A Day on Mars (A Sol) and How Time Actually Works There
Mars feels familiar — sunrises, sunsets, weather, seasons — but its clock ticks to a slightly different beat. A sol is 24h 39m 35s, and a Martian year is 687 Earth days. This guide explains sols, seasons, calendars, and the practical quirks of "living on Mars time."
Calculate your age: Age on Mars Calculator • Also see: Space Weight Calculator
Sols vs Earth Days
- 1 sol ≈ 24h 39m 35s (about 2.7% longer than an Earth day)
- Your schedule drifts ~+39 minutes per sol if you try to keep Earth clocks
Martian Year at a Glance
- 687 Earth days (~1.88 Earth years)
- Seasons exist (tilt ~25°), but each lasts nearly twice as long as on Earth
Handy Conversions
1 Earth day ≈ 0.973 sols1 sol ≈ 1.027 Earth days
Why a Sol Is Longer
A sol is measured noon-to-noon (solar day). Mars spins at a similar rate to Earth but slightly slower, yielding the extra 39 minutes.
For mission operations, that's non-trivial: teams working with rovers often "live on Mars time," shifting their day by ~39 minutes daily to align with local daylight at the landing site.
Seasons & Calendars
- Tilt similar to Earth → familiar seasons; elliptical orbit skews season lengths
- Proposed Martian calendars commonly divide the 668.6-sol year into practical months (e.g., 24× ~28-sol months), but standards aren't final — future colonies may choose differently
Practical Implications
Understanding Martian time is crucial for:
- Operations windows for communications and energy planning track true solar time
- Habitat design may implement lighting and routine cues to avoid circadian drift
- Agriculture plans revolve around longer seasons and thermal cycles
Converting Days and Sols
Example 1 — Earth to Mars
A mission lasts 100 sols. How many Earth days?
100 sols × 1.027 ≈ 102.7 Earth days
Example 2 — Mars to Earth
A crew spends 90 Earth days at a habitat. How many sols?
90 ÷ 1.027 ≈ 87.6 sols
Example 3 — Birthdays on Mars
Ada is 20 Earth years old. In Martian years:
20 ÷ 1.88 ≈ 10.6 → 10.6 Mars years
Use the Age on Mars Calculator for exact results based on your birthday.
Frequently Asked Questions
Why not just use Earth time on Mars?
You can for administration, but daily operations (power, EVA planning, communications) benefit from syncing to local solar time at the landing site.
Are "months" fixed on Mars?
Not officially. Several proposals exist; settlers will likely adopt one that balances scientific accuracy with everyday usability.
Will my body notice the longer day?
Most people can tolerate the ~39-minute shift short-term; long-term health still demands light cues, exercise, and sleep discipline.
Related Articles:
- Age on Mars Calculator - Calculate your exact age on the Red Planet
- Planetary Years Explained - Understand orbital periods across planets
- Weight on Mars - Discover how Mars gravity affects your weight
- Space Weight Calculator - Compare your weight across the solar system