kind of stellar relationship is called a cataclysmic variable system, a suitable name because they often end dramatically.

I met Christine in Berlin and we got talking about binary stars. Some stars orbit each other peacefully at a respectful distance, some get too close and collide. Some are unbalanced, with one star dominating the other, stealing its matter and leaving it drained. In many ways, these systems make effective analogies of romantic relationships. Christine put words to a situation that I think many of us have experienced, and I now have a new-found empathy for SS Cygni.