Next year, 2015, the New Horizons spacecraft will have a close encounter with Pluto. In the present study we discuss some possibilities regarding what the spacecraft may encounter during its approach to Pluto. Among them we should include: the presen
ce of geological activity due to heat generated by tides; the unlikely presence of an intrinsic magnetic field; the possibility of a plasmasphere and a plasmapause; the position of an ionopause; the existence of an ionospheric trans-terminator flow similar to that at Venus and Mars; and the presence of a Magnus force that produces a deflection of Pluto plasma wake. This deflection oscillates up and down in its orbit around the sun.
In 1980, Alvarez and colleagues proposed that, in the transition from the Cretaceous to Paleogene, a large impactor collided with Earth being the cause of the mass extinction occurred at the limit K / Pg. In 1980 there was no known impact structure,
which could be responsible for this extinction. It was not until 1991 that an international group of researchers proposed that a circular structure between 180 and 200 km, buried under Tertiary deposits in the Yucatan Peninsula in Mexico, was the crater formed by the impact proposed by the group of Alvarez (Hildebrand et al., 1991). It is very probable that an impact of this magnitude have had large effects on the surface and in the environment. To study these effects, it is necessary to estimate the characteristics that the impactor had. The literature often mentions the nature of the impactor, and has been proposed both an asteroid and a comet, and even a comet shower that produced periodic extinctions. However, the physical parameters of the impactor are not limited, so the aim of this study is to estimate the most relevant features of this one such as the size, mass and kinetic energy. We found that the kinetic energy of the impactor is in the range from 1.3e24 J to 5.8e25 J. The mass is in the range of 1.0e15 kg to 4.6e17 kg. Finally, the diameter of the object is in the range of 10.6 km to 80.9 km. Based on the mass of the impactor and iridium abundance in different types of meteorites, we calculate the concentration of iridium, which should be observed in the K/Pg layer. When compared with the measurements, we concluded that the best estimation is that the impactor was a comet.
Lithium is overabundant in cosmic rays because protons impact on carbon and oxygen nuclei and fission them. Among the products of this fission is lithium. Given this preference for carbon and oxygen atoms, in this work I propose that in an atmosphere
of almost pure CO2, such as Mars and Venus atmospheres, lithium nuclei are produced by interaction with cosmic rays. I calculated the production rate of lithium and came to the conclusion that, for pressures of two bars or greater, are produced between 21 and 81 lithium nuclei for each primary cosmic rays proton. For lower pressures, the production is less and almost nil with the current pressure of Mars or Earth (pressure of CO2). Assuming a rate of cosmic ray arrival at Mars equal to that of Earth, and a pressure greater than two bars throughout the history of Mars, the amount of lithium that would occur would be between 162 and 642 million metric tons (in the Earth lithium estimated reserves are 30 million metric tons). These values are an upper limit; the actual amount of lithium on Mars will depend on the time in which the planet had a dense atmosphere (> 2 bars). That is, the amount of lithium produced by cosmic rays, serves to estimate the time that Mars had a thick atmosphere and therefore the capacity for have liquid water on surface.
If we have a particle immersed in a field of random forces, each interaction of the particle with the field can enlarge or diminish its kinetic energy. In this work is shown that in general, for any field of random force with uniform distribution of
directions, the probability to gain kinetic energy is larger that the probability to lose it. Therefore, if the particle is submitted to a great number of interactions with the force stochastic field, the final result will be that the particle will gain energy. The probability to gain energy in each interaction is Pg=1/2 (1+T/(2Po)), where T is the impulse given by the field and Po is the momentum of the particle before the interaction. The probability to lose energy in each interaction is Pl=1/2 (1-T/(2Po)).
The study of the interior of the planets requires the knowledge of how certain parameters, as radius and mean density, vary according to the planet mass. The aim of this work is to use known data of the Solar System Planets and Transiting Exoplanets
(specifically the radius and mass) to create empirical laws for the planetary radius, mean density, and surface gravity as a function of mass. The method used is to calculate with the available data, the mean density and surface gravity for the planets and adjusts, using the least squares method, a function with respect to the radius-mass, density-mass and surface gravity-mass relations. In the mass interval from 10E19 to 10E29 kg, the planets separate in a natural way into three groups or classes which I called class A, class B and class C. In all these classes and with all the functions (radius, median density and surface gravity) those best fits are power laws.
In 1883, on the 12th and 13th of August, Mexican astronomer Jose A. y Bonilla observed several objects passing in front of the solar disk. In 1886 in the LAstronomie magazine, he reported his observations without providing a hypothesis explaining the
registered phenomena. Our objective in this work is to interpret, with current knowledge, what he observed in Zacatecas. Our working hypothesis is that what Bonilla observed in 1883 was a highly fragmented comet, in an approach almost flush to the Earths surface. The fragmentation of the comets nucleus is a phenomenon known since the XIX century. Using the results reported by Bonilla, we can estimate the distance at which the objects approach to the Earths surface, their size, their mass and total mass of the comet before fragmentation. According to our calculations, the distance at which the objects passed over the Earths surface, was between 538 km and 8,062 km, the width of the objects was between 46 m and 795 m and its length between 68 m and 1,022 m, the objects mass was between 5.58e8 kg and 2.5e12 kg. Finally, the mass of the original comet, before fragmentation, was between 1.83e12 and 8.19e15 kg, i.e., between 2e-3 and 8.19 times the mass of Halley Comet.
Genomic complexity can be used as a clock with which the moment in which life originated can be measured. Some authors who have studied this problem have come to the conclusion that it is not possible that terrestrial life originated here and that, i
n reality, life originated giga-years ago, before the solar system existed. If we accept this conclusion there is no other option than to admit that panspermia is something viable.The goal of this study is to propose a viable hypothesis for the transport of SLF from one planetary system to another. During the formation period of a planetary system giant planets can eject planets the size of the Earth, or larger, turning them into free-floating planets in interstellar space. These free-floating planets have also been called free floaters. If a free floater, which has developed life, enters a lifeless planetary system, it can seed the worlds of this system with SLF dragged by the stellar wind from one planet to another or by great impacts on the free planet. To support this hypothesis, I calculate the probability that one free floater reaches the planets zone of a planetary system, and also it was calculated the time it remains within the planetary zone in order to see if there is enough time to seed the host system.The probability of a free floater in the galaxy, within the region of the Sun, entering the planet zone of a system is 2.8x10-4, i.e., that {sim}3 of 10,000 free planets manage to enter some planetary system. At the galactocentric distance from the Sun I calculated that there are 21,495 free floaters floating around the galactic center. Hence, 6 free-floating planets manage to enter in planetary systems every galaxy rotation. Since the galaxy has rotated 54 times since its formation, then, {sim} 324 free floaters have entered some planetary system at the galactocentric distance of the Sun.
The planets magnetic field has been explained based on the dynamo theory, which presents as many difficulties in mathematical terms as well as in predictions. It proves to be extremely difficult to calculate the dipolar magnetic moment of the extraso
lar planets using the dynamo theory. The aim is to find an empirical relationship (justifying using first principles) between the planetary magnetic moment, the mass of the planet, its rotation period and the electrical conductivity of its most conductive layer. Then this is applied to Hot Jupiters. Using all the magnetic planetary bodies of the solar system and tracing a graph of the dipolar magnetic moment versus body mass parameter, the rotation period and electrical conductivity of the internal conductive layer is obtained. An empirical, functional relation was constructed, which was adjusted to a power law curve in order to fit the data. Once this empirical relation has been defined, it is theoretically justified and applied to the calculation of the dipolar magnetic moment of the extra solar planets known as Hot Jupiters. Almost all data calculated is interpolated, bestowing confidence in terms of their validity. The value for the dipolar magnetic moment, obtained for the exoplanet Osiris (HD209458b), helps understand the way in which the atmosphere of a planet with an intense magnetic field can be eroded by stellar wind. The relationship observed also helps understand why Venus and Mars do not present any magnetic field.
