Orbiting Solar System - Thames & Kosmos

Build the Solar System. Wind It Up. Watch the Planets Move. — Thames Kosmos Orbiting Solar System

The Thames Kosmos Orbiting Solar System is a mechanical orrery — a wind-up model of the solar system where all eight planets orbit the sun simultaneously, each at its own speed. Children build the model from snap-together plastic parts, apply printed planet graphics to each planet, and discover how planetary gears drive the different orbital speeds — Mercury completing its orbit faster than Saturn, just as in the real solar system. No batteries required: a wind-up mechanism powers the orbits. The kit includes full-colour step-by-step assembly instructions and a built-in expansion slot for a potential Planet Nine. Ages 8+.

What Children Build and Learn

• ⚙️ Assemble a mechanical orrery from snap-together parts — the model goes together without glue or tools; the assembly process itself is the first learning stage, as children build the gear system that will drive the planetary motion before they see it work
• 🌍 Planetary gears in action — the wind-up mechanism drives a system of planetary gears that produces different orbital speeds for each planet; children can observe directly that Mercury orbits faster than Jupiter, and that the difference is produced by the gear ratios in the mechanism — not magic, but mathematics
• 🌠 Orbital mechanics and the solar system — as the model runs, children observe the order of the planets, their relative sizes, and their rates of revolution; the illustrated instructions include planetary facts for each planet, grounding the mechanical model in real astronomical knowledge
• 🎨 Planet graphics applied by hand — printed planet graphics are applied to each planet during assembly; the process of identifying and placing each planet’s markings reinforces the visual appearance and relative size of each planet in the solar system

How the Mechanism Works

The orrery is powered by a wind-up spring mechanism — no batteries, no electronics. Winding the mechanism stores mechanical energy in the spring, which is released gradually to drive the gear system. The gears are planetary gears — a specific gear arrangement where multiple gears orbit a central sun gear, producing different output speeds from a single input. This is the same principle used in automatic transmissions and many industrial machines. When the orrery runs, each planet’s orbital speed is determined by the gear ratio connecting it to the central drive — replicating the actual relative orbital periods of the planets in mechanical form.

Watch It in Action

Good to Know Before You Buy

• Recommended age: 8+
• Brand: Thames Kosmos
• Model type: Mechanical orrery (wind-up solar system model)
• Planets: All 8 planets included; printed planet graphics applied during assembly
• Power: Wind-up spring mechanism — no batteries required
• Assembly: Snap-together plastic parts; full-colour step-by-step illustrated instructions included
• Expansion: Built-in slot for a potential Planet Nine

Frequently Asked Questions

Does it need batteries?

No — the orrery is powered entirely by a wind-up spring mechanism. Wind the mechanism, set it down, and the planets orbit under their own stored mechanical energy. No batteries, no power cord, no charging required.

How difficult is the assembly?

The model uses snap-together plastic parts — no glue or tools required. The assembly is guided by full-colour step-by-step illustrated instructions. Children aged 8–10 will typically need some adult involvement for the gear assembly stages; children aged 10–14 can generally work through it independently. The assembly is a meaningful part of the learning experience — building the gear system before seeing it run is how children understand why it works.

What is the expansion slot for Planet Nine?

Astronomers have theorised the possible existence of a ninth planet in the outer solar system — sometimes called Planet Nine — based on gravitational anomalies observed in the orbits of trans-Neptunian objects. Thames Kosmos included a built-in expansion slot in the orrery so that if Planet Nine is ever confirmed and officially named, the model can be expanded to include it. It’s a thoughtful detail that acknowledges the model is a snapshot of current astronomical knowledge, not a fixed endpoint.

Is it a good gift?

Yes — it’s a standout gift for space-curious and mechanically-minded children aged 8 and up. The orrery sits at the intersection of astronomy and mechanical engineering: children who love space will want to build it to see the planets move; children who love how things work will be fascinated by the planetary gear system that drives it. A strong birthday or Christmas gift that functions as both a working model and a display piece once complete.