* Radiometric dating: Analyzing the decay of radioactive elements in meteorites, which are remnants from the early solar system, gives a very precise age for the solar system.
* Planetary evolution: Scientists have observed the formation of planets around other stars, and this helps them understand how our own planets likely formed.
So, while the exact date of formation is not known down to the day, we can confidently say that the planets in our solar system are incredibly old, dating back to the very early days of the universe.
