The 2016 Olympics continue to prove entertaining in all forms this week, with the reveal of 32-year-old Ryan Lochte’s big, ugly lie and a sudden widespread knowledge of how useful race walking can be. Tonight’s pole vaulting competition remains among the most-anticipated Olympic sports due to its long-running origins in the competition. But there’s something a little different in the air surrounding the vault this year — or, rather, in the area’s gravitational pull.

It turns out that the centrifugal force of the Earth — which is the inertial force directed away from the axis of rotation that appears to act on all objects when viewed in a rotating reference frame — along with the very shape of our planet could actually affect pole vaulting results in Rio. The gravity force at the Olympics this year, compared to London back in 2012, is weaker, and will make a difference of nearly one centimeter.

As explained in the latest post from long-running webcomic xkcd, creator Randall Munroe notes that the same jump made this year in Rio will get an athlete 0.25% higher than in London. What’s more, this is just one of the major variable factors of this year’s pole vault competitions: status of equipment, the quality of which varies from athlete to athlete (because everyone has a preference) can be a huge game-changer as well. The gravitational changes can also affect the outcomes of other competitions in swimming and running.

Tonight’s women’s pole vault resulted in Greece’s Ekateríni Stefanídi scoring the gold, with the U.S.’s Sandi Morris taking home Silver, and New Zealand’s Eliza McCartney walking home with Bronze. Stefanídi and Morris tied with a score of 4.85 meters, but Morris ended up with Silver after a countback. While it’s not clear how much of an advantage Stefanídi had, she did not beat her personal record of 4.90 meters indoors.

Photos via xkcd, Getty Images / Alexander Hassenstein