In our universe, the one thing that never changes is the speed of light (~300,000 km/s). It’s the constant that tethers the real world to science fiction. It’s also what makes our situation on Earth so much different than that on other planets, and simultaneously the thing that unites us. Urwerk’s mores may be more tied to science, space, and even science fiction than any other watchmaker in the world, which is why it took it upon itself to create a watch that depicts the time it takes for the Sun’s light to reach the other planets in our solar system.
Based on the Earth-rotation-calculating UR-100V SpaceTime, the LightSpeed debuted in 2024 with a 54-layer ThinPly black carbon composite over a titanium inner structure. Well, the Swiss brand just swapped that hybrid case for a ceramic option that’s about as icy (and dark) as it is on Neptune.
From Earth to the Edge of the Solar System
Since founders Felix Baumgartner and Martin Frei launched Urwerk back in 1997 with their wandering hour satellite displays inspired by 17th-century papal night clocks, they’ve been asking a fairly simple question: Why stick to conventional hour and minute displays when you can map the entire cosmos onto a wrist? The UR-100V series, which arrived in 2020 as a more wearable evolution of their radical designs, answered that by incorporating “SpaceTime” complications that track Earth’s rotation and orbital distance. But the LightSpeed iteration pushed even further into the void.
Where the original SpaceTime models showed how far Earth travels along its equator and around the Sun, the LightSpeed tracks the propagation of photons from the Sun to each planet. Mercury sits at 3.2 minutes away. Earth at 8.3 minutes. Neptune, perched on the murky edge, demands 4.1 hours. A blue and green hand attached to one of the carousel arms indicates these planetary positions as it completes a full rotation every three hours, disappearing beneath the minutes track at Saturn and resurfacing at 9 o’clock.
Breaking Ceramic
The new ceramic composite case is a departure from both the original carbon fiber LightSpeed and traditional ceramic watchmaking in general. Baumgartner explains that sintered ceramics are notoriously hard but brittle and prone to shattering under impact. Urwerk’s solution integrates glass and carbon fibers within a polymer matrix, creating a material that maintains the aesthetic of ceramic without the fragility. The structure reveals subtle silver tones from the glass fibers when machined, while Frei notes that the white finish isn’t a single color but an optical effect that shifts from matte to softly luminescent depending on ambient light.
Measuring 43mm wide, 51.73mm long, and 14.55mm thick, the white ceramic case contrasts sharply with the deep black dial structure that hovers over the brand’s emblematic wandering hours mechanism. The back reveals a black DLC-treated titanium caseback with a sun-inspired rotor that powers the automatic UR 12.02 movement. That caliber, developed with Vaucher, beats at 28,800 vph and provides 48 hours of power reserve, regulated by Urwerk’s signature Windfänger air-resistance turbine system to prevent overwinding and stabilize the satellite display.
The Usual Urwerk Brilliance
Time is read via three revolving satellites bearing four numerals each, sweeping a 120-degree minute track. A red arrow-tipped indicator travels from 0 to 60, at which point the next satellite takes over. Hours and minutes are painted with Super-LumiNova. Once a satellite completes its journey across the minutes arc, it transforms into a cosmic marker for the planetary system display above.
Lastly, the watch comes with both black and white textured rubber straps included with a deployant buckle.
Spec Sheet
Model: UR-100V LightSpeed Ceramic
Case Material: Unbreakable white ceramic composite with silver fiberglass and carbon inserts; DLC-treated titanium caseback
Case Size: 43mm
Lug-to-Lug: 51.73mm
Case Thickness: 14.55mm
Movement: Vaucher Caliber UR 12.02 automatic with Urwerk Windfänger airscrew
Power Reserve: 48 hours
Functions: Satellite hours; minutes; time for sunlight to reach eight planets
Water Resistance: 50m
Lume: Super-LumiNova on hours and minutes
Strap: Textured rubber (black and white options included) with deployant buckle
Pricing & Availability
The UR-100V LightSpeed Ceramic is priced at CHF 67,000 (~$74,800 USD) excluding taxes, available now from Urwerk.
Recap
Urwerk UR-100V LightSpeed Ceramic
Urwerk just released a ceramic version of its UR-100V LightSpeed—the watch that tracks how long it takes sunlight to reach each planet in our solar system. The new unbreakable white ceramic composite case replaces last year’s black carbon fiber model while keeping all the cosmic complications that make this thing so innovative.
