Pluto, we have bad news for you…
Self Photoshopped image from NASA/ESA/HST
For 76 years, we have known of the tiny object at the ‘edge’ of the Solar System as the rebellious planet that refuses to follow convention. It does not orbit in the same plane as its other 8 siblings, with cheek in tongue it occasionally crosses its big brother’s path (Neptune), and for such a small planet is has an entourage of 3 moons. What’s more, Mike Brown of CalTech discovered that Pluto has bigger pals in its neighbourhood (like Sedna and Xena). What a problematic child.
In the end, the International Astronomical Union (IAU) drew a line and cast Pluto out of the exclusive Solar System Planet Club by voting on the definition of what constitutes a planet in our Solar System (as for exoplanets, it’s a resolution to debate another day). Now where does Pluto sit in the Sol family tree? Kicked from the Planet nuclear family, it’s now sitting in the ‘dwarf planet’ branch at the side. Even here, it’s still slightly small in comparison to its newly discovered brethren. As it now stands, officially the tally of planets is 8. Ceres, Sedna and Xena (or 2003UB313) are now in the group of ‘dwarf planets’ which could number in the hundreds.
Hopefully, the one with an identity crisis has a fixed identity now.
