Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more . CNN  —  Mars may have once hosted an ocean with waves that lapped against sandy beaches 3.6 billion years ago, according to new research. China’s Zhurong rover and its ground-penetrating radar detected the ancient shorelines when it operated from May 2021 to May 2022. The rover landed in Utopia Planitia, a plain within the largest known impact basin