October 23, 2009
Saturn expert explains planet
Scientist discusses moons, atmosphere of ringed planetAstrophysicist Greg Black spoke about the planet Saturn at a meeting of the Institute for Lifelong Learning (IFLL) on Wednesday, Oct. 21.
Black, a Selinsgrove native, returned to his hometown to lecture an audience that included IFLL members, his parents and a few of his childhood teachers. Black drove to Selinsgrove from Charlottesville, Va., where he is a research scientist at the University of Virginia.
According to his page on the University of Virginia's Web site, astro.virginia.edu/~gb3n, Black specializes in planetary science, near-earth asteroids and radar interferometry techniques.
He was asked to speak at the IFLL meeting by the organization's president, Joe Herb, in honor of the International Year of Astronomy (IYA).
According to the IYA?Web site, astronomy2009.org/general, the celebratory year is "a global effort [...] to help the citizens of the world rediscover their place in the Universe through the day and nighttime sky, and thereby engage a personal sense of wonder and discovery."
Black spoke about the planet Saturn, its rings, moons and the singular atmosphere of the planet's largest moon.
"When you study something, you often end up with more questions about it than answers," Black said of his studies.
The planetary research Black engages in uses a 300-foot wide, ground-based radio telescope in Charlottesville. He said the radio telescope emits waves toward the rings of the planet that then bounce back and are read by the telescope.
Saturn is about one billion miles from the earth, according to Black, and though the waves travel at the speed of light, it takes two hours for them to bounce back to the telescope.
"Those waves tell us the location of the rings and how fast they are spinning," Black said. "They are made up of ice particles ranging in size from a regular snowball to about the size of [Degenstein Theater]."
The waves are used to determine the location and rotation of the rings that encircle the planet. Black said that they rotate independently of each other at various speeds.
The rings also vary in cleanliness, he said. Those closer to the planet have less dust particles than those further from it.
According to Black, Saturn is composed mainly of frozen liquid natural gas and maintains a temperature of negative three hundred degrees Fahrenheit.
The largest of the trillions of moons rotating around Saturn is named Titan. Black said Titan is 50 percent larger than the Earth's moon and is the largest moon of all the planets in the Milky Way Galaxy.
Black showed pictures of the orange-colored moon taken by ion cameras aboard the Cassini Spacecraft, a NASA craft that was launched to orbit and explore the planet.
According to Black, the moons of Saturn come together and can be observed by people like him as "little laboratories."
He explained that NASA has photographic evidence of other galaxies beginning to form, which occurs because space matter becomes "dominated by gravity." The movement of Saturn's moons and the magnetic push and pull of the planet can be applied to the newly-formed galaxies.
"We're interested in how this planet does what it does," Black said.
Black earned a bachelor's degree in physics from the Massachusetts Institute of Technology and a doctorate degree in astronomy and Cornell University.
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