This drawing shows where trans-neptunian objects are found.
Click on image for full size

How many planets orbit the sun?

I was wondering if there is a new planet? Are there planets (a tenth planet?) after Pluto belonging to our solar system? What are the names of the new planets discovered in the solar system? Are there any objects that orbit the sun that are not in the same plane as the planets, excluding Pluto, comets, asteroids? Do we know any names to any other planets than those in our solar system? If yes, could you give me any examples?

Only 9 planets orbit the Sun. People have been finding other objects in the solar system, but none of them are planets. And none of them are the mysterious Planet X!

These objects are called trans-neptunian objects (TNOs). Trans-neptunian means that they are farther out than Neptune. The first TNO to be discovered (beside Pluto!) was discovered in 1992. Since then, over 300 of these objects have been found!

One of the most recent discoveries of a TNO was in October of 2000. Astronomers found a huge TNO and called it 2000 EB 173. What would you name a new TNO if you found it?

So, no new planets have been discovered in our solar system, but there have been many discoveries of planets outside our solar system. One example are the three planets found around the star Upsilon Andromedae.

Submitted by Jana (New Jersey, USA), Sean (Ohio, USA), John (Ohio, USA), Saravanan (India), Puneet (India), Cassie (Colorado, USA), Jason
(January 26, 2001)

Last modified January 26, 2001 by Jennifer Bergman.

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