* Planet formation is a long and complex process: Planets don't form overnight. They take millions, even billions of years to coalesce from dust and gas. It's difficult to pinpoint an exact "birth date" for any planet.
* Our understanding of planet formation is evolving: Scientists are constantly learning more about how planets form, and it's possible that our current understanding of the ages of planets could change with new discoveries.
However, some scientists believe that the outer planets, like Neptune and Uranus, may be younger than the inner planets like Mercury, Venus, Earth, and Mars.
This is because the outer planets are made up primarily of lighter elements like hydrogen and helium, while the inner planets are mostly rock and metal. It's thought that the lighter elements took longer to coalesce into planets.
Ultimately, we can't definitively say which planet is the youngest. The process of planet formation is too complex and our knowledge of it is still incomplete.
