Interplanetary Soccer on Mars
The World Cup final in soccer will be held today. But lets be frank. What FIFA labels as `World’ refers merely to Earth. This represents a limited view of the Universe. There are hundreds of billions of other planets in the Milky Way galaxy alone. So many `worlds’ that one wonders whether we can play soccer on them? In the spirit of defining “habitable planets” as Earth-mass rocks with an atmosphere where one might find liquid water and the chemistry-of-life-as-we-know-it, we may define a new class of “soccerable planets”.
In 2014, a Sports Illustrated reporter contacted me with the news that FIFA president then, Sepp Blatter, hinted at the possibility of organizing an interplanetary contest, saying: “we shall wonder if one day our game is played on other planets and then one day we won’t have the World Cup, we will have interplanetary contests.” The reporter asked for my reaction as chair of the Harvard Astronomy department, and I wrote back: “There are a number of obstacles to organizing an interplanetary soccer cup with extraterrestrial (ET) players. First, we need to find planets where there is intelligent life. So far, we have not found evidence for even primitive forms of life on any other planet than the Earth. Second, we need to establish contact with ETs and make sure they are peace-seeking soccer fans and not militant imperialists. The nearest stars are a few light years away, implying that if we send the nearest ETs a question via radio communication, we should not hope to hear back the answer much earlier than a decade later. But lets stay optimistic and suppose that over several decades we are able to agree on the location and time for the soccer competition. We still need to meet the ET teams at that location. With existing propulsion technology, the trip to the nearest stars may take tens of thousands of years. This implies that we cannot simply send our best soccer players on a spaceship. We need to send both male and female ancestors of the players (who will be born thousands of years from now). Finally, we need to make sure that our players are well trained in the environment of the hosting planet; this implies getting used to its surface gravity, its temperature, illumination from the host star, and atmospheric composition. For example, if the atmosphere does not have as much oxygen as on Earth, the players will have to wear special space suits, affecting the quality of their play. Altogether, this entire operation sounds rather complicated for a simple soccer competition, so the FIFA president, Sepp Blatter, should not set our hopes too high that such an event will take place any time in the near future.” To validate my credentials, the reporter, Dan Treadway, posted a photo of me playing soccer and declared: “Case closed. Sorry, Sepp”.
But is the case really closed? A decade later, NASA and private entrepreneurs like Elon Musk, announced their long-term ambitions to settle on Mars. In fact, Elon expressed his desire to die on Mars. If so, surely he will enjoy local sports before death. This raises the question: “Is Mars soccerable?”
People who know me could testify that I am much more practical today than I was a decade ago. To that effect, I can now imagine the game being played inside a pressurized dome at a comfortable room temperature and atmospheric conditions. Also, I can imagine the game being played by a team of humans who came from Earth against those born on Mars.
But one cannot avoid worrying about surface gravity. The gravitational acceleration pulling the Martian soccer ball down would be 3.72 meters per second squared, 38% of Earth’s g. This means that a ball kicked up at the same speed on Earth and Mars will reach a distance that is (1/0.38)=2.63 times longer on Mars, neglecting its friction with the ambient air.
Gravity does not care about the mass of the soccer ball. At the end of the last Apollo 15 moonwalk, Commander David Scott dropped a 1,320 gram hammer and a 30 gram falcon feather at the same time. Because there was no air resistance the feather fell at the same rate as the hammer, just like Galileo Galilei had concluded in Italy four centuries earlier.
FIFA defines the optimal dimensions of a soccer field on Earth to be 100 by 70 meters. The increase of these dimensions by a factor of 2.63 would not be prohibitive for the engineering design of the host stadium on Mars. In fact, the stadium could be constructed inside a sufficiently large lava tube where the audience will be better protected from damaging cosmic rays by the rock overhead. The sizes of Martian lava tubes are naturally larger than those on Earth because of the lower surface gravity.
The duration of a day and the seasons on Mars resemble those of Earth, as both planets have a similar spin period and rotational tilt relative to the orbital plane of the planets around the Sun. Water ice from the Martian polar caps can be partially melted and served as refreshments to the players and Martian audience.
Obviously, the game will have to be transmitted live to Earth. The delay as a result of the finite speed of light would amount to 4 minutes at closest approach and up to 20 minutes otherwise. This means that spectators on Mars will cheer for a goal long before earthlings are aware of it. This will be the first instance where soccer fans will become aware of the restraining finiteness of the speed of light. After all, physics affects your quality of life, whether you like it or not.
ABOUT THE AUTHOR
Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He chairs the advisory board for the Breakthrough Starshot project, and is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. His new book, titled “Interstellar”, is scheduled for publication in August 2023.