Please welcome 3 new members to our solar system. International Astronomical Union decided to bestow the status of ‘planet’ to three celestial bodies in our solar system:

  • Ceres, the largest asteroid in the astorid belt between Mars and Jupiter

  • Charon, which was considered as Pluto's moon, but it is upgraded due to its size. Now Pluto and Charon will be known as twin planets.
  • Xena (aka "2003 UB313"), another icy planet like Pluto, but larger than Pluto, found in the Kuiper belt.

Here is what defines a planet according to IAU:

  • The object must be in orbit around a star, but must not itself be a star
  • It must have enough mass for the body's own gravity to pull it into a nearly spherical shape

Wipe out the old list of planets from your memory and commit this new one…

Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon, and Xena.

This IAU decision couldn’t have been more timely. Just yesterday, we were talking about making a chart of planets for Ashwini. She wants her own telescope and we set a condition that she has to know the list of planets before she can get it.