Mayor and his colleague Didier Queloz were on Tuesday awarded the Nobel Prize for Physics for their research refining techniques to detect so-called exoplanets.
"If we are talking about exoplanets, things should be clear: we will not migrate there," Mayor told AFP near Madrid on the sidelines of a conference when asked about the possibility of humans moving to other planets.
"These planets are much, much too far away. Even in the very optimistic case of a livable planet that is not too far, say a few dozen light years, which is not a lot, it's in the neighbourhood, the time to go there is considerable," he added.
"We are talking about hundreds of millions of days using the means we have available today. We must take care of our planet, it is very beautiful and still absolutely liveable."
The 77-year-old said he felt the need to "kill all the statements that say 'OK, we will go to a liveable planet if one day life is not possible on earth'."