Complex sentence: Their joint work on the infrared spectra of interstellar grains led to developing the hypothesis of panspermia, that proposes that life on Earth was'seeded' from space rather than arising through abiogenesis on Earth.
Split into simpler sentences: Their joint work on the infrared spectra of interstellar grains led to developing the hypothesis of panspermia. It proposes that life on Earth was'seeded' from space rather than arising through abiogenesis on earth.