Dwarf Planet Ceres Turns Out To Be An Ocean World

Post author:Srishti Pandey
Post published:August 18, 2020

There are five dwarf planets in our Solar System. The most famous is Pluto. The other four, in order of size, are Eris, Makemake, Haumea, and Ceres.

Researchers have shed new light on the dwarf planet Ceres, which lies in the asteroid belt between Mars and Jupiter and is also the largest object in that belt.

Ceres now has the status of an “ocean world”, after scientists analysed data collected by NASA’s Dawn spacecraft. Their findings have been published as a series of papers in the journals Nature Astronomy, Nature Communications and Nature Geoscience.

A dwarf planet is a planetary-mass object that does not dominate its region of space and is not a satellite.

There are officially five dwarf planets in our Solar System. The most famous is Pluto, downgraded from the status of a planet in 2006.

The other four, in order of size, are Eris, Makemake, Haumea, and Ceres. The sixth claimant for a dwarf planet is Hygiea, which so far has been taken to be an asteroid.

Using observations made through the European Space Organisation’s SPHERE instrument at the Very Large Telescope (VLT), astronomers found that Hygiea may possibly be a dwarf planet since it satisfied the four criteria set by the International Astronomical Union (IAU) for a celestial body to be called a dwarf planet.

The dwarf planet was first spotted by Giuseppe Piazzi in 1801, who assumed that Ceres was the missing planet between Mars and Jupiter. It was classified as a dwarf planet in 2006 and is the first dwarf planet to be orbited by a spacecraft.

Mystery Solved 🧐

Bright areas on dwarf planet Ceres come from salty water underneath. Data from @NASA_Dawn answer two long-unresolved questions: Is there liquid inside Ceres, and how long ago was the dwarf planet geologically active? https://t.co/WWIA2xzAFj pic.twitter.com/FENnH4h7Q2
— NASA JPL (@NASAJPL) August 10, 2020

Dawn was launched in 2007 and visited Vesta and Ceres. In 2015, it went into the orbit around Ceres, and the information it collected reinforced the idea that dwarf planets could have hosted oceans over a significant part of their history.

Scientists are interested in this dwarf planet because it hosts the possibility of having water, something that many other planets do not have.

Another reason why scientists are interested in the dwarf planet Ceres is because studying it can give insights about the formation of the Solar System since it is considered to be a fossil from that time.

There are other dwarf planets and moons in our solar system where oceans exist, including the moons of Saturn and Jupiter.

OCEAN WORLD?

Ceres, NASA has said, “is a crucial piece of the ocean worlds puzzle”. “With a crust that mixes ice, salts, rock-forming minerals, and other materials, Ceres looks to be a remnant “ocean world,” wearing the chemistry of its old ocean and records of the interaction on its surface.” Scientists are interested in exploring ocean worlds because they may support life.

The observations from Dawn suggest the presence of briny liquid water under Ceres’s surface. Before the mission ended in October 2018, the spacecraft dipped to less than 35 km above the surface of the dwarf planet, due to which it was able to collect data in a higher resolution.

Now, by analyzing this data, which was collected at the end of the mission, scientists have determined that Ceres has a brine reservoir located about 40 km deep and which is hundreds of miles wide, making the dwarf planet, “water-rich”.

Significantly, in the papers, scientists note that an ocean world in Ceres was not expected, since it is too far away from the Sun and is too small to have radioactive materials to keep the oceans liquid for most of the dwarf planet’s history.

“Ceres can then be added to the rather short list of bodies for which we know the interior structure at high resolution, and the only ocean world to date (bar Earth),” the scientists note.

There are other dwarf planets and moons in our solar system where oceans exist, including the moons of Saturn and Jupiter.