1715
Can you think of any now?
(piefed.cdn.blahaj.zone)
A place for majestic STEMLORD peacocking, as well as memes about the realities of working in a lab.

Rules
This is a science community. We use the Dawkins definition of meme.
Yes. Ceres was considered a planet when discovered in 1801 and around the 1950s began to be classified as an asteroid. It is now considered a dwarf planet like Pluto. It's the largest thing in the asteroid belt but is still sort of planet shaped.