Sedna: The dwarf planet that has no moon of its own
Planets, as all of you know, revolve around the sun in their respective orbits. But have you ever imagined why they never deflect from their fixed paths? Well, the answer is simpler than you expect. It is because their high gravitational forces keep them in line. In contrast, dwarf planets, because of their tiny size, lack the gravitational forces needed to pull themselves together in a specific orbit. So, they often deflect from their designated paths and roam around in an orbit-less motion. It is because of this absence of gravity that Pluto, our once ninth planet was demoted to the position of a dwarf planet in 2006. However, long before Pluto became a dwarf planet and the term became popular, several other dwarf planets have been existent, such as Eris, Ceres and Haumea and Sedna among others. Sedna was discovered in 2003 and is known for its eccentric orbit. Here’s what we know more about it.
Sedna: Still a mystery to astronauts
Sedna is far, far away from the Earth, even way past Pluto. Scientists estimate that it is approximately 11 to 13 billion kilometres away and most of its surface features are still a mystery. Probably, this is what has kept the scientist fraternity so intrigued about this dwarf planet. From what is known so far, Sedna is bright red in colour, almost as distinctive as that of Mars, and almost 100 times brighter than a full moon as seen from Earth. It is half the size of Pluto, approximately 1000 kilometres in diameter, or the same size as Pluto’s largest moon, Charon. As for its location, Sedna is situated at a frigid region in the solar system known as the Oort cloud, that is also home to other icy objects and various comets.
Scientists believe that Sedna takes the longest (around 11000 years) to revolve around the Sun, in comparison to all other known objects in the solar system. Its orbit cycle is so long, partially because of its distance and also for its eccentric and highly elliptical orbit. Sedna moves too slowly around the sun at a speed, which is 4 per cent of the earth’s. Here are some quick facts about Sedna for you:
- It has no moon, which makes it the only object orbiting the sun that has no satellite of its own.
- On a hot day, the temperature of this dwarf planet is presumed to be minus 237 degree Celsius.
Sedna was named after a Roman sea goddess
Sedna happens to be one of the rarest objects in the solar system that was co-discovered. On 14th November 2003, Michael E. Brown from Caltech University, Chad Trujillo from Gemini Observatory and David Rabinowitz from Yale University together discovered this dwarf planet. The team named Sedna after the Roman sea goddess, who resides at the bottom of the Arctic Ocean. Just like the sea goddess, the celestial object too lives far, far away in an icy cold region.