Had the planetesimals that formed Titan brought methane, they would have brought these heavy noble gases as well.The absence of such gases indicates that methane most likely formed on Titan.

• 如果当初形成泰坦的微行星带来了甲烷，那麽应该会同时带来这些较重的惰性气体，所以，缺乏这样的气体，表示甲烷很可能是在泰坦上形成的。