Solar System Research最新文献

The article is devoted to the significantly underestimated contribution of radiation from the young Sun to the formation of physical conditions on the early Earth. A new view on the faint young Sun paradox is presented: the main role in solving the paradox is given to the impact of the increased activity of the young Sun on the Earth’s atmosphere. The role of planetary organic films is considered as a climate-forming factor involved in resolving the faint young Sun paradox. The spectrum of radiation of the young Sun and the paradox of the discrepancy between the chlorophyll absorption spectrum and the spectrum of solar radiation are discussed, and also indicated a possible connection between the faint young Sun paradox and the origin and evolution of photosynthesis on Earth.

A review of the results on the migration of celestial bodies in the Solar System and in some exoplanetary systems is presented. Some problems of planet accumulation and migration of planetesimals, small bodies and dust in the forming and present Solar System are considered. It has been noted that the outer layers of the Earth and Venus could have accumulated similar planetesimals from different areas of the feeding zone of the terrestrial planets. In addition to the theory of coaccretion and the mega-impact and multi-impact models, the formation of the embryos of the Earth and the Moon from a common rarefied condensation with subsequent growth of the main mass of the embryo of the Moon near the Earth is also discussed. Along with the Nice model and the “grand tack” model, a model is considered in which the embryos of Uranus and Neptune increased the semimajor axes of their orbits from values of no more than 10 AU to present values only due to gravitational interactions with planetesimals (without the motions of Jupiter and Saturn entering into resonance). The influence of changes in the semimajor axis of Jupiter’s orbit on the formation of the asteroid belt is discussed, as well as the influence of planetesimals from the feeding zone of the giant planets on the formation of bodies beyond the orbit of Neptune. The migration of bodies to the terrestrial planets from different distances from the Sun is considered. It is noted that bodies from the feeding zone of the giant planets and from the outer asteroid belt could deliver to the Earth a quantity of water comparable to the mass of water in the Earth’s oceans. The migration of bodies ejected from the Earth is considered. It is noted that about 20% of the ejected bodies that left the Earth’s sphere of influence eventually fell back to the Earth. The probabilities of collisions of dust particles with the Earth are usually an order of magnitude greater than the probabilities of collisions of their parent bodies with the Earth. The migration of planetesimals is considered in exoplanetary systems Proxima Centauri and TRAPPIST-1. The amount of water delivered to the inner planet Proxima Centauri b, may have been more than the amount delivered to the Earth. The outer layers of neighboring planets in the TRAPPIST-1 system may contain similar material if there were many planetesimals near their orbits during the late stages of planetary accumulation.

This paper gives a review of the latest observational data on early stellar nucleosynthesis in the Universe compiled on the basis of an invited report at the “Astronomical Problems of the Origin and Development of Life. The Young Sun and the Earth” meeting-discussion dedicated to the memory of Academician M.Ya. Marov, March 19, 2024. The article presents modern observational results and theoretical ideas about the origin of chemical elements such as carbon, oxygen and nitrogen, which are important for the synthesis of organic matter.

The optical properties of the atmosphere limit the capabilities of ground-based astronomy. Taking telescopes beyond the atmosphere has allowed not only to significantly expand the spectral range of observations, but also to achieve great success in measurements in the visible range. In part, this has stimulated the creation of adaptive optical systems for ground-based telescopes. Of particular interest in the study of planets and exoplanets are observations in the IR and submm ranges. The capabilities of ground-based observations in these ranges are expanding, but will always remain limited. Extra-atmospheric astronomy has absolute priority in this. The article provides an overview of extra-atmospheric observatories in the UV, visible and IR ranges. Particular attention is paid to the new James Webb Space Telescope (JWST).

According to data obtained by the Ulysses spacecraft in 2017, high-latitude current sheets have been discovered in the polar heliosphere. They have been observed during solar activity minima in 1994 and 2007 at a distance of 2–3 AU above the south pole of the Sun. The discovered current sheets formed a conical surface rotating as a whole around the Sun’s rotation axis with the Carrington period. In this study, a semianalytical MHD model of conical current sheets is developed. The internal structure of heliospheric region bounded by these sheets—a magnetic funnel with reduced solar wind speed and the plasma beta—has been studied. Solutions corresponding to different intersections of the funnel by the Ulysses spacecraft have been obtained under different conditions near the Sun. The conditions under which the dimensions of the funnel agree with observations are clarified. For the first time, situations are treated in which the plasma and magnetic field parameters inside the funnel vary quasi-periodically in space. The study of the magnetic funnel structure challenges new issues for solar physics, whose solutions will enable a better understanding of the physical conditions on the early Earth and the features of the primary biosphere formation.

The Drake formula or equation represents the best known way of introducing the question of the distribution of life and intelligence in the Universe into the framework of quantitative science. A generalization of the Drake equation is presented in the form of a partial differential equation that includes the effects of the transfer of life elements from one exoplanetary system to another. Possible implications of this equation for assessing the prospects for detecting life beyond Earth are discussed.

The Russian space project with the automatic lunar station (ALS) Luna-28 is designed to deliver samples of lunar polar regolith to Earth. It is known that the regolith in the vicinity of the lunar poles may contain several percent by weight of water ice and other volatile compounds of cosmic origin. A significant portion of the lunar water could have been delivered to the Moon by comets. It is known that cometary water contains organic compounds, some of which have a complex prebiological structure. Similar comets collided with the Earth in the distant past and also delivered organic compounds of cosmic origin to our planet. According to the panspermia hypothesis, such compounds in the Earth’s primordial ocean could have initiated the process of the emergence of initial forms of primitive life. On the Moon, similar cometary organic matter may be preserved in pristine form in polar permafrost. Studying samples of the polar material delivered in the Luna-28 ALS return capsule in terrestrial laboratories will allow experimental verification of the presence or absence of extraterrestrial life spores in it.

The paper summarizes the main provisions of Alexander Spirin’s concept on the possible role of RNA, molecular machines, and molecular colonies in the emergence of life, including (1) the role of the capability of polyribonucleotides of spontaneous rearrangements and recombinations in the generation of RNA molecules and development of their structure, as well as in the early replication of RNA; (2) the principle of operation of molecular machines powered by the energy of Brownian motion and the need for their emergence to solve the problem of unwinding double-stranded molecules formed as a result of the complementary copying of RNA; (3) the role of molecular colonies formed during the replication of RNA in porous media as a mode of compartmentalization and as a prerequisite for the evolution in the precellular RNA world.

Computer modeling has shown that, during the collisional evolution of a solid-state component in gas–dust protoplanetary disks, porous dust clusters of widely ranging sizes are formed. Clusters of this kind have a well-developed internal structure that is topologically similar to the structure of porous catalysts, adsorbents, and carriers used in the organic synthesis technology. On the other hand, observational data currently obtained by such instruments as the Atacama Large Millimeter/submillimeter Array (ALMA) show that complex preorganic compounds rather than only water and volatiles are present in protoplanetary disks. This suggests the possibility that, in protoplanetary disks, there are mechanisms of capturing complex chemical compounds by porous dust clusters and transporting these compounds to warmer regions during migration. When getting to warmer regions of protoplanetary disks, dust clusters undergo a change in the pore space, which may increase the surface holding the captured compounds and, hence, intensify their reactivity.

Analysis of meteorites and terrestrial rocks using modern bacterial paleontology methods leads to the conclusion that Life did not originate on Earth, but originated in the form of a protogenome during the formation of the Solar System. Micron and submicron organisms have existed since the origin of the Solar System to the Phanerozoic and into the Phanerozoic on Earth. The study of this organic world can seriously change the understanding of the general development of the living world and the patterns of its evolution, as well as our understanding of the volume of minerals associated with the Precambrian.