From the abundance of craters on the Moon and Mercury, we know that numerous asteroids and meteoroids struck the inner planets during the very early history of the solar system. Is it reasonable to...

From the abundance of craters on the Moon and Mercury, we know that numerous asteroids and meteoroids struck the inner planets during the very early history of the solar system. Is it reasonable to suppose that numerous comets also pelted the planets 4.0 to 4.5 billion years ago? What effects would such a cometary bombardment have had, especially with regard to the evolution of the primordial atmospheres of the terrestrial planets and oceans on Earth?