Swakopmund at eleven on a winter night is a town with its back to the desert and its face to a cold black sea. The fog usually comes in. When it does not, the sky over the Namib is one of the darkest on earth, and a person standing in a garden can see a satellite go over as easily as a car go past.

On the night of 12 July 2008 a Swakopmund resident saw something that was not a satellite, and a week later sat down and told the American reporting centre NUFORC about it, which is the only reason the account survives.

It was, the writer said, a single bright light. It came in from over the sea and passed overhead heading south-east, inland, straight into the desert. It was moving fast: not as fast as a meteor, which is over in a second, but a good deal faster than any aeroplane. It made no sound at all. The whole thing took about two minutes, which is the interesting part, because two minutes is a long time to watch something that is faster than an aircraft and still have it in view.

That is the full report. It is short, plain and unadorned, and the writer offers no theory.

It did not arrive out of nowhere. Two months earlier the coast had been talking about lights. On a Sunday night in May 2008, according to The Namibian, several people in Usakos, the small railway town on the road inland, watched a round ball with a long tail come over very low and very fast, throw a great wash of light across the town, and disappear in the direction of Swakopmund. One couple described it as about the size of a beach ball. Nobody heard a sound. The paper noted, for the benefit of readers with long memories, that the Namib Times had run a similar story in August 1976, when Walvis Bay residents watched a strange glowing thing hang in the dawn sky until sunrise faded it out.

So a fast, silent light with a tail was reported inland in May, heading for the coast; and a fast, silent light was reported at the coast in July, heading inland. Whether these are one phenomenon, two, or the ordinary traffic of a sky that people had simply started watching more closely is not something a two-paragraph report can settle.

The easy explanations are all present. A bright fireball meteor on a shallow trajectory can last several seconds and leave a trail. A re-entering satellite or rocket body can last minutes, silent, and look like a slow bright light with a tail. A military or survey aircraft with landing lights on and engines drowned by surf could pass for either, at a stretch.

What is left is a person in a Swakopmund garden, a light out of the Atlantic, and the Namib swallowing it. The desert does not give much back.