Inside, the exhibits include Pluto among the planets.

These include the Kuiper belt, with its well-known member Pluto, and other plutoids including Haumea and Makemake.

But scientists have long been uneasy about including Pluto, an icy ball smaller than our Moon, whose orbit is more eccentric than the others and tilts in a different plane.

That includes Saturn and Pluto.

This sub-category includes Pluto, Haumea, Makemake and Eris.

The model includes Pluto and has not been updated since Pluto was reclassified as a dwarf planet.

This includes Pluto, which shares its orbital neighbourhood with Kuiper belt objects such as the plutinos.

I pointed out that the mobile included Pluto.

The bodies are in the Kuiper Belt, that region beyond Neptune populated with perhaps 100,000 relatively small objects (including, by most classifications, Pluto, which is the largest of the lot).

This new class of objects, termed plutoids, would include Pluto, Eris and any other future trans-Neptunian dwarf planets, but excluded Ceres.