0203 - 2025.06 Ionian Shadow

Io is intensely volcanically active due to tidal forces from Jupiter and its neighboring moons, with Sulfur and Sulfur dioxide abundant on the surface.

Lightly coloured from orbit, on the surface it’s much richer in colour. It is also much darker than this, the Sun being 770 million kilometres away, 5 times the distance of the Earth. 43 light minutes, if that’s how you like to measure it. Anyway, bright-ish.

Depending on where Io is on its circles around Jupiter, reflected light from the gas giant can colour the surface with a reddish, pinkish, yellowish glow. Jupiter is so large it’s a giant orb in the sky, the light is diffused and there are no sharp shadows.

This we knew well before we arrived on our photography tour last Jovian summer. I don’t know why they call it that, it’s not much different to the Jovian winter. Not like Italy, where we went the year before, after the Arctic got cancelled due to unseasonably warm weather and no ice. Mount Etna gave me a taste for volcanism and when Io came up I thought, why not.

Volcanoes on Io are more.dangerous than Mt Etna, and with Io being about as large as our Moon it is tidally distorted by Jupiter’s huge gravity with regular eruptions, Here’s a shot as we approached (confession: It’s from the brochure, the landing craft has no windows).

It looks dangerous from space, and on the surface more so.

We had a three hour window so the group voted on a landing spot, well away from any current activity. Don’t stray too far from the ship, you need to be able to see it to come back.

On landing we leapt out in all directions with our camera gear and started snapping like the pros. Some of the group I suspect were just here for the danger, their cameras were not very sophisticated.

With Moon-like gravity walking in a self contained space suit took a bit of getting used to; you cannot practice before you get there.

If you ask me which is my favourite photo, it’s this one. I’ve made it brighter than it actually was, but it has a zen like feel to it, a rock carefully placed on a field on stones, a light shadow adding depth of field, the sulphurous yellow both mono-chromatic and dangerous.

Just after I took the photo a rock about the same size landed where I had been standing. I never thought to look up, the camera was pointed down. Gave me a scare, so I thought I’d go back to the lander.

Another hour on the surface counted for nothing if a rock landed on me, who knows where from, in the light gravity it could have come from hundreds of kilometres away, perhaps ejected several days ago.

Three others in the group of ten were also back, telling similar stories of rocks landing nearby. With half an hour to go two more came back, and we started to hear the odd bang on the hull. Rocks were falling and the crew were looking nervous. They had radioed everyone to come back, but were getting no answers.

Fifteen minutes, ten minutes, five minutes. One. Ore more came back, looking flustered but manic, like they had cheated death. Zero minutes left, three missing, and no idea where they were.

The crew looked outside, it was raining rocks now, mostly small but enough to bruise, even in a suit. They could see no one scurrying back. Nothing on the radio. No search and rescue.

The three hour window wasn’t anything to do with orbits and gravity, it was air in the suits. We waited five more minutes then left, a rain of stones drumming on the hull.

Opposition happens every 13 months, and we were the last trip of the season.

Technique: #digital
Theme: #abstract #space
Highlight colour: #red #yellow

Series: #mini-sci-fi

Published on Medium 27 April 2026