How does Mercury end up with such extreme temperature swings between day and night?

Mercury’s thin exosphere is far too sparse to trap and redistribute heat the way Earth’s atmosphere does. Because the planet rotates slowly and has no thick insulating air, sunlight bakes the surface during the long daytime while heat escapes quickly after sunset. The result is one of the largest temperature ranges in the Solar System. NASA’s MESSENGER mission helped confirm that the planet’s surface and environment are shaped by this lack of atmosphere and by intense solar heating.