The Mysterious world of dwarf planets

An Introduction

In our solar system we can observe many types of celestial objects and other curiosities. Planets and stars were always the stars of the show, they have attracted human attention since ancient times and up until today, leaving behind many other interesting objects in the shadows. One of the most interesting and frequently overlooked class of celestial objects abundant in our solar system are dwarf planets. As the name suggests, dwarf planets are smaller objects which resemble planets but are however not true planets because of different properties. By definition: a dwarf planet is a planetary mass object that does not dominate its region of space (gravitationally) but is not a satellite, meaning it orbits a star directly.

Planetary Scientist Alan Stern History

The term “dwarf planet” was coined by the iconic planetary scientist Alan Stern back in 2000. However, objects recently labelled as dwarf planets have been discovered since 1801. Astronomers in the early 1800s have spotted the now labelled asteroid belt between mars and Jupiter and within it they discovered our system’s first dwarf planet, Ceres. Pluto, the most famous of all dwarf planets was discovered later on in 1930. Finally in the 1990s, astronomers were able to locate more dwarf planets beyond the orbit of Pluto and that started the controversy of the appropriate classification for these bodies.

The Five Dwarves

Our solar system may harbor many dwarf planets that we are not aware of yet, however through time we have been able to identify 5 major dwarf planets. All of them except Ceres lie in the Kuiper belt region of space in the far reaches of our solar system, a region that is thought to be full with remnants from planet formation. Estimates of undiscovered dwarf planets range up to tens of thousands but they are incredibly hard to spot in such a vast space, like needles in a haystack. The other four that are in the Kuiper belt are: Pluto, Eris, Makemake and Haumea. You’re probably wondering right now, hey wasn’t Pluto a planet? What happened? Well there’s an explanation behind that story.

The Plutonian Dilemma

Pluto was discovered back in 1930 by Clyde Tombaugh and it was labelled as the 9th planet shortly after. It was previously thought to be much larger than it actually is until its moon Sharon was discovered, which enabled scientists to accurately measure its size which turned out to be much smaller. Later on in 2006 Pluto lost its planetary status and was instead reclassified as a “dwarf planet”. This decision stirred much controversy among the scientific community and the general public as well. Since the discovery of Pluto and it was obvious it was different than the other 8 planets. It has a highly eccentric orbit that is way more irregular relative to planetary orbits. This orbit can place it closer to the sun more than Neptune at times. Also the orbital plane is tilted. Recently, a split within the scientific community happened and many are now reclassifying it as a Planet, but because of this reclassification it also means that the number of planets in the solar system increases from a mere 8 to nearly 100!

Expeditions

Dwarf planets are notoriously hard to observe and study because of their miniscule size. Even Ceres which is relatively close to Earth is still hard to observe. Thanks to the wonders of modern innovation and technology, two of the five major dwarf planets were explored by unmanned probes. Ceres, the dwarf planet lying within the asteroid belt was explored by NASA’s spacecraft Dawn. It orbited Ceres sending us clear direct photos for the first time as well as loads of scientific data in 2015. A few months later, a much more ambitious mission is set to arrive at its destination. The New Horizons mission was headed for the elusive Pluto and successfully arrives in the summer of 2015. It travelled approximately a whopping 5.25 billion kilometers, travelling for almost a decade to reach its destination. New Horizons is still online and is discovering the outer reaches of the solar system and perhaps beyond.

Future

While we already made a lot of fascinating discoveries in the world of dwarf planets, there is still much to see and much to do. We have yet to land a probe on the surface of any of the dwarf planets and even more ambitiously maybe a human being one day. Many of the dwarf planets in the outer reaches of the solar system may contain crucial information about the origins of the solar system and its formation. Scientists at NASA are hard at work designing new concepts and projects to discover these tiny worlds further as well as many space agencies around the world.