Comets collisions

Two types of theory have been put forward to explain the formation and development of our solar system catastrophe and evolution. The former assumes a collision or coming together of two stars. As early as 1745, the French scientist Count Buf-fon postulated that the Earth had been torn out of the sun by a passing comet. He estimated the age of the Earth to be 70,000 years, while theology proclaimed that the Earth was less than 6,000 years old. 

An internal one by gas emission after accretion of the Earth, and An external one, via collisions with comets and asteroids which contained... 

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... 

The noble gas elements act as a record of the deposited material because they are essentially chemically inert and are also trapped within the ice of comets and meteorites. The late-heavy bombardment era must have affected both the Earth and the Moon similarly so an estimate of the collision frequency may be obtained by using the record of impacts on the Moon s surface. The collision rate calculated... 

Other events, evidence of which has not yet been detected in polar ice, may also eventually serve as useful time markers in the future. Large meteors or meteor swarms that ablated in the upper atmosphere may have left a significant chemical impact on succeeding snowfalls. The same may be true for cometary collisions or brushes with a comet s tail. As with ancient volcanic eruptions, such events need not have been historically documented. If identified and accurately dated in one ice core, these events will serve as useful time horizons in other cores. 

The Earth and other planetary bodies have been heavily modified by planetary-scale differentiation, smaller scale melting and the resulting chemical fractionations, collisions that mix material with different histories, and other processes. Samples of these materials are thus not suitable for determining the solar system composition. More primitive objects, such as comets and chondritic meteorites, have compositions more similar to the composition of... 

The elastic bounce cannot occure in actual astronomical phenomena. A nonelastic collision must occure. For instance, remember the comet Shoemaker-Levy collision with Jupiter in 1994. 

One factor that had previously cast doubt on an asteroid collision as the cause of the P-T catastrophe was the lack of iridium found in sediments from this period. However Becker and other scientists argue that this absence probably means the impacting object may have been a comet rather than an asteroid. It is also possible that such a blow could have intensified the volcanism already under way on earth at that time, delivering a one-two punch that almost obliterated life on earth, according to Becker. 

Since the SN was unlikely the major contributor to the earth s atmosphere, one may consider the following contributors (1) collision with comets, (2) volatilization of impacting material and (3) outgassing. One may distinguish two periods of outgassing. While the accretion energy due to impact was in principle sufficient to melt the entire Earth, this... 

These events liave sporadically happened even in our history. The Meteor Crater of Arizona is tliought to liave been formed between 20,000 and -30,000 years ago [58], Explosion of Tunguska meteor in 1908 and collision of Comet Shoemaker-Levy 9 against Jupiter in 1994 are the representative great events in the history. 

---