I would like to know if re-birth takes place on Earth always or on other planets too?
For example, if a person does bad karma on Earth, will he be re-born on Earth or it could be on any other planet?
It doesn't need to be earth planets. Depending on our activities we may go to different places. Gita 14.18 says:
Those situated in the mode of goodness gradually go upward to the higher planets; those in the mode of passion live on the earthly planets; and those in the abominable mode of ignorance go down to the hellish worlds.
However after suffering or enjoying the reactions of our deeds we will come back to earth planet. In Gita 8.16 it is said:
punar avartino ’rjuna
mam upetya tu kaunteya
punar janma na vidyate
From the highest planet in the material world down to the lowest, all are places of misery wherein repeated birth and death take place. But one who attains to My abode, O son of Kunti, never takes birth again.
punar avartinah they come back, is important. We come back to the earth after our quota of enjoyment or suffering expires. However those who practice self realization and will go back to spiritual world.
The Vedas are not clear on this point.
Swami Nikhilananda in his introduction to his translation of the Upanishads says:
The Brahmanda, or Egg of Brahma, described by the Hindu seers, may be likened, without pressing the comparison to far, to the solar system. The name is derived from it's shape which is oval, like an egg, or, more precisely, elliptical. There are innumerable Brahmandas, which constantly appear and disappear in the Ocean of the Great Cause (Mahakarana). The Brahmanda (Cosmic Egg) of the Puranas may be likened to a single solar system. Each Brahmanda has it's own Lord, Its Governor or Controller, who, needless to say, is a manifestation, in maya, of Brahman, or the Absolute.
So, if we stay with the same Brahma, then we would stay with this planet. If we don't stay with the same Brahma, then why not. I have also seen other interpretations that say that the Cosmic Egg is the universe, and Brahma is for this universe, not the solar system. In this other interpretation, there are an infinite number of universes.
I think a better translation of Gita 14.18 is:
Those who are established in sattva go upward; those who are moved by rajas remain in the middle; and those who are steeped in tamas, being weighted down by the tendencies of the lowest guna, go downward.
I think a any translation with
planets is a stretch. This verse can refer to birth on a different plane of existence as well as birth in a lower life form on this plane. It may or may not refer to another planet. I also do not like the translation with any
hellish connotation. Hell is a Western religious concept with connotations of fire and damnation. I think a better translation is sub-human regions.
A better translation of 8.16 is:
The dwellers in all the worlds, from the realm of Brahma downward.
Again, to use 'planet' is misleading, worlds refers to all planes of existence, not just this one plane.
One thing is true, be careful for what you wish for, because you will get it.