Otherworldly Sunsets Revealed in Planet Simulation

By Christina Phillis

A beautiful sunset is a glorious sight. From the Earth’s surface, the pinks, blues, and yellows can swirl together like a celestial kaleidoscope. But not every sunset is the same — especially on different planets.

Geronimo Villanueva, a planetary scientist from NASA's Goddard Space Flight Center in Greenbelt, Maryland, created a sunset simulation to demonstrate what these colorful events might look like on other planets.

The sunset on Uranus, for example, is “a rich azure that fades into royal blue with hints of turquoise,” according to the Phys Org article “NASA simulation shows kaleidoscope of sunsets on other worlds” by Lonnie Shekhtman.

Sunset Simulations

The Villanueva animations show the sun setting from the perspective of someone on the surface of Earth, Venus, Mars, Uranus, and Titan looking up at the sky through a super wide camera lens. A white dot represents the sun.

During sunset, a specific location on the planet rotates away from the light of the sun, causing photons to scatter in different directions based on their energy and the atmosphere. Both Earth and Mars can sometimes have hazy sunsets with a halo of light at the end, which is caused by light scattered by dust or fog. Mars sunsets go from brown to blue because its dust particles scatter the color blue.

To test these reproductions, Villanueva used known sky colors of Uranus and other worlds. When sunlight reaches Uranus, red colors are absorbed by the mixture of hydrogen, helium, and methane in its atmosphere and blue and green light scatters to create its unique sunset.

Future Exploration

This and other aspects of a computer modeling tool may one day be used for a mission to Uranus. Using light measurements to determine chemical content will help scientists better understand the planet’s atmosphere.

Scientists can access these sky simulations with the Planetary Spectrum Generator, an online tool that recreates how light moves through the atmospheres of planets, exoplanets, moons, and comets and helps reveal their chemical makeups.

These detailed animations show that some space exploration can be just a click away with the right technology and a little imagination.