Virgo Cluster Galaxy NGC 4731
http://apod.nasa.gov/apod/ap100429.html
This is a picture of NGC 4731 in the constellation Virgo. It is a barred spiral galaxy in the Virgo cluster of galaxies and is about 65 million light-years away. The Virgo cluster contains around 1300 but possibly up to 2000 galaxies. This cluster is the center of the Virgo Supercluster, which contains the Local Group. The newly-formed blue stars are visible in the spiral arms. The galaxy's arms are affected by the gravity of the elliptical galaxy NGC 4697. NGC 4731A is an irregular galaxy and is also in this picture. Young blue stars are also evident in this galaxy.
Friday, April 30, 2010
Thursday, April 29, 2010
Observations 4.1
4/15/10
Stargaze
8:00 PM - 9:00 PM
Conditions: cloudy
Moon: waxing crescent, very thin
Planets: Mercury and Venus were both visible near the Moon at sunset
Objects: M42, the Orion Nebula, M44, the star cluster in Cancer
Stars: the Alcor double and Mizar quadruple in Ursa Major
4/27/10
9:00 PM
Moon: waxing gibbous
Planets: Mars in Gemini, Saturn in Virgo
Constellations: Bootes, Cancer, Gemini, Leo, Ursa Major, Virgo
Stars: Arcturus, Castor, Denebola, Pollux, Regulus, Spica
4/29/10
10:00 PM
Star - Estimated Apparent Magnitude
eta Ursa Majorum - 2.2
beta Leonis - 2
gamma Leonis - 1.8
zeta Leonis - 3.5
epsilon Leonis - 3.2
lambda Leonis - 4
epsilon Virginis - 2.7
eta Virginis - 3.8
epsilon Corvi - 2.8
epsilon Bootis - 2.7
beta Bootis - 3.4
Stargaze
8:00 PM - 9:00 PM
Conditions: cloudy
Moon: waxing crescent, very thin
Planets: Mercury and Venus were both visible near the Moon at sunset
Objects: M42, the Orion Nebula, M44, the star cluster in Cancer
Stars: the Alcor double and Mizar quadruple in Ursa Major
4/27/10
9:00 PM
Moon: waxing gibbous
Planets: Mars in Gemini, Saturn in Virgo
Constellations: Bootes, Cancer, Gemini, Leo, Ursa Major, Virgo
Stars: Arcturus, Castor, Denebola, Pollux, Regulus, Spica
4/29/10
10:00 PM
Star - Estimated Apparent Magnitude
eta Ursa Majorum - 2.2
beta Leonis - 2
gamma Leonis - 1.8
zeta Leonis - 3.5
epsilon Leonis - 3.2
lambda Leonis - 4
epsilon Virginis - 2.7
eta Virginis - 3.8
epsilon Corvi - 2.8
epsilon Bootis - 2.7
beta Bootis - 3.4
Astronomer Biography 4
GENE AND CAROLYN SHOEMAKER
Eugene Shoemaker was born in 1928 in Los Angeles. As a boy he became interested in collecting and observing minerals and gemstones. He attended high school classes in elementary school, graduated from high school in two years, and attended the California Institute of Technology at the age of 16. He earned a master’s degree in geology in three years. In 1950 he married Carolyn Spellman, who would later help him with his work.
In 1948, he started inspecting various sources of uranium, such as volcanic vents and various craters, for the United States Geological Survey. He learned how to distinguish between craters created by underground forces and craters created by aboveground forces. He acquired a Ph.D. from Princeton for proving that the Meteor Crater near Flagstaff, Arizona had been caused by a meteor rather than a volcano, as was previously believed. At the Meteor Crater, he helped identify a unique mineral that was formed by great heat and pressure, which was called coesite. In 1960, while inspecting the Ries basin in Germany with his wife, Shoemaker found coesite, thereby proving that the 17-mile depression was actually a massive impact crater. He also showed that the craters on the moon were caused by comets and asteroids and not volcanoes.
Shoemaker started the Palomar Planet-Crossing Asteroid Survey in 1973. He and his colleague, Eleanor Helin, identified 70 asteroids that cross Earth’s orbit and could potentially collide with the planet. Shoemaker believed there could be up to 2000 of these objects. He supported the theory that an asteroid or comet caused the extinction of the dinosaurs.
Shoemaker had long dreamed of going to the moon, but this possibility was ruined when he was diagnosed with Addison’s disease in 1962. He played an important role in the eventual successes of the Apollo missions. He investigated the structure of the moon and helped improve geologic mapping techniques. He suggested ideal landing sites for the Apollo missions.
Carolyn started working with her husband at Mount Palomar when Eleanor Helin left in 1982. She learned how to use the telescope and helped Shoemaker search for asteroids in pictures of the sky. Shoemaker began to use a stereomicroscope, which was a geological tool, to help locate these objects. Carolyn would look through the microscope at pictures taken at different times to try to identify moving objects. Eugene and Carolyn discovered 32 comets and more than 800 asteroids.
Eugene’s friend David Levy joined the husband-and-wife team in 1988. In 1993, they took a photograph of part of the sky that included Jupiter at the time. When Carolyn looked at the picture on March 25, 1993, she discovered a comet, which was soon named Comet Shoemaker-Levy 9. This comet became famous, especially when it was announced in May of that year that it was on a collision course with Jupiter. The comet was caught by Jupiter’s gravity and pulled apart into 21 pieces, which then made visible impacts on the planet.
Eugene Shoemaker was a proponent for more funding to search for objects that could possibly collide with Earth. He predicted that a potentially devastating asteroid should hit Earth on average once every 100,000 years. Although he may be best-known for Comet Shoemaker-Levy 9, he studied the other planets and their moons and is recognized as the founder of astrogeology. Shoemaker died in a car crash in 1997. Some of his ashes were carried to the moon on the Lunar Prospector in 1999.
Bibliography
"Gene Shoemaker." Encyclopedia of World Biography. 2nd ed. Vol. 20. Detroit: Gale, 2004. 335-338. Gale Virtual Reference Library. Web. 29 Apr. 2010.
Marsden, Brian. "Eugene Shoemaker (1928-1997)." Web. < http://www2.jpl.nasa.gov/sl9/news81.html >.
"Shoemaker, Carolyn (1929–)." Dictionary of Women Worldwide: 25,000 Women Through the Ages. Ed. Anne Commire and Deborah Klezmer. Vol. 2. Detroit: Yorkin Publications, 2007. 1719. Gale Virtual Reference Library. Web. 29 Apr. 2010.
"USGS Astrogeology: Eugene M. Shoemaker." USGS Astrogeology Science Center. Web. < http://astrogeology.usgs.gov/About/People/GeneShoemaker/ >.
Eugene Shoemaker was born in 1928 in Los Angeles. As a boy he became interested in collecting and observing minerals and gemstones. He attended high school classes in elementary school, graduated from high school in two years, and attended the California Institute of Technology at the age of 16. He earned a master’s degree in geology in three years. In 1950 he married Carolyn Spellman, who would later help him with his work.
In 1948, he started inspecting various sources of uranium, such as volcanic vents and various craters, for the United States Geological Survey. He learned how to distinguish between craters created by underground forces and craters created by aboveground forces. He acquired a Ph.D. from Princeton for proving that the Meteor Crater near Flagstaff, Arizona had been caused by a meteor rather than a volcano, as was previously believed. At the Meteor Crater, he helped identify a unique mineral that was formed by great heat and pressure, which was called coesite. In 1960, while inspecting the Ries basin in Germany with his wife, Shoemaker found coesite, thereby proving that the 17-mile depression was actually a massive impact crater. He also showed that the craters on the moon were caused by comets and asteroids and not volcanoes.
Shoemaker started the Palomar Planet-Crossing Asteroid Survey in 1973. He and his colleague, Eleanor Helin, identified 70 asteroids that cross Earth’s orbit and could potentially collide with the planet. Shoemaker believed there could be up to 2000 of these objects. He supported the theory that an asteroid or comet caused the extinction of the dinosaurs.
Shoemaker had long dreamed of going to the moon, but this possibility was ruined when he was diagnosed with Addison’s disease in 1962. He played an important role in the eventual successes of the Apollo missions. He investigated the structure of the moon and helped improve geologic mapping techniques. He suggested ideal landing sites for the Apollo missions.
Carolyn started working with her husband at Mount Palomar when Eleanor Helin left in 1982. She learned how to use the telescope and helped Shoemaker search for asteroids in pictures of the sky. Shoemaker began to use a stereomicroscope, which was a geological tool, to help locate these objects. Carolyn would look through the microscope at pictures taken at different times to try to identify moving objects. Eugene and Carolyn discovered 32 comets and more than 800 asteroids.
Eugene’s friend David Levy joined the husband-and-wife team in 1988. In 1993, they took a photograph of part of the sky that included Jupiter at the time. When Carolyn looked at the picture on March 25, 1993, she discovered a comet, which was soon named Comet Shoemaker-Levy 9. This comet became famous, especially when it was announced in May of that year that it was on a collision course with Jupiter. The comet was caught by Jupiter’s gravity and pulled apart into 21 pieces, which then made visible impacts on the planet.
Eugene Shoemaker was a proponent for more funding to search for objects that could possibly collide with Earth. He predicted that a potentially devastating asteroid should hit Earth on average once every 100,000 years. Although he may be best-known for Comet Shoemaker-Levy 9, he studied the other planets and their moons and is recognized as the founder of astrogeology. Shoemaker died in a car crash in 1997. Some of his ashes were carried to the moon on the Lunar Prospector in 1999.
Bibliography
"Gene Shoemaker." Encyclopedia of World Biography. 2nd ed. Vol. 20. Detroit: Gale, 2004. 335-338. Gale Virtual Reference Library. Web. 29 Apr. 2010.
Marsden, Brian. "Eugene Shoemaker (1928-1997)." Web. < http://www2.jpl.nasa.gov/sl9/news81.html >.
"Shoemaker, Carolyn (1929–)." Dictionary of Women Worldwide: 25,000 Women Through the Ages. Ed. Anne Commire and Deborah Klezmer. Vol. 2. Detroit: Yorkin Publications, 2007. 1719. Gale Virtual Reference Library. Web. 29 Apr. 2010.
"USGS Astrogeology: Eugene M. Shoemaker." USGS Astrogeology Science Center. Web. < http://astrogeology.usgs.gov/About/People/GeneShoemaker/ >.
Friday, April 23, 2010
APOD 4.3
Saturn's Moons Titan and Dione from Cassini
http://apod.nasa.gov/apod/ap100420.html
Saturn has 62 moons with confirmed orbits. This is a picture, taken by the Cassini spacecraft, of Titan and Dione. Titan is Saturn's largest moon; it is larger in volume than Mercury. It has an atmosphere and its surface is obscured by clouds. Both Titan and Dione are composed of water ice and rocky material. In the picture, both moon are in the gibbous phase because they are close to each other. The Cassini-Huygens spacecraft was launched in 1997 and entered into orbit around Saturn in 2004. The Huygens probe landed on Titan in 2005.
http://apod.nasa.gov/apod/ap100420.html
Saturn has 62 moons with confirmed orbits. This is a picture, taken by the Cassini spacecraft, of Titan and Dione. Titan is Saturn's largest moon; it is larger in volume than Mercury. It has an atmosphere and its surface is obscured by clouds. Both Titan and Dione are composed of water ice and rocky material. In the picture, both moon are in the gibbous phase because they are close to each other. The Cassini-Huygens spacecraft was launched in 1997 and entered into orbit around Saturn in 2004. The Huygens probe landed on Titan in 2005.
Friday, April 16, 2010
APOD 4.2
Bright Points on the Quiet Sun
http://apod.nasa.gov/apod/ap100416.html
This is a picture of granules on the Sun's solar surface. These granules are caused by convection currents of plasma from the convection zone of the Sun. The center of each granule is the top of the rising column of plasma; surrounding each granule is a darker area of less hot descending plasma. The light spots in these darker areas are caused by high-density magnetic fields that create holes into the deeper, hotter areas.
http://apod.nasa.gov/apod/ap100416.html
This is a picture of granules on the Sun's solar surface. These granules are caused by convection currents of plasma from the convection zone of the Sun. The center of each granule is the top of the rising column of plasma; surrounding each granule is a darker area of less hot descending plasma. The light spots in these darker areas are caused by high-density magnetic fields that create holes into the deeper, hotter areas.
Thursday, April 8, 2010
APOD 4.1
Millions of Stars in Omega Centauri
http://apod.nasa.gov/apod/ap100331.html
This is a picture of the globular cluster Omega Centauri, also known as NGC 5139. It was discovered by Edmund Halley in 1677, who did not at the time realize what it was. John William Herschel recognized it as a globular cluster in the 1830s. It contains around 10 million stars and is about 12 billion years old. It orbits the center of the Milky Way in the halo of the galaxy; it is the largest and brightest known globular cluster to do so. Because it is different from most other globular clusters, it is thought to have a different origin; it is speculated that it is the remnant of the core of a dwarf galaxy that was incorporated into the Milky Way.
http://apod.nasa.gov/apod/ap100331.html
This is a picture of the globular cluster Omega Centauri, also known as NGC 5139. It was discovered by Edmund Halley in 1677, who did not at the time realize what it was. John William Herschel recognized it as a globular cluster in the 1830s. It contains around 10 million stars and is about 12 billion years old. It orbits the center of the Milky Way in the halo of the galaxy; it is the largest and brightest known globular cluster to do so. Because it is different from most other globular clusters, it is thought to have a different origin; it is speculated that it is the remnant of the core of a dwarf galaxy that was incorporated into the Milky Way.
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