Jupiter impact

After planetary accretion was complete there remained two groups of surviving planetesimals, the comets and asteroids. These populations still exist and play an important role in the Earth s history. Asteroids from the belt between Mars and Jupiter and comets from reservoirs beyond the outer planets are stochastically perturbed into Earth-crossing orbits and they have collided with Earth throughout its entire history. The impact rate for 1 km diameter bodies is approximately three per million years and impacts of 10 km size bodies occur on a... 

In 1994, a unique incident occurred the impact of the Shoemaker-Levy comet on the Jovian atmosphere. Die strong gravitational field of Jupiter caused the comet to break up before it could enter the atmosphere, and the parts of the comet crashed separately into the atmosphere one after the other. This unique spectacle was observed by many observatories and also by the Galileo spacecraft and the Hubble telescope. It led to the discovery of yet another phenomenon the most intensive aurora effects in the solar system, observed at Jupiter s poles. Astronomers assume that the energy for these comes from the planet s rotation, possibly with a contribution from the solar wind. This process differs from that of the origin of the aurora on Earth, where the phenomenon is caused by interactions between the solar wind and the Earth s magnetic field. 

One more important property of Jupiter must be mentioned the Earth owes its relatively quiet periods (in geological terms) to the huge gravitational force of the giant planet. Jupiter attracts most of the comets and asteroids orbiting in its vicinity, thus protecting the Earth from impact catastrophes ... 

A new reservoir of comets may have formed at around 5 AU in a local orbit around Jupiter or at least perturbed by its gravitational attraction. A comet close to Jupiter would simply have been captured, delivering its chemical payload to the ever-increasing gas giant. Some comets would merely have been deflected towards the inner terrestrial planets, delivering a similar payload of water and processed molecules. Cometary impacts such as the spectacular collision of the comet Shoemaker-Levy 9 with Jupiter would have been common in the early formation phase of the solar system but with a much greater collision rate. Calculations of the expected collision rate between the Earth and potential small comets deflected from the snow line may have been sufficient to provide the Earth with its entire... 

Fig. 1. A schematic diagram of the orbital positions of the moons of Jupiter discovered by Galileo. Their positions are scaled to Jupiter s radius (Rj) with properties given in Table 1. Note these satellites, like our moon, are all phase locked to the parent planet, hence the same side faces Jupiter throughout each moon s orbit. Since the magnetic field is attached to Jupiter, it rotates faster, therefore, in addition to ions and electrons moving up and down the field lines and impacting the satellites, there is a net preferential flow onto the hemisphere trailing the satellite s motion.

Surface compositions of icy satellites can be observed by reflection spectroscopy (UV to near-IR 0.2-5 pm) [5J. The physical properties and surlace compositions of icy bodies are summarized in Table 9.4. Major satelhtes of Jupiter (except for lo), Saturn, and Uranus show clear evidence of H2O ice (ice I) on Oieir surfaces. Altliough physical properties, such as density, radius, albedo, and surface structure of tlrese satellites differ greatly, they share basic compositional similarity. It is thus assumed that the ice of these satellites is pure H2O when we discuss Oieir internal structiue. The large spectral differences among satellites reflect surface modification histories by impact, volcanism, tectonics, and solar radiation. It is noted that SO2, O2, and O3 are trace components and contaminants. No NH3 or CH) ices, predicted by the equilibrium condensation theory, have yet been detected on these satellites. 

There are many icy bodies in addition to comets in the solar system they are icy satellites and Kuiper belt objects. Icy satellites of the Jupiter and Saturn systems were observed by spacecraft to clarify their densities and surface compositions. As a result, it is widely accepted that the main component of icy satellites is water ice, and the existence of water ice is confirmed by the observation of near infrared reflectance spectra. Icy satellites were revealed to have various surface morphologies and geologic activities depending on their origin and the thermal evolution process. Most of the icy satellites have densities from 1 to 2 g/cm which means that these bodies are a mixture of ices and silicates. Icy satellites were formed by collisional accretion of small porous bodies. These bodies could be ice-silicate mixture and the porosity was corrupted according to their growth. Therefore, impact properties of an ice-silicate mixture with various porosities are necessary to be clarified in order to study the formation process of icy satellites. I review systematic experimental results on impact of ice-silicate mixture in Section 3. 

The physical phenomenon utilized for the first time by Field [31a] and Munson [31b] is as old as the universe itself. In the MS source, a gas plasma is produced at a pressure of O.I-l Torr (in electron impact, this pressure is of the order of 10 -10" Torr). If the reagent gas is methane, CH5, CjH, etc., are produced after reaction. These ions have been detected in the gas plasmas surrounding Jupiter and Saturn [32] and those which compose certain stars. 

Astrologers regard those five planets, the ones you can see for yourself in the night sky (and sometimes during the day), as the ones with the most immediate impact on the individual. That s why Mercury, Venus, Mars, Jupiter, and Saturn are known as the personal planets. The outer planets, which aren t visible without a telescope, are less personality-driven and more generational in their effects (with exceptions that 1 note in Chapter 10). 

Acetylene has been observed in the atmospheres of Jupiter and Titan [33, 34] and more recently has been identified in significant abundance in comet Hyakutake [35]. Following the discovery of acetylene in Hyakutake, photochemical experiments have demonstrated [36] that this molecule is a likely precursor of C2, a widely observed component of comets. Acetylene itself may therefore be a ubiquitous constituent of comets. It has been proposed [37] that polymerization of acetylene in cometary impact on planetary atmospheres may be responsible for the formation of polycyclic aromatic hydrocarbons (PAHs) which may in turn be responsible for the colors of the atmospheres of Jupiter and Titan. Shock-induced polymerization of acetylene has been observed in the gas phase [38], and static high-pressure experiments have demonstrated polymerization of orthorhombic solid acetylene above 3 to... 

Any body in our solar system that has a surrounding neutral gas envelope, due either to gravitational attraction (e.g., planets) or some other processes such as sputtering (e.g., Europa) or sublimation (comets), also has an ionosphere. The very basic processes of ionization, chemical transformation, and diffusive as well as convective transport are analogous in all ionospheres the major differences are the result of the background neutral gas compositions, the nature or lack of a magnetic field, and the differences in some of the important processes (e.g., photo versus impact ionization). The remainder of this chapter describes the characteristics of the Venus ionosphere as a representative example of the so-called inner or terrestrial planets, the ionosphere of Jupiter as representative of the outer or major planets, and finally the ionosphere of Titan to represent one of the moons in our solar system. 

Given that Jupiter s upper atmosphere consists mainly of molecular hydrogen, the major primary ion, which is formed by either photoionization or particle impact, is H J. H+ ions are also created by either dissociative ionization of H2 or by direct ionization of atomic hydrogen. At high altitudes, H+ can only recombine directly via radiative recombination, which is a very slow process. It was suggested some time ago that H+ could charge exchange, with H2 excited to a vibrational state v > 4. The vibrational distribution of H2 is not known, but recent calculations indicate that the vibrational temperature is elevated at Jupiter, but it is not clear how important this effect is. 

The twelfth man to set foot on the Moon in December, 1972, was a scientist. The first eleven were military pilots, but Harrison H. Schmitt was a professional geologist who later learned to fly aircraft On October 6, 2008, astronomer Richard Kowalski discovered that a small asteroid was headed for an impact with Earth. Later calculations predicted that it would hit within the next thirteen hours somewhere in the Sudan. It did, and by December, more than forty-seven meteorite fragments had been collected. In the search for extraterrestrial life. Mars always seemed the most promising place to look. However, strong evidence of warm oceans of water beneath the icy surface of Jupiter s moon Europa make it the more likely location for life. 

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