Facts About the Solar System

Facts About the Solar System Welcome to the solar system! This is where youll find the Sun, the planets, and humanitys sole home in the Milky Way Galaxy. It contains planets, moons, comets, asteroids, one star, and worlds with ring systems. Although astronomers and skygazers have observed other solar system objects in the sky since the dawn of human history, it has only been in the past half-century that theyve been able to explore them more directly with spacecraft. Historical Views of the Solar System Long before astronomers could use telescopes to look at objects in the sky, people thought that the planets were simply wandering stars. They had no concept of an organized system of worlds orbiting the Sun. All they knew were that some objects followed regular paths against the backdrop of the stars. At first, they thought these things were gods or some other supernatural beings. Then, they decided that those motions had some effect on human lives. With the advent of scientific observations of the sky, those ideas vanished.   The first astronomer to look at another planet with a telescope was Galileo Galilei. His observations changed humanitys view of our place in space. Soon, many other men and women were studying the planets, their moons, asteroids, and comets with scientific interest. Today that continues, and there are currently spacecraft doing many solar system studies. So, what else have astronomers and planetary scientists learned about the solar system?   Solar System Insights A journey through the solar system introduces us to the Sun, which is our nearest star. It contains an amazing 99.8 percent of the mass of the solar system. The planet Jupiter is the next most-massive object and it comprises two and a half times the mass of all the other planets combined. The four inner planets- tiny, cratered Mercury, cloud-shrouded Venus (sometimes called Earths Twin), temperate and watery Earth (our home), and reddish Mars- are called the terrestrial or rocky planets. Jupiter, ringed Saturn, mysterious blue Uranus, and distant Neptune  are called gas giants. Uranus and Neptune are so cold and contain a great deal of icy material, and are often called the ice giants.   The solar system has five known dwarf planets. They are called Pluto, Ceres, Haumea, Makemake, and Eris. The New Horizons mission explored Pluto on July 14, 2015, and is on its way out to visit a small object called 2014 MU69. At least one and possibly two other dwarf planets exist in the outer reaches of the solar system, although we do not have detailed images of them. There are probably at least 200 more dwarf planets in a region of the solar system called the Kuiper Belt (Pronounced KYE-per Belt.) The Kuiper Belt extends out from the orbit of Neptune and is the realm of the most distant worlds known to exist in the solar system. It is very distant and its objects are likely icy and frozen. The outermost region of the solar system is called the Oort Cloud. It probably has no large worlds but does contain chunks of ice that become comets when they orbit very close to the Sun. The Asteroid Belt is a region of space that lies between Mars and Jupiter. It is populated with chunks of rocks ranging from small boulders up to the size of a big city. These asteroids are left over from the formation of the planets.   There are moons throughout the solar system. The only planets that do NOT have moons are Mercury and Venus. Earth has one, Mars has two, Jupiter has dozens, as do Saturn, Uranus, and Neptune. Some of the moons of the outer solar system are frozen worlds with watery oceans beneath the ice on their surfaces.   The only planets with rings that we know of are Jupiter, Saturn, Uranus, and Neptune. However, at least one asteroid called Chariklo also has a ring and planetary scientists recently discovered a tenuous ring around the dwarf planet Haumea.   The Origin and Evolution of the Solar System Everything that astronomers learn about solar system bodies helps them understand the origin and evolution of the Sun and planets. We know they  formed about 4.5 billion years ago. Their birthplace was a cloud of gas and dust that slowly contracted to make the Sun, followed by the planets. The comets and asteroids are often considered the leftovers of the birth of the planets.   What astronomers know about the Sun tells us that it will not last forever. Some five billion years from now, it will expand and engulf some of the planets. Eventually, it will shrink down, leaving behind a very changed solar system from the one we know of today.

Anna Arnold Hedgeman, Civil Rights Activist, Feminist

Anna Arnold Hedgeman, Civil Rights Activist, Feminist article edited with additions by Jone Johnson Lewis Dates: July 5, 1899Â  -Â  January 17, 1990Known for: African-American feminist; civil rights activist; founding member of NOW Anna Arnold Hedgeman was a civil rights activist and an early leader in the National Organization for Women. She worked throughout her life on issues such as education, feminism, social justice, poverty and civil rights. A Pioneer for Civil Rights Anna Arnold Hedgemans lifetime of accomplishments included many firsts: First black woman to graduate from Hamline University (1922) - the university now has a scholarship named for herFirst black woman to serve on a New York City mayoral cabinet (1954-1958)First black person to hold a Federal Security Agency position Anna Arnold Hedgeman was also the only woman on the executive committee that organized Martin Luther King, Jr.s famous March on Washington in 1963. Patrik Henry Bass called her instrumental in organizing the march and the conscience of the march in his book Like A Mighty Stream: The March on Washington August 28, 1963 (Running Press Book Publishers, 2002). When Anna Arnold Hedgeman realized there were going to be no female speakers at the event, she protested the minimal recognition of women who were civil rights heroes. She succeeded in persuading the committee that this oversight was a mistake, which led eventually to Daisy Bates being invited to speak that day at the Lincoln Memorial. NOW Activism Anna Arnold Hedgeman served temporarily as the first executive vice-president of NOW. Aileen Hernandez, who had been serving on the Equal Employment Opportunity Commission, was elected executive vice-president in absentia when the first NOW officers were selected in 1966. Anna Arnold Hedgeman served as temporary executive vice-president until Aileen Hernandez officially stepped down from the EEOC and took the NOW position in March 1967. Anna Arnold Hedgeman was the first chair of NOWs Task Force on Women in Poverty. In her 1967 task force report, she called for a meaningful expansion of economic opportunities for women and said there were no jobs or opportunities for women at the bottom of the heap to move into. Her suggestions included job training, job creation, regional and city planning, attention to high school dropouts and an end to the ignoring of women and girls in federal job and poverty-related programs. Other Activism In addition to NOW, Anna Arnold Hedgeman was involved with organizations including the YWCA, the National Association for the Advancement of Colored People, the National Urban League, the National Council of Churches Commission on Religion and Race and the National Council for a Permanent Fair Employment Practices Commission. She ran for Congress and president of the New York City Council, drawing attention to social issues even when she lost the elections. A 20th Century Life in the United States Anna Arnold was born in Iowa and grew up in Minnesota. Her mother was Mary Ellen Parker Arnold, and her father, William James Arnold II, was a businessman. The family was the only black family in Anoka, Iowa, where Anna Arnold grew up. Â  She graduated from high school in 1918, and then became the first black graduate of Hamline University in Saint Paul, Minnesota. Unable to find a teaching job in Minnesota where a black woman would be hired, Anna Arnold taught in Mississippi at Rust College. She could not accept living under Jim Crow discrimination, so she returned north to work for the YWCA. She worked at black YWCA branches in four states, ending up finally in Harlem, New York City. In New York in 1933, Anna Arnold married Merritt Hedgeman, a musician and performer. Â   During the Depression, she was a consultant on racial problems for the Emergency Relief Bureau of New York City, studying near-slavery conditions of black women who worked in domestic service in the Bronx, and studying Puerto Rican conditions in the city. Â  When World War II began, she worked as a civil defense official, advocating for black workers in war industries. In 1944 she went to work for an organization advocating for fair employment practices. Â  Unsuccessful at getting fair employment legislation passed, she returned to the academic world, working as an assistant dean for women at Howard University in New York. In the 1948 election, she was executive director of the presidential re-election campaign for Harry S Truman. After he was reelected, she went to work for his government, working on issues of race and employment. Â  She was the first woman and the first African American to be part of a mayoral cabinet in New York City, appointed by Robert Wagner, Jr., to advocate for the poor. As a laywoman, she signed a 1966 black power statement by black members of the clergy which appeared in the New York Times. In the 1960s she worked for religious organizations, advocating for higher education and racial reconciliation. Â  It was in her role as a part of religious and womens communities that she advocated strongly for the participation of white Christians in the 1963 March on Washington. She wrote the books The Trumpet Sounds: A Memoir of Negro Leaership (1964) and The Gift of Chaos: Decades of American Discontent (1977).Anna Arnold Hedgeman died in Harlem in 1990.