Dwarf planets are celestial bodies that orbit the sun and share some characteristics with both planets and asteroids. They are small in size, with diameters less than that of Earth’s moon. There are five officially recognised dwarf planets in our solar system: Pluto, Ceres, Eris, Haumea, and Makemake.
Pluto, once considered the ninth planet in our solar system, is the most famous of the dwarf planets. It has a highly elliptical orbit that takes it beyond Neptune, and it is known for its distinctive heart-shaped feature on its surface. Despite its small size, Pluto has five known moons and an atmosphere, making it a fascinating object of study for scientists.
Ceres, the largest object in the asteroid belt between Mars and Jupiter, is another intriguing dwarf planet. It was the first dwarf planet to be discovered and is the only one located within the inner solar system. Ceres has a rocky surface and a subsurface ocean of salty water, making it a potential target for future space missions.
Eris is the largest dwarf planet in our solar system and was discovered in 2005. It is located in the Kuiper Belt, a region beyond Neptune that is home to many icy objects. Eris has a highly elliptical orbit that takes it from 38 to 98 astronomical units from the sun, making it one of the most distant objects in our solar system.
Haumea and Makemake are also located in the Kuiper Belt and are both elongated in shape. Haumea has a rapid rotation and is surrounded by two moons, while Makemake is one of the brightest objects in the Kuiper Belt.
Studying dwarf planets can offer insights into the formation and evolution of our solar system, as well as potential clues about the formation of other planetary systems. They can also help us understand the properties of icy objects, which are thought to be common in the outer regions of the solar system and beyond.
Why was Pluto reclassified a dwarf planet
Pluto was reclassified as a dwarf planet in 2006 by the International Astronomical Union (IAU). The IAU created a new definition for a planet, which required that a celestial body must meet three criteria to be considered a planet:
- It must orbit the sun.
- It must have enough mass to form a spherical shape.
- It must have cleared its orbit of other debris.
Pluto meets the first two criteria but fails to meet the third. It shares its orbit with other objects in the Kuiper Belt, a region beyond Neptune that is home to many icy objects. This led the IAU to reclassify Pluto as a dwarf planet, along with other similar celestial bodies that do not meet the criteria to be considered a planet.
The decision was controversial and sparked debates among scientists and the public. Some argued that Pluto should be considered a planet based on its historical status and unique characteristics, while others supported the IAU’s decision to apply a clear and consistent definition of what constitutes a planet. Regardless, the reclassification of Pluto as a dwarf planet opened up new avenues for research and understanding of our solar system and its diverse objects.
Ceres
Ceres is the largest object in the asteroid belt between Mars and Jupiter and is classified as a dwarf planet. It was discovered in 1801 by an Italian astronomer, Giuseppe Piazzi, and was the first asteroid to be discovered. Ceres has a diameter of about 590 miles (940 kilometers) and a mass about 1/80th that of Earth.
Ceres is unique in our solar system because it is the only dwarf planet located within the inner solar system. It orbits the sun every 4.6 Earth years and is located about 257 million miles (414 million kilometres) from the sun. Its orbit is relatively circular and is not inclined, meaning it remains close to the plane of the ecliptic where most planets orbit.
Ceres is also the only object in the asteroid belt that is a dwarf planet. It has a rocky surface and a subsurface ocean of salty water, making it a potential target for future space missions. The presence of water on Ceres has raised the possibility that it could harbour microbial life or be a source of resources for future space exploration.
Ceres has been visited by NASA’s Dawn spacecraft, which orbited the dwarf planet from 2015 to 2018. The mission revealed many interesting features of Ceres, including bright spots on its surface that are believed to be deposits of salt. Scientists believe that Ceres may have a history of cryovolcanism, which is the eruption of icy materials instead of molten rock, and that it may have once had a global ocean that has since frozen.
Ceres is an important object of study for scientists, as it provides insight into the formation and evolution of our solar system. It also offers potential opportunities for space exploration and the search for life beyond Earth.
Pluto
Pluto is a dwarf planet located in the Kuiper Belt, a region beyond Neptune that is home to many icy objects. It was discovered in 1930 by American astronomer Clyde Tombaugh and was considered the ninth planet in our solar system until 2006 when it was reclassified as a dwarf planet.
Pluto has a diameter of about 1,471 miles (2,372 kilometres) and a mass about 0.002 times that of Earth. It has a highly elliptical orbit that takes it from 30 to 49 astronomical units from the sun, meaning it is often farther from the sun than Neptune. Pluto has five known moons: Charon, Nix, Hydra, Kerberos, and Styx. Charon is the largest moon and is about half the size of Pluto.
Pluto is known for its distinctive heart-shaped feature on its surface, which is believed to be the result of a large impact. It has a thin atmosphere made up of nitrogen, methane, and carbon monoxide, and its surface is covered in a layer of frozen nitrogen, methane, and carbon monoxide.
Pluto is an important object of study for scientists, as it offers insights into the formation and evolution of our solar system. Its location in the Kuiper Belt suggests that it may be composed of materials that are different from those found on the inner planets. Studying Pluto and its moons can help us understand the properties of icy objects, which are thought to be common in the outer regions of the solar system and beyond.
Pluto has been visited by only one spacecraft, NASA’s New Horizons, which flew by the dwarf planet in 2015. The mission revealed many interesting features of Pluto, including mountains made of water ice and a large plain known as Sputnik Planitia, which is thought to be a giant impact basin filled with frozen nitrogen.
Despite its reclassification as a dwarf planet, Pluto remains a fascinating object of study and a reminder of the diversity and complexity of our solar system.
Eris
Eris is a dwarf planet located in the Kuiper Belt, a region beyond Neptune that is home to many icy objects. It was discovered in 2005 by a team of American astronomers led by Michael Brown, and is the largest known object in the Kuiper Belt.
Eris has a diameter of about 1,445 miles (2,326 kilometres) and a mass about 0.0027 times that of Earth. It has a highly elliptical orbit that takes it from 38 to 98 astronomical units from the sun, meaning it is one of the most distant objects in our solar system. Eris has one known moon, Dysnomia, which is much smaller than Eris.
Eris is named after the Greek goddess of discord, a fitting name for an object that caused controversy and led to the reclassification of Pluto as a dwarf planet. The discovery of Eris and other similar objects in the Kuiper Belt led the International Astronomical Union (IAU) to create a new definition for a planet, which required that a celestial body must meet three criteria to be considered a planet. Pluto failed to meet the third criterion, which states that a planet must have cleared its orbit of other debris, and was reclassified as a dwarf planet, along with Eris and other similar objects.
Eris has a rocky surface and is covered in a layer of frozen methane, ethane, and nitrogen. It has a reddish colour, which is thought to be the result of methane and nitrogen reacting with sunlight. Eris also has a thin atmosphere made up of methane gas.
Studying Eris and other objects in the Kuiper Belt can offer insights into the formation and evolution of our solar system. They are believed to be remnants of the early solar system and can provide clues about the conditions and processes that led to the formation of planets and other celestial bodies.
Although Eris has not been visited by a spacecraft, it remains an important object of study for scientists, as it can help us understand the properties of icy objects, which are thought to be common in the outer regions of the solar system and beyond.
Haumea and Makemake
Haumea and Makemake are dwarf planets located in the Kuiper Belt, a region beyond Neptune that is home to many icy objects. They were discovered in 2004 and 2005, respectively, by a team of astronomers led by Michael Brown.
Haumea has a highly elongated shape and a rapid rotation, completing a full rotation every 4 hours. It has a diameter of about 1,200 miles (1,944 kilometres) and a mass about 0.0007 times that of Earth. Haumea is located about 43 astronomical units from the sun and has two small moons, Hi’iaka and Namaka.
Makemake is one of the brightest objects in the Kuiper Belt, with a surface that is covered in a layer of frozen methane, ethane, and nitrogen. It has a diameter of about 870 miles (1,400 kilometers) and a mass about 0.0007 times that of Earth. Makemake is located about 45 astronomical units from the sun.
Studying Haumea and Makemake can offer insights into the formation and evolution of our solar system. They are believed to be remnants of the early solar system and can provide clues about the conditions and processes that led to the formation of planets and other celestial bodies. Like other objects in the Kuiper Belt, they can also help us understand the properties of icy objects, which are thought to be common in the outer regions of the solar system and beyond.
Although Haumea and Makemake have not been visited by a spacecraft, they remain important objects of study for scientists, as they can help us better understand the diversity and complexity of our solar system. Their unique characteristics and properties make them fascinating celestial bodies that have much to offer in terms of understanding our place in the universe.
Are any of the dwarf planets visible from earth
Yes, some of the dwarf planets in our solar system are visible from Earth, but they may require telescopes or other astronomical instruments to see them.
Ceres, the largest object in the asteroid belt and a dwarf planet, can sometimes be seen with the naked eye, particularly during its opposition when it is closest to Earth. However, a telescope is usually needed to view it properly.
Pluto, Eris, Haumea, and Makemake, which are located in the Kuiper Belt, are much farther away from Earth and are therefore much more difficult to see. They can only be observed with large telescopes and sophisticated astronomical instruments. In fact, Pluto was not discovered until 1930, despite being the ninth planet in our solar system at the time, due to its distance and small size.
While it may be challenging to see the dwarf planets directly, they remain important objects of study for astronomers and space scientists. The information we gather from these objects helps us to better understand our solar system and the universe as a whole.