The theory that microorganisms or biochemical compounds from outer space are responsible for originating life on Earth and possibly in other parts of the universe where suitable atmospheric conditions exist.

• 有生源说，胚种论一种学说，认为来自宇宙空间的微生物或生物化学物是地球上生命的起源，并且在宇宙的其他部分可能有适合的大气状况存在