Would you believe there are 40 planets are in our Solar System? If you ask the IAU the International Astronomical Union there are only 8, but that might not be the best possible answer. If we take a more physicsbased definition of what makes a planet a planet, we might have at least 40 planets in our Solar System, and maybe many more! Learn about these forgotten planetary bodies and what makes them so amazing with some help from New Horizons principal investigator Alan Stern. Let's explore!

Chapters:
0:00 Intro
0:20 What is a planet?
2:46 The planetary bodies
3:44 The big asteroids
4:42 The icy dwarfs
6:37 The 7 big moons
8:15 The other round moons
9:24 Conclusions

Media Credits:

Sagittarius A*: EHT Collaboration, CC BY 4.0
Kuiper Belt: by European Southern Observatory, CC BY 2.0
21 Lutetia: ESA / MPS / OSIRIS Team / Kevin Gill, CC BY 2.0
10 Hygiea: ESO/P. Vernazza et al./MISTRAL algorithm (ONERA/CNRS)
Rhea Silvia Sclupture: Sailko, CC BY 3.0
Makemake: Hubble ESA, CC BY 2.0
Haumea Ring: Kevin Gill, CC BY 2.0
Planet Nine: Kevin Gill/Elizabeth Gill, CC BY 2.0
Jupiter and moons: Jan Sandberg

End theme: "Jupiter" from Gustav Holst's "The Planets", performed by the United States Air Force Band (Public Domain)