Shoemaker-Levy comet

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... 

Comets are generally considered to be weakly consolidated, and active comets are commonly observed to split into fragments. This is sometimes due to the tidal forces of a close planetary encounter, such as affected comet Shoemaker-Levy when it passed close to Jupiter in 1992 and broke into 21 pieces. More commonly, a comet spontaneously fragments multiple times over its orbit period, without any obvious cause. Disintegrating comets leave trails of small particles in their wakes. These trails are known as meteor streams, and when the Earth passes through such a meteor stream, as it does several times a year, a meteor shower occurs. Meter-sized rocks are known to occur within cometary meteor streams. 

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. 

Forces make things happen. Forces speed things up and forces slow things down. There are attractive forces and repulsive forces. An attractive force pulls magnetic decals to the refrigerator door and pulled Comet Shoemaker-Levy into the churning surface of the planet Jupiter a repulsive force pushes two strips of scotch tape apart after they are stripped from a table top. In the arsenal of physical concepts, force is one of the most important. 

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. 

Kaiser, R.I. Ochsenfeld, C. Head-Gordon, M. Lee, Y.T. Suits, A.G. A combined experimental and theoretical study on the formation of interstellar C3H isomers. Science 1996, 274, 1508-1511. Kaiser, R.L Ochsenfeld, C. Head-Gordon, M. Lee, Y.T. Neutral-neutral reactions in the interstellar medium. IL Isotope effects in the formation of linear and cyclic C3H and C3D radicals in interstellar environments. Astrophys. J. 1999, 510, 784—788. Kaiser, R.L Ochsenfeld, C. Head-Gordon, M. Lee, Y.T. The formation of HCS and HCSH molecules and their role in the collision of comet Shoemaker-Levy 9 with Jupiter. Science 1998, 279, 1181-1184. Kaiser R.L Stranges D. Lee Y.T. Suits A.G. Neutral-neutral reactions in the interstellar medium. 1. Formation of carbon hydride radicals via reaction of carbon atoms with unsaturated hydrocarbons. Astrophys. J. 1997, 477, 982-989. 

The Roche Urn it was first described by Edouard Roche in 1848. It is the closest distance a body held together by self-gravity can come to a planet without being pulled apart by the planet s tidal (gravity) force. As a result, large moons cannot survive inside the Roche Limit. On July 7,1992, Comet Shoemaker-Levy 9 broke apart into 21 pieces due to tidal forces when it passed within Jupiter s Roche Limit on the subsequent pass, each of the comet s pieces collided with Jupiter. 

Moses, J. I. (1996). SL9 impact chemistry Long-term photochemical evolution. In The Collision of Comet Shoemaker-Levy 9 and Jupiter, 243-68, ed. K. S. Knoll, H. A. Weaver, P. D. Feldman. Cambridge Cambridge University Press. 

Squires, S. W, Vancleve, J., Matthews, K., Neugebauer, G., Shupe, D., Weinberger, A., Miles, J. W., Conrath, B. J. (1995). Palomar observations of the impact of comet Shoemaker-Levy-9.2. Spectra. Geophysical Research Letters, 22,... 

Due to the gravitational influences of planets, comets may even break up into several pieces. Comet Shoemaker-Levy 9 broke up into pieces and collided with Jupiter in 1994. This spectacular event was observable from Earth with even small amateur telescopes. 

During the impact of comet Shoemaker Levy on Jupiter (1994), a 22 GHz water MASER emission line was observed. This line can be used as a diagnostic for the existence of water on exoplanets. An observational program (called ITASEL = Italian Search for Extraterrestrial Life) started 1999 using the 32 m dish of the Medic-ina radiotelescope and from 32 candidates four emissions can be suspected. If such observations can be definitely confirmed it will prove the importance of cometary impacts for the deposit of water on exoplanets (Cosmovici et al., 2006 [80]). 

Maser detection in the interstellar medium was described by Elitzur, 1987 [118]. Water maser emission at 22 GHz may be a hint for cometary impacts that occur in extrasolar planetary systems. Such radiosignatures were proposed by Cos-movici et al., 2001 [79]. During the impact of comet Shoemaker-Levy 1994 on Jupiter observations made with the 32-m dish Medicina radiotelescope (Bolgna, Italy) revealed the delivery of water and for the first time also a water maser in the solar system. After the comet s nucleus exploded in the upper part of Jupiter s atmosphere, this maser was produced. 

BJoraker, G.L., Stolovy, S.R., Herter, T.L., Gull, G.E., Pirger, B.E. Detection of water after the collision of fragments G and K of Comet Shoemaker-Levy 9 with Jupiter. Icams 121, 411 21 (1996)... 

Mumma, DiSanti, Roettger (NASA GSFC), and Tokunaga have searched for 1.97 pm vibrational H2O emission in comet Shoemaker-Levy. This work will establish the ortho-to-para ratio and rotational temperature. 

When comet Shoemaker-Levy 9 crashed into Jupiter s surface, scientists viewed the event with spectrographs. What did they hope to discover ... 

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. 

Matthews, C. N. (1997). Hydrogen cyanide polymers from the impact of Comet P/Shoemaker/Levy 9 on Jupiter. Advance in Space Research, 19, 1087. 

The total radio intensity of Jupiter varies significantly over time (years), and appears to be correlated with solar wind parameters. The impact of comet D/Shoemaker-Levy 9 with Jupiter in July 1994 caused a sudden sharp increase in Jupiter s total flux density, by 20%. At the same time the brightness distribution of the radio flux density changed drastically. These observations suggest that the impact and associated phenomena significantly modified the electron distribution and possibly the magnetic field as well. 

Ground based detection of gaseous water in the coma of comet Halley was reported by Knacke et al., 1986 [185]. They observed at 1.4 and 1.9 pm and derived a mass loss rate from the intensities observed of 2 x 10 molecules/s. The detection of water group ions from comet Halley by means of Sakigake was described by Oyama and Abe, 1990 [257]. During the impact of Shoemaker Levy on Jupiter, water was detected in the resulting fireball of the fragments G and K (Bjoraker et al., 1994 [31] and 1996 [32]). 

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