Theory of Relativity: Clocks on Mars are 477 microseconds faster per day
Clocks on the Red Planet run almost 500 microseconds faster per Earth day than they do here at home. This also has consequences for settlement plans.
Mars surface with tracks of the Perseverance rover
(Image: NASA/JPL-Caltech/ASU/MSSS)
On average, clocks on Mars run 477 microseconds faster per day than on Earth, although this can increase or decrease by up to 226 microseconds depending on the season. This was determined by the US measurement agency NIST, which, according to its own statement, has laid an important foundation for long-term human stays on the Red Planet. The work builds on the proposal for a coordinated lunar time presented a year ago. Both are important for navigation and communication on other celestial bodies, as these rely on extremely precise timekeeping, and according to Einstein's theory of relativity, clocks do not run at the same speed everywhere due to differing gravitational forces.
Preparation for an "Internet of the Solar System"
To determine the deviation between atomic clocks on Mars and those on Earth, the research group first identified a reference point on the Red Planet, explains the National Institute of Standards and Technology. The exact strength of gravity there could be calculated thanks to measurement data from various Mars probes. Furthermore, the influence of the Sun's gravity, as well as that of the neighboring giant planets Jupiter and Saturn, and of Earth and our Moon, had to be taken into account. Added to this is Mars's comparatively eccentric orbit, which causes the influences of celestial bodies to vary in strength throughout the year.
Even if the difference does not sound particularly large, knowing it is key to building an interplanetary communication network. NIST points out that, for example, 5G networks need to be accurate to a tenth of a microsecond. Only when the exact deviation is known can synchronized networks be built. Even though it will still take some time until then, the time was simply right to determine the deviation. This has now created a first building block on the way to a solar system-wide internet. At the same time, it became clear that the calculation is more difficult than assumed.
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If an atomic clock were set up on Mars, it would run the same for people on site as it does on Earth. Only a comparison with an atomic clock on Earth would reveal the difference. This follows from Albert Einstein's General and Special Theories of Relativity and is due to the weaker gravitational field on the Red Planet. Because the US space agency is currently planning a space station in lunar orbit and a permanent human presence on Earth's natural satellite itself, work on a coordinated lunar time has been underway for some time. The work of the NIST research group now builds on this. It is presented in a scientific article in The Astronomical Journal.
(mho)
