Time is a mysterious thing. We have come to think of it as something that flows constantly. Even when everything around us changes, a second remains a second and a minute remains a minute.
However, as (another) one of the consequences of Einstein’s theory of relativity, time is not the constant we once believed it to be. Einstein showed that the passage of time is linked to gravity, and because of this, time is now treated as a dimension alongside space itself.
Credit: ESA
This leads to some very interesting effects, such as time slowing down or speeding up in different parts of the Universe. One such effect is visible closer to home, in the form of time passing slightly faster on Mars.
Why Time Runs Differently On Mars
An added benefit of treating time as a dimension (not sure if it can be called a benefit) is that it can now interact with gravity. This leads to some fascinating effects, such as time dilation, where time slows to a crawl near black holes and other objects with extremely strong gravitational fields (cue Interstellar).
Similarly, motion also affects the passage of time. Objects moving at very high speeds experience time more slowly than those at rest, something that becomes noticeable as speeds approach that of light.
Photo by Aarav Iyer
While Mars doesn’t have any black holes of its own and doesn’t move anywhere close to the speed of light, there are still factors that affect how time passes there compared to Earth.
Since Mars orbits the Sun at a greater distance than Earth, its orbital speed is slower, which by itself would make time pass only slightly faster there. However, Mars's weaker surface gravity (check your weight on Mars here) and a higher eccentricity of its orbit make a much more noticeable difference in the passage of time on Mars compared to Earth.
How Much Faster Is It?
While this time difference is not enough that you'll be able to notice it while watching a nice sunset over Olympus Mons, it is still large enough that spacecraft engineers must account for it while writing the code for the software governing the spacecrafts' clocks.
To estimate its value, physicists at USA's National Institute of Standards and Technology (NIST) chose a reference point on Mars's surface (something like the sea level on Earth) and used it to estimate the gravity on the surface using data previously collected by NASA.
They also had to consider the effects of the gravitational pulls of Earth and it's Moon (Mars's moons Phobos and Deimos are far too small to have any significant effect) along with the Sun's gravitational force. This created a type of four body problem, which added in a bit of complexity to the process.
After taking everything into consideration, it was found that time moves around 477 microseconds (1 microsecond = 4 x 10-6 seconds) per Earth day faster on Mars than it does on Earth.
However, this value can increase or decrease by 226 microseconds per day over the course of a Martian year due to the egg shape of Mars's orbit and its relative position to other celestial neighbours (like Earth).
Why This Matters
At first glance, 477 microseconds might not sound a lot, but these tiny differences have to be accomodated for while setting up high speed communication systems like 5G, which requires timekeeping precision on the order of tens of microseconds.
On Mars, even time itself becomes something engineers and explorers will have to learn to work with!
But Hang On... What About The Moon?
Well, such a time difference also exists on the Moon, but it's a much smaller 56 microseconds (on average) per Earth day faster than on Earth. This is smaller than on Mars, but is still enough to disrupt any GPS like systems that might be created on the Moon.
This study was conducted by Neil Ashby and Bijunath R. Patla of the National
Institute of Standards and Technology (NIST). Their paper was published in the
Astronomical Journal and can be found here-
A Comparative Study of Time on Mars with Lunar and Terrestrial Clocks
Clear skies,
Aarav Iyer