How could they have demoted Pluto, my favorite dwarf planet?* It had a beautiful heart on it too! In this post we’ll tell you all about our favorite dwarf in the Kuiper belt, and why it lost its status.
Pluto was first found by Clyde W. Tombaugh at the Lowell Observatory in Flagstaff, Arizona. That heart you see on Pluto? Its informal name is the Tombaugh Regio. But beware, not everything is as it seems on the outside. The left side of that heart actually has carbon monoxide ice! The center left part of the heart is known as Sputnik Platinum, and is thought to be a very young part of the dwarf planet since it has no craters. Aside from the heart, Pluto’s surface is mostly methane and nitrogen ice, with an icy ridge terrain. In some areas, the ice also has dark streaks in it, made by the winds blowing across the surface.
In our post about possible life in our solar system, we discussed that one of the common pieces of evidence for life was organic molecules on the surface. NASA’s Hubble Space Telescope has found these on Pluto as well! However, some of the other common pieces of evidence are not there, likely ruling out Pluto as a candidate for life… on the surface. For all we know, it may have a subsurface ocean with temperatures warm enough to sustain little critters.
And finally, the topic you have been waiting for! On the pivotal day of August 24, 2006, the International Astronomical Union (IAU) made the fateful decision to demote Pluto from its status as a planet. Pluto was then reclassified as a dwarf planet. The IAU reasoned this decision because Pluto did not meet all three requirements for being classified as a planet. In order for a celestial object to be classified as a planet, it must orbit around the Sun, have a spherical shape, and have cleared all other celestial bodies around its orbit. While Pluto does orbit around the Sun and has a spherical shape, it did not succeed in clearing the area around its orbit. The area around Pluto’s orbit is filled with Plutinos (celestial objects in Pluto’s orbit) and other objects from the Kuiper Belt. Unfortunately, emotional attachment to the celestial body was not a factor in the decision, so the IAU removed its planetary status, and Pluto became a dwarf planet.
In conclusion, Pluto may have been demoted to a “lower” status, but it is still a very exciting space rock that we should research further! Maybe you can do a bit of digging yourself when you grow up!
*More dramatic opener/rant: How could they have demoted Pluto? My favorite planet! Your favorite planet! Everyone’s favorite planet! Is no longer a planet! How could they!?
Photo credits: NASA, Unsplash, https://unsplash.com/photos/-5V6VZxSQRo
Post By: Roshni P. M. and Hannah W.
Sources: