Trans-Neptunian object

Faraway Space Rocks

Trans-Neptunian objects, or TNOs, are special rocks and icy worlds that orbit the Sun much farther out than the planet Neptune. They live in cold, dark places beyond Neptune, in areas called the Kuiper belt and the scattered disc.

The very first TNO ever found was Pluto way back in 1930. For many years, Pluto was thought to be alone out there. But in 1992, scientists found another one named 15760 Albion. Since then, many more have been discovered!

These faraway objects are made of rock, ice, and sometimes even gases like methane. Some TNOs have tiny moons orbiting them. Scientists study them to learn about how our Solar System began.

Cool Facts About TNOs

• Pluto was the first TNO found and it even has its own system of five moons!
• TNOs can be different colors — some are gray, while others are red or even blue.
• The biggest TNO known is Eris, which is almost the same size as Pluto.

Famous TNOs You Might Hear About

Here are some of the most well-known TNOs:

• 134340 Pluto – The first and most famous TNO.
• 15760 Albion – The second TNO ever discovered.
• 90377 Sedna – A very distant TNO that stays far away from the Sun.
• 136199 Eris – One of the largest TNOs known.

Scientists are excited to keep finding and studying these mysterious worlds far from the Sun!