Short answers, pulled from the story.
The Sweden Solar System is the world's largest permanent scale model of the Solar System, spread across Sweden from Stockholm to Kiruna above the Arctic Circle. It uses a scale of 1:20,000,000, so one metre of ground represents 20,000 kilometres in space.
Avicii Arena in Stockholm, also widely known as Globen, represents the Sun. It is the largest hemispherical building in the world, 110 metres in diameter, and at the model's scale it represents the Sun including its corona.
The Sweden Solar System was started by Nils Brenning, a professor at the Royal Institute of Technology in Stockholm, and Gösta Gahm, a professor at Stockholm University.
The model extends approximately 950 kilometres from Stockholm. The outermost marker is a foundation plate at the Institute of Space Physics in Kiruna, above the Arctic Circle, representing the Termination Shock at the edge of the heliosphere.
Pluto and its moon Charon are placed near the Dellen lakes in Delsbo, about 300 kilometres from the Globe. The lakes are thought to have formed from a meteorite impact 90 million years ago, and the sculptures stand on pillars made of dellenite, a rare mineral created by that same impact.
The golden Eris model at Umeå Arts Campus, made by artist Theresa Berg and inaugurated on the 6th of December 2007, is inspired by the mythological Eris who provoked conflict among three Greek goddesses with a golden apple inscribed kallistē. The dwarf planet Eris was named for that myth because its discovery sparked the debate that led to Pluto's reclassification.