In July 1992 the orbit of Shoemaker-Levy 9 passed within Jupiter's Roche limit, and Jupiter's tidal forces acted to pull the comet apart. SL9 was later observed as a series of fragments ranging up to 42 km in diameter. The majority of these fragments collided with Jupiter's southern hemisphere between July 16 and July 22, 1994, at a speed of approximately 60 kps. The prominent scars from the impacts were more easily visible than the Great Red Spot and persisted for many months. Three fragments however escaped Jupiter's gravity. They are designated SL9-A, SL9-B and SL9-C.
On the night of August 16th 1994 SL9-A (approximately 15Km wide) collides with the moon during a full moon roughly on the site of the landing site of Apollo 15. The impact is visible from the west side of Europe and the East coast of the Americas. Once the dust cleared a new crater is visible, scientists measure it at nearly 120 km across. the crater glows for several days as the lava at its base cools. Over the next three days large numbers of meteorites impact the Earth, these having been thrown up by the impact event on the moon, the largest piece estimated at 220 metres across impacts in central America 25 miles west of Mexico City. It forms a crater nearly a mile wide and kills over 15,000 people. Others impact the oceans and cause tsunamis ranging from 20cm to over 3 metres across the globe.
After passing the Earth SL9-B and SL9-C pass around the sun and make there way back into the inner solar system, while passing Venus their trajectories are altered, SL9-C (over 35Km wide) is captured by Venus and impacts on Christmas day 1994. Due to the impact the surface of Venus is visible for the first time as the heat and then the cold from the impact and dust clouds causes the surface temperature to drop by over 400 degrees Celsius.
SL9-B (12Km wide) is diverted toward Earth it passes within 100 km of the Earth on 27 February 1995. the slingshot effect causes the Comet fragment to circle the Earth over the poles. the orbit of the comet reduced by 50 Km every orbit and on the 18th of October 1995 SL9-B impacts Antarctica in the Queen Alexandra ranges near Mount Kirkpatrick (84°20′S 166°25′E) at an angle of 38 degrees.
SL9-B melts through the ice cap in less than one second and digs an elongate crater 97 km long, 65 km wide. The flash heat from the impact melts the surrounding surface ice to a width of 850Km and to a maximum depth of 3 km. The hot water created in the melt flows across the surface of the ice, melting more ice. The impact also causes several sub-ice volcanoes to erupt, these melt more ice. The water created measured approximately 4570 km cubed. The water washed across the continent and into the surrounding seas, some of the water made its way down to the base of the ice shelves, the water lubricated the glaciers of Antarctica causing them to flow more quickly into the southern ocean.
Due to the location of the impact and the fact that it impacted into 6Km of ice the Dust clouds from the impact do not effect the northern hemisphere, in the southern hemisphere the only noticeable difference is a two degree reduction in temperature for 6 months and an increase rainfall for five years due to all the vapourised water from the ice falling back to earth.
However there is a global effect, due to the massive ice melt on the Antarctic continent, the global oceanic levels rise by nearly 14 metres, inundating many of the major cities of the world, also due to the increased water in the atmosphere the number of storms across the globe is greatly increased leading to inland flooding in Australia, Southern Africa, and the USA. Parts of Australia flood inland causing large lakes to form, Lake Eyre fills to its highest point in recorded history with a maximum depth of nearly nine metres. Inland Australia and the deserts of Southern Africa and Chile green due to the increased rainfall.
With the initial global sea level rise several major cities are flooded including New York, London, Amsterdam, Milan, Pisa, Rome, Cairo, Lisbon, Stockholm, Sydney, Perth, Darwin, Los Angeles, San Francisco, Seattle, Vancouver, Mumbai, Shanghai, Beijing, Tokyo, Washington DC (Where the water laps at the bottom of the Capitol building's steps and the across the front lawn in front of the White house) and Istanbul. the global financial systems collapse due to the major financial centres being flooded. In many areas the electricity grids collapse causing riots and looting in the non flooded cities all over the world. In many countries the governments can no longer cope and they're countries collapse into anarchy.
By late 1997, Central America, most of Africa and parts of Southern Europe are in chaos, in a meeting of the United Nations at it's new base in Salt Lake City, the USA states that it will move to help the former countries of Central America return to civilization. The UK, France and Germany state that they will do the same in Greece, Turkey, Israel, Syria, Cyprus, Albania, Macedonia, Slovenia, Austria, Croatia, Bosnia, Serbia and Lebanon. Many people believe this to be an invasion that will incorporate these countries into the larger nations.
In 2002 the USA organises a referendum election in Mexico, Guatemala, and Belize, as part of the referendum bill is the countries voting to become commonwealths of the USA (like Puerto Rico). All countries pass the referendum by over 60% yes vote.
In the same year Cyprus, Greece, Macedonia, Bulgaria, Romania, Italy, Spain, Portugal, Georgia and Turkey vote to become part of the UK, Austria and Poland and the Netherlands become part of Germany and Albania to become part of France.
In 2004 the USA organises a referendum in Honduras, Nicaragua, El Salvidor and Panama. All apart from Panama vote to become commonwealths of the USA.
In August 2005 Syria, Lebanon, Croatia, Ireland, Norway, Denmark, Sweden, Iceland and Bosnia vote to join the UK, Slovenia, Switzerland Czech Republic, Slovakia, Belgium, Hungary, Luxembourg and Serbia vote to join France.
In June 2006 Mexico asks the USA to accept it as part of the union, after a four day meeting of the senate and congress, President George W. Bush signs a bill to accept Mexico into the union. The 31 states of Mexico are amalgamated into existing states and 20 new American states. Baja California and Baja California Sud are taken in to form Greater California, Sonora joins Arizona (giving this state a new coastline), Chihuahua joins New Mexico and Coahuilla, Neuvo Leon and Tamaulipas join Texas.
2007 Russian Federation reabsorbs the former Soviet republics of Estonia, Lithuania, Ukraine, Belarus, Latvia, Moldova, Armenia, and Azerbaijan, Finland also joins Russia.
In May 2008 Belize asks to join the USA as part of the union. The USA accepts and it is integrated as the new state of Belize. In July of 2008 Guatemala asks to join the union, it is also accepted as the new state of Guatemala.
At the end of 2008 the USA has 62 states.
December 2008, scientists visit the Antarctic crater for the first time they discover that the ice cap is starting to reform far quicker than was expected, ice at the base of the crater is measured using sonar as being 573 metres thick. They estimate that by 2150 the ice cap will be at its former levels and that sea levels will begin to drop by 2020. It is also announced that due to the large amount of vegetative growth that has occurred globally since the impact that global Carbon Dioxide levels have dropped back to 1960's levels.
In early 2009 Nicaragua, El Salvidor, Honduras, Costa Rica join to form the new country of United States of Meso-America (USMA) by late 2009 Panama has also join the USMA. In 2012 Columbia, Venezuela and many of the Caribbean Islands join the USMA.