The Ring Nebula (also known as the Messier 57 or NGC 6720) is located in the constellation Lyra. It is among the most well known and recognizable examples of a planetary nebula. This nebula was discovered by Antoine Darquier de Pellepoix in January, 1779. He reported that it was "as large as Jupiter & resembles a planet which is fading." Later the same month, Charles Messier independently made the same discovery while searching for a comet. It was entered into his list as the 57th object, giving it the designation M57. He speculated that the nebula was formed of multiple faint stars that he was unable to resolve with his telescope. The nebula is located at 0.7 kpc (2300 light-years) from Earth. The nebula has a visual magnitude of 8.8, and a photographic magnitude of 9.7. It is expanding at a rate of approximately 1 arcsecond per century (corresponding to 20–30 km/s), and this growth has been observed directly from photographs taken at intervals of 50 years. Its mass is approximately 1.2 solar mass. M57 is illuminated by a central white dwarf of 15.75 visual magnitude.
The interior parts of this nebula have a green tinge that is caused by the emission lines at 495.7 and 500.7 nm from doubly-ionized oxygen. These so-called "forbidden lines" are observed only in conditions of very low density, with a few atoms per cubic centimeter. In the outer region of the ring, part of the reddish hue is caused by hydrogen emission at 656.3 nm, which forms part of the Balmer series of lines. Ionized nitrogen also contribues to the red with forbidden lines at 654.8 and 658.3 nm.
M 57 is estimated to have been expanding for approximately 1,610 ± 240 years. It is bipolar, that is, it has thick equatorial rings with extended structure along its axis of symmetry. It appears to be a prolate spheroid with strong concentrations of material in its equator. Such a structure is a natural product of a bipolar model. From earth, it is viewed at about 30° from the symmetry axis.
M 57 exhibits knots characterized by a developed sense of symmetry. However, they are only visible as a silhouette against the background emission from the nebula's equatorial ring. M 57 may include N II emission located at the tips of the knots facing the central star. However, most of the knots are neutral and appear only in extinction. The existence of some knots with possible N II emission shows that they are located closer to the ionization front than those found in IC 4406. Some of the knots exhibit well developed tails which are often of a detectable optical thickness in the visual spectrum.
The interior parts of this nebula have a green tinge that is caused by the emission lines at 495.7 and 500.7 nm from doubly-ionized oxygen. These so-called "forbidden lines" are observed only in conditions of very low density, with a few atoms per cubic centimeter. In the outer region of the ring, part of the reddish hue is caused by hydrogen emission at 656.3 nm, which forms part of the Balmer series of lines. Ionized nitrogen also contribues to the red with forbidden lines at 654.8 and 658.3 nm.
M 57 is estimated to have been expanding for approximately 1,610 ± 240 years. It is bipolar, that is, it has thick equatorial rings with extended structure along its axis of symmetry. It appears to be a prolate spheroid with strong concentrations of material in its equator. Such a structure is a natural product of a bipolar model. From earth, it is viewed at about 30° from the symmetry axis.
M 57 exhibits knots characterized by a developed sense of symmetry. However, they are only visible as a silhouette against the background emission from the nebula's equatorial ring. M 57 may include N II emission located at the tips of the knots facing the central star. However, most of the knots are neutral and appear only in extinction. The existence of some knots with possible N II emission shows that they are located closer to the ionization front than those found in IC 4406. Some of the knots exhibit well developed tails which are often of a detectable optical thickness in the visual spectrum.
Today's Jumble (7/1/08) (Didn't like the answer much on this one.):
VELGA = GAVEL; PLUIT = TULIP; SICCUR = CIRCUS; IMPAGE = MAGPIE
CIRCLED LETTERS = ATIRSPE
"Pirates" can give you this.
"SEA TRIP"
Today is Build a Scarecrow Day, Creative Ice Cream Flavor Day, Financial Freedom Day, and International Joke Day. This week is National Unassisted Homebirth Week and Freedom From Fear Of Speaking Week.
Happy July 1st!!!!
Other things on this day in history:
251 - The battle of Abrittus is won by Goths against Romans. Roman Emperors Decius and Herennius Etruscus are killed.
1097 - Battle of Dorylaeum: Crusaders under Bohemond of Taranto defeat a Seljuk army under Qilich Arslan I.
1520 - La Noche Triste: Joint Mexican Indian force led by Aztecs under Cuitláhuac defeat Spanish Conquistadors under Hernán Cortés.
1569 - Union of Lublin: The Kingdom of Poland (Polish Crown) and Great Duchy of Lithuania confirm a real union, the united country is called the Polish-Lithuanian Commonwealth or the Republic of Both Nations.
1690 - Glorious Revolution: Battle of the Boyne as reckoned under Julian calendar.
1782 - American privateers attack Lunenburg, Nova Scotia.
1858 - The joint reading of Charles Darwin and Alfred Russel Wallace's papers on evolution to the Linnean Society.
1862 - Russian State Library is founded.
1862 - American Civil War: The Battle of Malvern Hill takes place, the final battle in the Seven Days Campaign, part of the George B. McClellan's Peninsula Campaign.
1863 - American Civil War: the Battle of Gettysburg begins.
1867 - The British North America Act, 1867 takes effect as the Constitution of Canada, creating the Canadian Confederation; John A. Macdonald sworn as first Prime Minister.
1870 - The United States Department of Justice formally comes into existence.
1873 - Prince Edward Island joins the Canadian Confederation.
1878 - Canada joins the Universal Postal Union.
1879 - Charles Taze Russell publishes the first edition of the religious magazine The Watchtower.
1881 - World's first international telephone call takes place between St. Stephen, New Brunswick, Canada, and Calais, Maine, United States.
1881 - General Order 70, the culmination of the Cardwell-Childers reforms of the British Army's organisation, came into effect.
1885 - United States terminates reciprocity and fishery agreement with Canada.
1890 - Canada and Bermuda linked by telegraph cable.
1892 - The Homestead Strike, a strike by the Amalgamated Association of Iron and Steel Workers against the Carnegie Steel Company, begins.
1898 - Spanish-American War: The Battle of San Juan Hill was fought in Santiago de Cuba.
1916 - World War I: First day on the Somme - On the first day of the Battle of the Somme 20,000 soldiers of the British Army are killed and 40,000 wounded.
1921 - Communist Party of China was founded.
1931 - United Airlines began service (as Boeing Air Transport)
1933 - Canadian Parliament suspends all Chinese immigration.
1935 - Regina, Saskatchewan police and Royal Canadian Mounted Police ambush strikers participating in On-to-Ottawa-Trek.
1942 - World War II: First Battle of El Alamein.
1942 - Australian Federal Govt becomes sole collector of Income Tax (State Income Tax Abolished).
1943 - Tokyo City merged with Tokyo Prefecture and was dissolved. Since then, no city in Japan has had the name "Tokyo." (Present-day Tokyo is not a city.)
1947 - British parliament passed India independence act. According to this took a decision for giving independence to India on August 15.
1948 - Quaid-i-Azam inaugrates Pakistan's central bank, the State Bank of Pakistan.
1957 - The International Geophysical Year begins (until December 31, 1958).
1958 - The Canadian Broadcasting Corporation links television broadcasting across Canada via microwave.
1958 - Flooding of the St. Lawrence Seaway begins.
1959 - The Party of the African Federation (PFA) holds its constitutive conference.
1960 - Independence of Somalia.
1960 - Ghana becomes a Republic and Kwame Nkrumah becomes its first President as Queen Elizabeth II of the United Kingdom ceases to be the Head of state.
1962 - Independence of Rwanda.
1962 - Independence of Burundi.
1963 - ZIP Codes are introduced for United States mail.
1963 - The British Government admits that former diplomat Kim Philby had worked as a Soviet agent.
1966 - First colour television transmission in Canada, from Toronto.
1967 - The European Community is formally created out of a merger with the Common Market, the European Coal and Steel Community, and the European Atomic Energy Commission.
1967 - Canada celebrates the 100th anniversary of the British North America Act, 1867.
1968 - The CIA's Phoenix Program is officially established.
1968 - The Nuclear non-proliferation treaty is signed in Washington, London and Moscow by sixty-two countries.
1968 - Formal separation of the United Auto Workers from the AFL-CIO.
1970 - President General Yahya Khan abolished One-Unit of West Pakistan restoring the provinces.
1972 - Andreas Baader, Jan-Carl Raspe and Holger Meins of the Red Army Faction are captured in Frankfurt after a shootout with the police.
1972 - First Gay Pride march in England
1976 - Portugal granted autonomy to Madeira.
1978 - Northern Territory (Aus) granted Self-Government.
1979 - Sony introduces the Walkman.
1980 - O Canada officially becomes the national anthem of Canada.
1983 - A North Korean Ilyushin Il-62M jet en route to Conakry Airport in Guinea crashes into the Fouta Djall Mountains in Guinea-Bissau, killing all 23 people on board.
1984 - The PG-13 rating is introduced by the MPAA.
1987 - American radio station WFAN in New York City is launched as the world's first all-sports radio station
1988 - Bologna, Italy: Quartetto Cetra's last concert after over forty years' musical career.
1990 - German re-unification: East Germany accepts the Deutsche Mark as its currency, thus uniting the economies of East and West Germany.
1991 - The Warsaw Pact is officially dissolved at a meeting in Prague.
1997 - The People's Republic of China resumes sovereignty over the city-state of Hong Kong, ending 156 years of British colonial rule.
1999 - The Scottish Parliament is officially opened by Queen Elizabeth on the day powers are officially transferred from the old Scottish Office in London to the new devolved Scottish Executive in Edinburgh.
2000 - Vermont's civil unions law goes into effect.
2000 - The Oresund Bridge, connecting Sweden and Denmark, opens for traffic.
2002 - The International Criminal Court is established to prosecute individuals for genocide, crimes against humanity, war crimes, and the crime of aggression.
2002 - A Bashkirian Airlines (flight 2937) Tupolev TU-154 and a DHL (German cargo) Boeing 757 collide in mid-air over Ueberlingen, southern Germany, killing 71.
2004 - Saturn Orbit insertion of Cassini-Huygens begins at 01:12 UT and ends at 02:48 UT.
2006 - The first operation of Qinghai-Tibet Railway in the People's Republic of China.
2007 - Smoking in England is banned in all public indoor spaces. With the ban already in force in Wales, Scotland and Northern Ireland, this means it is illegal to smoke in indoor public places anywhere in the UK. Ban also put into effect in Australia.
2007 - Prince William and Prince Harry throw a concert in memory of their mother the late Diana, Princess of Wales, on what would have been her 46th birthday.
1097 - Battle of Dorylaeum: Crusaders under Bohemond of Taranto defeat a Seljuk army under Qilich Arslan I.
1520 - La Noche Triste: Joint Mexican Indian force led by Aztecs under Cuitláhuac defeat Spanish Conquistadors under Hernán Cortés.
1569 - Union of Lublin: The Kingdom of Poland (Polish Crown) and Great Duchy of Lithuania confirm a real union, the united country is called the Polish-Lithuanian Commonwealth or the Republic of Both Nations.
1690 - Glorious Revolution: Battle of the Boyne as reckoned under Julian calendar.
1782 - American privateers attack Lunenburg, Nova Scotia.
1858 - The joint reading of Charles Darwin and Alfred Russel Wallace's papers on evolution to the Linnean Society.
1862 - Russian State Library is founded.
1862 - American Civil War: The Battle of Malvern Hill takes place, the final battle in the Seven Days Campaign, part of the George B. McClellan's Peninsula Campaign.
1863 - American Civil War: the Battle of Gettysburg begins.
1867 - The British North America Act, 1867 takes effect as the Constitution of Canada, creating the Canadian Confederation; John A. Macdonald sworn as first Prime Minister.
1870 - The United States Department of Justice formally comes into existence.
1873 - Prince Edward Island joins the Canadian Confederation.
1878 - Canada joins the Universal Postal Union.
1879 - Charles Taze Russell publishes the first edition of the religious magazine The Watchtower.
1881 - World's first international telephone call takes place between St. Stephen, New Brunswick, Canada, and Calais, Maine, United States.
1881 - General Order 70, the culmination of the Cardwell-Childers reforms of the British Army's organisation, came into effect.
1885 - United States terminates reciprocity and fishery agreement with Canada.
1890 - Canada and Bermuda linked by telegraph cable.
1892 - The Homestead Strike, a strike by the Amalgamated Association of Iron and Steel Workers against the Carnegie Steel Company, begins.
1898 - Spanish-American War: The Battle of San Juan Hill was fought in Santiago de Cuba.
1916 - World War I: First day on the Somme - On the first day of the Battle of the Somme 20,000 soldiers of the British Army are killed and 40,000 wounded.
1921 - Communist Party of China was founded.
1931 - United Airlines began service (as Boeing Air Transport)
1933 - Canadian Parliament suspends all Chinese immigration.
1935 - Regina, Saskatchewan police and Royal Canadian Mounted Police ambush strikers participating in On-to-Ottawa-Trek.
1942 - World War II: First Battle of El Alamein.
1942 - Australian Federal Govt becomes sole collector of Income Tax (State Income Tax Abolished).
1943 - Tokyo City merged with Tokyo Prefecture and was dissolved. Since then, no city in Japan has had the name "Tokyo." (Present-day Tokyo is not a city.)
1947 - British parliament passed India independence act. According to this took a decision for giving independence to India on August 15.
1948 - Quaid-i-Azam inaugrates Pakistan's central bank, the State Bank of Pakistan.
1957 - The International Geophysical Year begins (until December 31, 1958).
1958 - The Canadian Broadcasting Corporation links television broadcasting across Canada via microwave.
1958 - Flooding of the St. Lawrence Seaway begins.
1959 - The Party of the African Federation (PFA) holds its constitutive conference.
1960 - Independence of Somalia.
1960 - Ghana becomes a Republic and Kwame Nkrumah becomes its first President as Queen Elizabeth II of the United Kingdom ceases to be the Head of state.
1962 - Independence of Rwanda.
1962 - Independence of Burundi.
1963 - ZIP Codes are introduced for United States mail.
1963 - The British Government admits that former diplomat Kim Philby had worked as a Soviet agent.
1966 - First colour television transmission in Canada, from Toronto.
1967 - The European Community is formally created out of a merger with the Common Market, the European Coal and Steel Community, and the European Atomic Energy Commission.
1967 - Canada celebrates the 100th anniversary of the British North America Act, 1867.
1968 - The CIA's Phoenix Program is officially established.
1968 - The Nuclear non-proliferation treaty is signed in Washington, London and Moscow by sixty-two countries.
1968 - Formal separation of the United Auto Workers from the AFL-CIO.
1970 - President General Yahya Khan abolished One-Unit of West Pakistan restoring the provinces.
1972 - Andreas Baader, Jan-Carl Raspe and Holger Meins of the Red Army Faction are captured in Frankfurt after a shootout with the police.
1972 - First Gay Pride march in England
1976 - Portugal granted autonomy to Madeira.
1978 - Northern Territory (Aus) granted Self-Government.
1979 - Sony introduces the Walkman.
1980 - O Canada officially becomes the national anthem of Canada.
1983 - A North Korean Ilyushin Il-62M jet en route to Conakry Airport in Guinea crashes into the Fouta Djall Mountains in Guinea-Bissau, killing all 23 people on board.
1984 - The PG-13 rating is introduced by the MPAA.
1987 - American radio station WFAN in New York City is launched as the world's first all-sports radio station
1988 - Bologna, Italy: Quartetto Cetra's last concert after over forty years' musical career.
1990 - German re-unification: East Germany accepts the Deutsche Mark as its currency, thus uniting the economies of East and West Germany.
1991 - The Warsaw Pact is officially dissolved at a meeting in Prague.
1997 - The People's Republic of China resumes sovereignty over the city-state of Hong Kong, ending 156 years of British colonial rule.
1999 - The Scottish Parliament is officially opened by Queen Elizabeth on the day powers are officially transferred from the old Scottish Office in London to the new devolved Scottish Executive in Edinburgh.
2000 - Vermont's civil unions law goes into effect.
2000 - The Oresund Bridge, connecting Sweden and Denmark, opens for traffic.
2002 - The International Criminal Court is established to prosecute individuals for genocide, crimes against humanity, war crimes, and the crime of aggression.
2002 - A Bashkirian Airlines (flight 2937) Tupolev TU-154 and a DHL (German cargo) Boeing 757 collide in mid-air over Ueberlingen, southern Germany, killing 71.
2004 - Saturn Orbit insertion of Cassini-Huygens begins at 01:12 UT and ends at 02:48 UT.
2006 - The first operation of Qinghai-Tibet Railway in the People's Republic of China.
2007 - Smoking in England is banned in all public indoor spaces. With the ban already in force in Wales, Scotland and Northern Ireland, this means it is illegal to smoke in indoor public places anywhere in the UK. Ban also put into effect in Australia.
2007 - Prince William and Prince Harry throw a concert in memory of their mother the late Diana, Princess of Wales, on what would have been her 46th birthday.
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