Estimation of the flux density of galactic comets in the Orion–Cygnus branch based on number of shield volcanoes on Venus, craters on Mars and marine basins on the Moon

Based on data on shield volcanoes of Venus and the distribution of craters on Mars and sea basins on the Moon, the flux density of galactic comets in the Orion–Cygnus branch was calculated. The comets flux density is 5 × 10⁻¹⁰ year⁻¹ km⁻². This value was used to estimate the number, energy and fallings frequency of galactic comets on terrestrial planets in the period from ≈ 5 to 1 million years ago. The article shows, that the falls of such comets can explain the phenomena of "newest uplifts of Earth's crust" and "young volcanism" on Earth, the appearance of shield volcanoes on Venus, the asymmetric structure of Mars, as well as origin of large craters, seas and mascons on the Moon, Mars and Mercury. A hypothesis of formation on the Moon of the South Pole–Aitken basin by galactic comets is proposed.