C/2025 R2 is a long-period comet discovered in 2025 during routine sky surveys. Like all comets it is a primordial relic of the solar system’s formation 4.6 billion years ago — a frozen body of ice and dust from the outer solar system that brightens dramatically as it approaches the Sun and volatile ices sublimate into a glowing coma and tail. Its orbital period suggests it originates in the distant Oort Cloud and may not return for tens of thousands of years.