Sunrises Across the Solar System

Saturn’s upper atmosphere. Processed using calibrated narrow-angle near-infrared (CB3) and ultraviolet (UV3) and wide-angle red, green, and violet filtered images of Saturn taken by Cassini on November 17 2007. NASA/JPL-Caltech/SSI/CICLOPS/Kevin M. Gill.

Scientists have learned a lot about the atmospheres on various worlds in our Solar System simply from planetary sunrises or sunsets. Sunlight streaming through the haze of an atmosphere can be separated into its component colors to create spectra, just as prisms do with sunlight. From the spectra, astronomers can interpret the measurements of light to reveal the chemical makeup of an atmosphere.

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A Simulation of Sunsets on Other Worlds: From Venus to Titan

Credit: NASA/GSFC

When we think of exploring other planets and celestial bodies, we tend to focus on the big questions. How would astronauts live there when they’re not working? What kind of strategies and technology would be needed for people to be there long term? How might the gravity, environment, and radiation effect humans who choose to make places like the Moon, Mars, and other bodies place their home? We tend to overlook the simple stuff…

For example, what will it be like to look up at the sky? How will Earth, the stars, and any moon in orbit appear? And how will it look to watch the sun go down? These are things we take for granted here on Earth and don’t really ponder much. But thanks to NASA, we now have a tool that simulates what sunsets would look like from other bodies in the Solar System – from the hellish surface of Venus to the dense atmosphere of Uranus.

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An Enlightening Mosaic: Sunsets in 2011

Sunsets, June-December 2011 in Italy. Credit: Gruppo Astronomico Tradatese

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You’ve likely heard the phrase “axial tilt is the reason for the seasons” and here’s a great depiction of that axial axiom. A group of Italian amateur astronomers, the Gruppo Astronomico Tradatese (GAT), have been trying for a couple of years to take images of the Sun setting from the same location on the 21st of the month for several months in a row to show the link between the changing seasons and the movement of the Sun in our sky. The group specializes in outreach to schools and had a goal creating a mosaic of sunsets in 2009, the International Year of Astronomy. However, due to cloudy skies, they weren’t able to successfully obtain the sunset images until the second half of 2011.

“The availability of clear sky for seven dates around the 20-22 of each month starting from June was a crucial necessity,” Cesare Guaita, GAT President wrote to Universe Today. “Starting from 2009, we had to wait up to the second half of year 2011 for the right situation.”

These images of the Italian horizon at approximately 45°42’44” latitude and 8°55’52” longitude shows an Alpine mountain (Monte Rosa, 4634 m high) and trees changing in appearance with the changes of the season.

“As you can see, the sunset is located far away on the right of Rosa Mount at the summer solstice and far away on the left of the Rosa Mount at the winter solstice,” Guaita noted.

Each single picture is a mosaic of 2-3 frames, with the last picture (shown on top) taken on Dec 21, 2011 at 16:30 local time.

This would be a great project for any astronomy group or class. Congratulazioni to the members of the GAT, and we thank them for sharing their mosaic with Universe Today!