Last weekend, beachgoers at Dee Why Beach near Sydeny were met with a peculiar sight: thousands of bright green balls scattered all over the sand. The squishy spheres were about the size of golf balls and seemed to be made of some sort of algae or seaweed. Many joked that they were “alien eggs” or UFOs (“unidentified floating objects”), the Manly Daily reports.
Scientists, however, have another hunch. As the Viral Spell writes, certain types of algae sometimes roll around on the seafloor, forming into ball shapes. But, as one researcher noted, “that’s made of dead material and these look to be living.”
Still, there is an answer. Although extremely rare, 7News Sydney continues, there have been some past cases of multitudes of living balls of algae turning up on beaches, including in Japan, where they are referred to as marimo. The named was coined back in 1898 and is a combination of the words for “bouncy play ball” and “plant that grows in water.” In Iceland, on the other hand, the balls are referred to as kúluskítur or “ball muck.”
Most likely, plentiful sunshine combined with rough currents created the perfect conditions for forming the balls and depositing them on the beach in Sydney. While the seaweed that formed the balls normally secures itself to rocks, one scientist explained to 7News Sydney that “occasionally they get knocked off and rolled around in the ocean forming these beautiful little balls.”
For now, the balls are providing quirky entertainment for curious locals on Dee Why beach, but as scientists warn, after a few days spent under the spring sun they’ll be nothing but a smelly mess.