Science of Star Wars: Can a Planet Have Two Suns?

There are many iconic scenes in the original Star Wars movie, A New Hope: the first lightsaber duel in the Star Wars universe between Obi-Wan Kenobi and Darth Vader; Obi-Wan presenting Luke Skywalker with his father’s lightsaber; and of course, Luke gazing at twin suns setting on his home planet of Tatooine as the Force theme plays in the background. 

The twin suns on Tatooine’s horizon are an enduring cinematic moment, one that questions the probability of a double sunset. Can a planet really have two suns? 

While many things about Star Wars are purely fictional, it turns out that planets orbiting two or more stars is not one of them. 

In 2011, NASA embarked on the Kepler mission, exploring the Milky Way galaxy to find other habitable planets. On this mission, they discovered Kepler-16b, a cold, inhospitable planet made up of about half rock and half gas and roughly the size of Saturn. 

Unlike Tatooine, Kepler-16b is not home to an amorphous crime lord named Jabba the Hutt who specializes in trafficking illegal goods, but it is a circumbinary planet—a planet that orbits two stars instead of one. 

This discovery was the first clear detection of a circumbinary planet and it led to further revelations of multiple planets orbiting two suns. 

Although Kepler-16b was not found to be habitable, scientists found planets Kepler 47-c, Kepler-1647b, Kepler-453b, and more, located within habitable zones—the areas around stars in which life could potentially exist. 

According to findings made by the Kepler team, up to half of all the stars in our galaxy are part of a binary star system. Planets being able to form around binary star systems shows how diverse the planetary systems in our galaxy are and increases the possibility of discovering other habitable planets. 

The NASA Kepler space telescope which found more than 2,600 planets outside our solar system was retired three years ago but their search for other habitable planets is not over. 

Last year, TESS, NASA’s Transiting Exoplanet Survey Satellite discovered TOI 700 d, an Earth-size planet, in a habitable zone. During its two-year long survey, over 60 other planets were found near habitable zones, including TOI 1338 b, a planet roughly 7 times the size of Earth. TESS’s extended mission is ongoing and gives hope for future scientific discoveries of planets that could possibly support life. 

As technology continues to advance, so does our knowledge of what’s possible. Tatooine is not the only Star Wars legend that has become a reality; like the Jedis and the Siths, engineers are developing lightsabers here on Earth that can change colour and cut through doors!

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