NASA simulations provide tantalizing taste of sunsets on other planets
NASA has released a video showing what sunsets might look like on a number of different planets. The simulations were created by Geronimo Villanueva, a planetary scientist from NASA's Goddard Space Flight Center, using a computer modeling tool being developed for a possible future mission to Uranus.
If you watched a sunset on the Moon, it would be a bit anticlimactic. It would consist of the Sun simply winking out as it dropped below the horizon. There wouldn't be any twilight or dusk, and certainly not any of the spectacular colors associated with sunsets on Earth. This is because the Moon lacks one vital ingredient – an atmosphere. Our familiar sunsets are the result of sunlight passing through the atmosphere and changing angles, where it interacts with the gases, water vapor, and dust to produce the different shades and colors.
This interplay between light and different molecules is of interest to space scientists because it can reveal a lot about the composition and properties of a planet's atmosphere. In the case of Uranus, NASA says that a sunset there would be marked by a rich azure tone that fades into royal blue with hints of turquoise as the Uranian atmosphere's hydrogen, helium and methane absorb the longer-wavelength red portion of the light and scatter the shorter-wavelength blue and green sections of the spectrum as they collide with gas molecules and dust particles.
It's a process similar to what makes the terrestrial sky blue. It's also one that could be a valuable tool to study the atmosphere of Uranus when visited by some future spacecraft. For testing reasons, Villanueva simulated sunsets on Uranus and other worlds using an online tool called the Planetary Spectrum Generator, which was developed to give scientists an understanding of the atmosphere and surface composition of different planets, exoplanets, moons, and comets by replicating the way light travels through their atmospheres.
In the first video below, the Sun is shown moving as if seen from the surface by a wide-angle lens on Uranus, Earth, Mars, Titan, and Venus, while the second provides a different perspective.