What would the Sun look like as it plunged below the horizon on a long day (17 hours) on Uranus? Or what would an evening sunset on Mars look like when we finally got there? Thanks to some NASA computer models, these scenarios are now a little easier to imagine.
What a sunset does is the interaction of sunlight, which includes all the colors of the rainbow, along with gases and dust in the atmosphere. The less atmosphere, the less impressive the sunset is.
Planetary scientist Gerónimo Villanueva, from NASA’s Goddard Space Flight Center in Greenbelt, has created simulations of what sunsets would look like on Venus, Mars, Uranus, Saturn’s moon Titan, and Trappist-1e.
The shows are pretty spectacular, as you can see below, with scenes shown as if you were aiming a camera with a super wide lens at the sky.
On Venus, for example, a bright yellow fades into orange, brown, and then black as the Sun disappears. Since the planet rotates on its axis so slowly, you would have to wait about 116 times as long as you would on Earth, which is just over half a Venusian year.
Not that you’re necessarily setting yourself up to watch the sunset on Venus, with its thick, CO2-laden atmosphere, intense surface pressure, and average temperatures of 471 degrees Celsius (880 degrees Fahrenheit).
These simulations are not only fun to watch. They also have a serious scientific point: the preparations before a possible fact-finding mission to Uranus. There’s still a lot we don’t know about the gaseous planet, and any reading of its atmosphere would need to interpret the levels of light reaching the spacecraft’s sensors.
With the data from this onboard simulation, the probe would have a better idea of what it was looking for and could better assess the composition of the atmosphere as it absorbs sunlight, what wavelengths are scattered, and why.
Here is another look at the beautiful sunset models:
The new models are now part of the planetary spectrum generator, built by Villanueva and his colleagues, which is used to interpret the light that reaches our telescopes and decode it to try to understand what the atmosphere is like on other worlds.
Mars is the only other planet we have a realistic chance of living on, unless we spend all our time in an incredibly strong and robust floating spacecraft that can withstand extremes of pressure and temperature.
Villanueva’s simulation shows what the Martian sunset would look like to its inhabitants, with the atmosphere creating a mix of muddy brown colors and bright yellows when the Sun disappeared behind the horizon.
In fact, these simulations are only part of the story: As the Curiosity rover has already shown, days on Mars can end with a distinctly bluish tint, as dust scatters the red wavelengths of light out of sight. , letting the blue wavelengths hit our eyes If only we could go and see for ourselves.