The arrow of time. One of the greatest mysteries of our universe. Why can we move forward in time, but never back? If you add milk to your coffee, it gradually blends, but the reverse – separating into milk and black coffee – never happens. Perhaps that's why time marches relentlessly forwards, and why we can never go back a few years to meet our younger self...
But today's time travellers exist: they are people who are constantly crossing time zones and so have to keep track of local time, and the time back home. This is where watches with a second time zone are very useful. Take, for example, the Ingenieur Dual Time Titanium, part of the Formula One-inspired collection presented at Baselworld in March 2013. While local time is shown on the conventional hour and minute hands, an extra hand indicates a second time zone on the outer 24-hour ring. This is divided into day and night halves, so that there is less risk of phoning a business partner in the early hours of the night by mistake. The racing aesthetic is heightened by the modern numerals, the titanium case and dial, and the rubber strap and coatings of crown and push-buttons.
Rolex has a long and prestigious tradition in watches for travellers. When Pan American World Airways made its first non-stop flight between New York and Moscow in 1959, the crew used an Oyster Perpetual GMT-Master chronometer, providing readings of two different time zones simultaneously. In 2013, Rolex introduced a new version in 904L steel, with a rotatable bezel divided into two halves, in blue and black ceramic, representing day and night. The Cerachrom bezel is virtually scratchproof, and the 24-hour graduations are coated with a thin layer of PVD platinum. The self-winding mechanical movement is guaranteed perfect protection by the 40-millimetre Oyster case, waterproof to 100 metres, and a sapphire crystal with a Cyclops lens at 3 o'clock for easy date reading. The 24-hour hand for the second time zone is blue, and can be set quickly, independently of the other indications. A tough and distinctive appearance in the unmistakable Rolex style.
The Grande Reverso Ultra Thin Duoface by Jaeger-LeCoultre represents a totally different approach to displaying a second time zone. The Reverso, a design dating back to 1931 and originally created so that the watch case could be flipped over to provide protection for dial and glass during polo matches, has proved to be an extraordinarily versatile innovation. In 2013, this new ultra-thin version of the model was presented, with a single movement driving two separate dials. One face is very similar to the original 1931 Art Deco-inspired version, with just the 'Reverso' logo and a small seconds subdial. The other face is very different, with black dial and clous de Paris guilloché, Jaeger-LeCoultre logo, and day-night indicator. The total thickness is just 9.14 millimetres. The button on the side of the case makes it easy to adjust the second time zone hour by hour.
Omega's Seamaster Aqua Terra GMT was presented in 2012, the first of the brand's co-axial movements to have the GMT complication, with a diamond-polished red arrow that indicates the second time zone. A watch of this type has a second function: finding compass north. When the watch is held parallel to the ground with its hour hand pointing towards the sun, the GMT hand (adjusted to the same local time) indicates north in the northern hemisphere. The distinctive finish of this watch includes a sapphire caseback providing a view of the lovely co-axial movement, and the characteristic teak-pattern dial, reminiscent of classic yachts.
In some situations, a type of time reversal becomes crucially important, as in a regatta, when an initial sound signal marks the start of a countdown to the moment that you can cross the starting line. The Corum Admiral's Cup AC-One 45 Regatta deals with this very efficiently, with the countdown minutes shown in a window at 3 o'clock. When the countdown has reached zero and the boat can cross the start line, the countdown gear train is blocked, while the chronograph continues running, but in the opposite direction, forward in time, to record up to 12 hours of racing. A superb timepiece, with the characteristic dodecagonal case in titanium with black PVD coating. Enjoy your travels in time, whether in the air or on the sea!