This is your Astronomy Tonight podcast.

On this day, September 29th, in the year 2009, we witnessed an extraordinary event that shook the astronomical community to its core. The MESSENGER spacecraft, on its third and final flyby of Mercury, made a groundbreaking discovery that changed our understanding of the innermost planet in our solar system.

As MESSENGER swooped past Mercury at a mere 142 miles above its cratered surface, its instruments detected something utterly unexpected: water ice in the permanently shadowed craters near Mercury's north pole. Yes, you heard that right, folks! Water ice on the planet closest to the Sun!

Now, you might be thinking, "Water ice on Mercury? That's about as likely as finding a penguin in the Sahara!" But here's where it gets even more fascinating. These craters are so deep that sunlight never reaches their floors, creating frigid pockets where temperatures can plummet to a bone-chilling -280°F (-173°C). That's colder than your ex's heart during a breakup!

This discovery was a game-changer, forcing scientists to reevaluate their theories about Mercury's formation and evolution. It opened up new possibilities for understanding how water is distributed throughout our solar system and raised intriguing questions about the potential for life in the most unexpected places.

So, the next time you're feeling a bit parched on a hot day, just remember: there's ice on Mercury! It might not make for a refreshing drink, but it certainly makes for some cool astronomical trivia.

And speaking of cool, if you enjoyed this cosmic tidbit, why not subscribe to the Astronomy Tonight podcast? We promise to keep bringing you the hottest news from the coldest corners of the universe. And if you're hungry for more mind-bending facts and astronomical wonders, check out Quiet Please dot AI. Thank you for listening to another Quiet Please Production. Keep looking up, space fans!

This content was created in partnership and with the help of Artificial Intelligence AI