Back in my day we had twenty-three planets

Astraea

Ceres

Earth

Egeria

Eunomia

Flora

Hebe

Hygiea

Irene

Iris

Juno

Jupiter

Mars

Mercury

Metis

Neptune

Pallas

Parthenope

Saturn

Uranus

Venus

Vesta

Victoria

Eunomia was the last of these to be discovered before the definition of planet changed in 1851, for the 1854 edition of the Berliner Astronomisches Jahrbuch.

The definition of planets changed again, in 2006. Earth, Jupiter, Mars, Mercury, Neptune, Saturn, Uranus and Venus are the eight planets now.

If we had kept the post-1851, pre 2006 view of what’s a planet, we would now have thirteen planets. Ceres, Eris, Haumea, Makemake, and Pluto. Ceres was discovered almost a century before Pluto, but, has sometimes been classified as asteroid.

If we had kept the pre-1851 view of what’s a planet, we would now have over 523584 planets in our solar system. That would’ve been pretty awesome.