NASA’s Curiosity rover has captured a rare glimpse into a full Martian day, from sunrise to sunset. The rover’s black-and-white navcams recorded a timelapse of the Red Planet’s skies, revealing key insights into Mars’ weather, atmosphere, and surface changes throughout the day.
Mars Day Length Close to Earth’s
The video shows that the length of a Martian day is very close to Earth’s 24-hour cycle. Mars takes 24 hours and 37 minutes to complete one rotation on its axis – with sunrise and sunset images showing the faint glow of light peeking over the horizon.
While Earth and Mars have similar tilt angles resulting in comparable day lengths, seasons on Mars can last nearly twice as long. The planet’s greater distance from the Sun means its year equates to 687 Earth days.
Twilight Glow Captured Before Sunrise and After Sunset
The images showcase a extended dawn and dusk period on Mars, as the sun sits just below the horizon. This twilight glow remains for some time before sunrise and after sunset.
In contrast, Earth’s atmosphere scatters more sunlight, meaning twilight is shorter. Mars’ thinner atmosphere allows direct sunlight to continue illuminating the surface after the sun dips below the horizon.
Table Comparing Twilight Duration on Earth and Mars
| Planet | Length of Twilight | Cause |
|---|---|---|
| Earth | Less than 1 hour | Thicker atmosphere scatters more sunlight |
| Mars | Up to 2 hours | Thinner atmosphere allows direct sunlight for longer when sun below horizon |
Clouds and Increased Wind Visible as Day Progresses
As the Martian day progresses from morning to afternoon, some high-altitude clouds can be seen developing in the late morning. The passage of time also reveals tall plumes of dust blowing in the wind.
Analysis of the shapes and motion of these dust plumes has helped scientists estimate wind speeds and directions at the planet’s surface. Guillaume Gronoff, a NASA atmospheric scientist, said the images showcase “just how dynamic the atmosphere can get”.
The extra tilt and longer length of Martian seasons means the planet’s atmosphere undergoes more significant changes than Earth. Over the course of a year, the air pressure varies drastically as frozen carbon dioxide at the poles substantially grows and shrinks.
What This Means for Future Exploration
The Curiosity images provide key insights to help NASA plan future crewed missions to Mars. Understanding the Red Planet’s day-night cycles, weather patterns and seasonal changes allows missions to better prepare.
Knowledge of daily temperature changes and daylight availability will inform decisions on solar power supply, equipment resilience requirements, and even crew wake-sleep cycles.
A Rare Treat From the Surface
The glimpse into a full Martian day offers a special perspective hard to replicate from orbit. Curiosity’s surface-level view shows the subtle lighting changes in a way not easily seen from spacecraft cameras higher above Mars.
The unique images celebrate Curiosity’s decade on Mars this year. In that time, the car-sized rover has fundamentally reshaped our understanding of whether life could have existed on Mars billions of years ago.
By reading the rocks and soil, Curiosity determined the Gale crater it is exploring was once a lake, with mild enough conditions to support ancient microbial life. That tantalizing evidence will guide NASA’s search for signs of extinct Martian life in future rover missions – the next launched in 2030.
For now, Curiosity continues its climb up the slopes of Mount Sharp – revealing Mars’ geological history layer-by-layer. And along the way, the rover’s hazcams will keep watch on alien sunrises and sunsets from the planet’s surface.
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