Here's why:
* Hubble's Orbit: Hubble orbits Earth, and Mercury is much closer to the Sun. When Hubble is pointed towards Mercury, the Sun's glare would overwhelm the telescope's instruments, making it impossible to take clear images.
* Sun's Gravity: The Sun's intense gravity would make it difficult for Hubble to maintain a stable orbit close enough to Mercury for effective observations.
While Hubble can't observe Mercury directly, other spacecraft, like the MESSENGER mission, have provided us with incredible images and data about the innermost planet.
