Moon may be 'upgraded' to planet, scientist

At the 26th International Astronomical Union General Assembly (IAU) being held in Prague, scientists are trying to establish a formal, scientific definition for 'planet'. One US scientist said on August 22 that if the new definition of planet is approved, more celestial bodies will be classified as planets. In billions of years, earth's own moon may be classified as a planet.

Gregory Laughlin, a doctor of astronomy and astrophysics at the University of California, said that in the draft resolution presented to the International Astronomical Union, all spherical, celestial bodies are eligible to be classified as planets providing their volume and mass reaches the stipulated size. Planets and their satellites may also be reclassified. Where the center of gravity between a planet and its moon(s) is in outer space rather than the interior of planet, that satellite will one day be called a planet.

Dr. Kaughlin said that the moon is likely to become a planet in the theoretical sense. A collision between two celestial bodies some 4 billion years ago created the moon. It was quite close to the earth but the distance between the two has grown dramatically. The distance between the moon and the earth grows 3.75 centimeters a year.

"If the earth and the moon still exist in a few billion years, the barycenter of gravity between the two will move to outside the earth. When that happens, the moon may be regarded a planet," added Dr. Kaughlin.

According to the draft resolution put forward by the IAU Planet Definition Committee, there are 12 planets in total in our solar system. The new planets include Ceres, formally believed to be Charon, a satellite of Pluto and celestial body number 2003 UB313. Astronomers will vote on the draft resolution on August 24.

Founded in 1919, the IAU is the largest global organization of astronomers. The IAU General Assembly is held on a three yearly basis. This year the 12-day assembly is being held in Prague, the capital city of the Czech Republic.

By People's Daily Online

By People's Daily Online