European Stars And Stripes (Newspaper) - July 19, 1986, Darmstadt, Hesse                                Eation now attributed to giant crash Wal incl it just i the lion Mars la Gio Fitton the a i grail led the solar system. The giant Impact scenario seams to have Cut the gordian knot of the three classic theories said . Mokdh of the University of Arizona. It requires no magic no special pleading no extra twiddling. It just  the Moon May have gotten its Start in the Only truly Earth shattering moment in this planet s history. If it happened As the giant Impact theorists believe the catastrophe took place 4.5 billion years ago when a Rocky crust was starting to congeal around the still molten Earth. The Nate ant Lotar lit am was by then the residue of a dark milling Cloud of Gas with the Young Sun at its Center. In its outer regions 1he Bulky mass of Jupiter cast a perturbing influence on the system s gravitational dynamics. Closer to he Sun millions of tiny Oito iting Planell Simatos pulled themselves together into spinning balls that became the inner planets. Then according id the new theory a planetary projectile about one seventh of the Earth s size collided with the Earth probably with a sidelong glancing blow. The Energy of collision crushed and vaporized the surfaces of the two planets. Material squirted outward in a High pressure Jet at temperatures As High As 12,000 degrees fahrenheit. Over the next Lew Hundred or thousand years some of it came Back together far enough away from the Earth to remain in orbit. The Earth itself re formed As a combination of the old planet and the bulk of the projectile. A Lew astronomers still favor earlier theories but most have been persuaded. The giant Impact Model has realty become the sole remaining candidate said Alan p. Boss of the Carnegie institution of Washington. The consensus is much stronger than i be Ever  Strong support for this scenario has come in the last Tew months from simulations on the world s most powerful computers in projects run by separate groups of scientists at los Alamos and Sandia National laboratories. The models differ in design and in some physical details but the outcome is the same. You could t think of testing this Impact theory without huge computers said Willy Benz an astrophysicist at los Alamos. You need three dimensional code to do All  computer limitations have broken an impasse that made Moon study unappealing Lor a decade. People proposed All these theories but then they got stuck because there was no More they could  he said. So for a Long Lime the Moon was t fashionable any More. But it s a challenging question to know How this Guy was formed and it has a tremendous momentum right  when astronauts picked up the first Moon Rock in the summer of 1969, these three theories seemed possible the fission theory first proposed in 1860 by Charles Darwin s grandson George this theory holds that the original molten Earth was spinning so last that a chunk of it bulged outward and was Flung skyward some offered the fission idea As a Way of accounting for the vast hollow of the Pacific Ocean until that was explained More neatly by Continental Drift. The biggest problem with the fission theory was that it required a much bigger angular momentum or total rotation Energy than is seen now in the Earth Moon system and physicists know that angular momentum in a dosed system cannot be gained or lost. The double planet theory. The Moon formed independently in Earth orbit As she primordial Cloud gathered. The problem was that two bodies formed at the same place and time should be made of the same stud. Astronomers already knew the Earth and Moon to have disturbingly different compositions. The Earth has a dense Iron Core with 30 percent of its total mass while the Moon s Iron Core if it exists is much smaller. The capture theory. A body from elsewhere in the solar system came winging by and the Earth s Gravity captured it into orbit. The problem Here was dynamical As objects Fly around the Sotar system it is easy to gel collisions and near collisions but extremely difficult to gel a capture. Despite the objections each theory had thoughtful and convincing proponents and each made specific predictions about the chemical composition of the Moon. The Moon rocks were expected to decide the Issue. Instead they threw the Field wide open. I Borders the 9-foot High Barrier and fortified zone less boding less ugly less lethal Minghi says a though no less penetrable using the modernization of the Barrier in the 1970s, a armed with some 60,000 self starting scatter i that sprayed shrapnel when activated by trip wire. E weapons have been taken Down from the Sepo ints and the mine Fields have been removed i the no Man s land. In their place better electronic Ujj actors and higher fences have been installed. It e main Border Fence and the 100-mile Wall isolating t Berlin both built to halt a mass exodus to the i t Are the most often cd tend examples of effective of if no in. The soviet Union s Borders with Finland and. By Are also sealed with a series of heavily fortified parts of the world says geography professor Robert m of the University of Kansas there is a great Wrt Raton of activity along Borders. Some Are crowded refugees who Are often armed or better provided for the citizenry. In such places he says governments be in danger of losing control of their Borders. Me department geographer Ozemko Hopes that t end fences Are Only a Lemo Rary resurgence of a pry policy strategy that has been tried since Ancial me and roman times. Physical obstacles May Down the movement of people but they cannot  there Are proposals to Fence the entire -./, 33 Miles of the porous  Border. About Miles Are closed off with Chain link fencing most of Cal  Cut with regularity. They make More holes than an Patch says Mem Jarvis of the . Immigration naturalization service. Ii would be easier to guard than Patch  Walt dividing Berton toi its me tto Many. The stars and stripes Page 15