While some are debating whether Pluto is a planet or dwarf planet or a comet, a team of researchers was silently working to understand the history of the solar system. Their hard work paid off after discovering around 840 minor planets that are orbiting around the sun with their unique, well-defined orbits just beyond the icy planet, Neptune.
Our solar system is so tiny compared to the vast galaxy but filled uncountable mysteries. We made our neighbor, red planet, the only planet solely inhabited by robots. We measured gravitational waves to unlock the mysteries the universe. We discovered thousands of exoplanets that are in the habitable zone. Yet, we are entirely unaware of more than half of our solar systems. Now, scientists found 840 small worlds in the hard-to-explore region beyond Neptune. This discovery has increased our knowledge regarding the distant objects with well-defined orbits around the sun by 50%.
These little icy planets give hope for the possibility of the unseen planets roaming in the outer region of the solar system. The formation of our solar system was a long, slow, yet an amazing process. At the very beginning, in the sun’s childhood, it was surrounded by a massive disk, filled with tiny, growing planets–including the eight planets that we know–that gradually shifted outward and inward from the sun till they found their place in the solar system. However, the growing planets were randomly scattered, and became difficult to map. However, this discovery helps us reconstruct the missing data and answer of how far were these planets pushed.
The discovery is a fruit of five years of relentless research called Outer Solar System Origins Survey. The team used one of the world’s major telescopes, Canada-France-Hawaii Telescope on Maunakea in Hawaii to look for faint, slow-moving points of light within the dense star field of the Milky Way. The discovered 840 minor planets are scattered at distance between six and 83 astronomical units (au). One au is equivalent to the distance between the sun and the Earth. This enormous distance gives a clear idea of the orbits of these “trans-Neptunian objects”. These new planets are categorized into two major groups. One includes those planets that orbit around Neptune in roundish way, which extends from 37au to 50au from the sun. The second group contains those planets–including Pluto– that revolve around Neptune as they orbit around the sun.
The most astonishing discovery is that there are nine little worlds that take over 20,000 years to complete a rotation around the sun. This implies there must be several other unseen worlds that have similar orbits. Although how they create such bizarre path is still unclear. Some orbits are so far out that they barely get influenced by Neptune’s gravitational force. There are rumors that that the reason that these planets are clustered together by a giant planet, Planet Nine, which is still playing hide and seek with us. However, one thing is clear that this new finding will tell the old tale of the formation of solar system and it will play significant role in placing unknown pieces together to understand the history of the universe and our solar system.