As humanity looks toward Mars for future exploration, scientists have made a key discovery: time actually passes faster
on the red planet than it does on Earth.
Physicists at the National Institute of Standards and Technology (NIST) have calculated that clocks on Mars tick, on
average, 477 microseconds faster per day than on Earth. This difference results from the planet’s weaker gravity and its
distinct orbital pattern, influencing how time is experienced and measured on Mars.
The research, published in The Astronomical Journal, also found that Mars’ eccentric orbit and the gravitational pull
from its neighbours can cause fluctuations of up to 226 microseconds a day throughout the Martian year. This variability
means that synchronising time between Mars and Earth is far more complex than it is for our Moon, where the offset is
Understanding these differences in timekeeping is essential as NASA prepares for future Mars missions. “The time is just
right for the Moon and Mars,” said NIST physicist Bijunath Patla. “This is the closest we have been to realising the
science fiction vision of expanding across the solar system.”
To determine the precise offset, researchers considered not only Mars’ gravity, which is about five times weaker than
Earth’s, but also the influence of the Sun, Earth, the Moon, and other planetary bodies. Mars’ distance from the Sun and
its eccentric orbit make the variations in time larger.
“A three-body problem is extremely complicated. Now we’re dealing with four: the Sun, Earth, the Moon and Mars,” Patla
If an atomic clock is brought to the Martian surface, it will tick at the same rate as on Earth, but when compared side
by side, the two clocks will slowly fall out of sync. Scientists liken this to a planetary time-zone difference, but far
more intricate due to relativistic effects.
These minuscule differences matter for technology. “If you get synchronisation, it will be almost like real-time
communication without any loss of information,” Patla noted, highlighting how even microsecond discrepancies can impact
future communications networks.
However, seamless Mars-Earth communication is still a long-term goal. “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,” said Neil Ashby.
“Like current global navigation systems like GPS, these systems will depend on accurate clocks, and the effects on clock
rates can be analysed with the help of Einstein’s general theory of relativity.”
Patla emphasised both the scientific and practical significance of this research. “It's good to know for the first time
what is happening on Mars time-wise. Nobody knew that before. It improves our knowledge of the theory itself, the theory
of how clocks tick and relativity,” he said. “The passage of time is fundamental to the theory of relativity: how you
realise it, how you calculate it, and what influences it.”