Physicists at the National Institute of Standards and Technology have precisely calculated how time flows differently on Mars compared to Earth, showing clocks there tick 477 microseconds faster per day on average. This variation, influenced by gravity and orbits, fluctuates by up to 226 microseconds throughout the Martian year. The findings are vital for future navigation and communication in Mars exploration.
Albert Einstein's theory of relativity predicts that time passes at different rates depending on gravitational fields and motion. Applying this to Mars, researchers Bijunath Patla and Neil Ashby at NIST have quantified the discrepancy for the first time. Their study, published in December 2025 in The Astronomical Journal, reveals that a clock on Mars' surface would run faster than one on Earth due to the red planet's weaker gravity—about one-fifth of Earth's—and its eccentric orbit around the Sun.
The average daily difference stands at 477 microseconds, but it varies significantly. Mars' elongated path and influences from the Sun, Earth, Moon, and other bodies cause shifts of up to 226 microseconds over its 687-Earth-day year. For comparison, time on the Moon advances a more consistent 56 microseconds per day faster than on Earth. Patla noted the complexity: "A three-body problem is extremely complicated. Now we're dealing with four: the Sun, Earth, the Moon and Mars. The heavy lifting was more challenging than I initially thought."
These microsecond gaps may seem trivial, but they are critical for technologies like GPS equivalents on Mars. Current Earth-Mars communications already face delays of 4 to 24 minutes, akin to pre-telegraph eras. Synchronized timing could enable a solar-system-wide network. "If you get synchronization, it will be almost like real-time communication without any loss of information," Patla explained.
The research builds on a 2024 NIST framework for lunar timekeeping and tests relativity in new ways. Ashby emphasized its long-term value: "It may be decades before the surface of Mars is covered by the tracks of wandering rovers, but it is useful now to study the issues involved in establishing navigation systems on other planets and moons." Patla added that such work advances fundamental understanding: "It's good to know for the first time what is happening on Mars timewise. Nobody knew that before. It improves our knowledge of the theory itself."
As NASA eyes deeper Mars missions, this precise "Mars time zone" lays groundwork for interplanetary coordination, potentially realizing visions of solar system expansion.