Galileo at 400
Galileo Galilei by Giusto Sustermans
Four hundred years ago Galileo Galilei, a 45-year old teacher of mathematics, physics and astronomy at the University of Padua in what is today Italy, learned of the development in the Netherlands of optical instruments that magnified distant objects. Based on this general knowledge he invented his own telescope and began to make astronomical observations.
Even with his first crude 3-power instrument Galileo could see things that no one until his time had been able to observe. He focused first on the Moon and discovered that it was not smooth as people had thought but disfigured with craters and mountains just like the Earth.
Impressed by this observation, Galileo built an improved scope, this one with 20-power capability. With it he turned his attention to another bright light in the sky, the planet Jupiter. Near the planet he noticed four objects that he first took to be stars but, observing them and recording their positions for a month, he realized that they were satellites revolving around the planet. In honor of Galileo, those four largest satellites of Jupiter are called the Galilean moons. Galileo's contemporary, Simon Marius, who may have discovered them independently, named them Io, Europa, Ganymede and Callisto. With more powerful instruments astronomers have since their time discovered 60 additional Jupiter satellites.
The Galilean moons were the first celestial objects discovered by telescope and, far more important, they were the first objects that were observed to orbit a body that was neither the earth nor the sun. This was strong evidence opposing the then current belief that the Earth was the center of the Universe with all celestial objects revolving around it. Galileo's observations indirectly supported the hypothesis of the Polish astronomer, Nicolaus Copernicus, that the Sun and not the Earth was the center of our Solar System.
This was evidence that was difficult to reject because anyone could observe it with a similar telescope.
Eventually this discovery was to bring Galileo into confrontation with powerful leaders of the Catholic Church. He was tried, convicted of heresy and sentenced to house arrest for the rest of his life. It was not until 1992 that the Church finally officially apologized for its condemnation of Galileo and his insistence on the Copernican system.
In honor of Galileo's 1609 discovery, this year is being celebrated as the International Year of Astronomy. As what it has described as its "Cornerstone Project," a group of organizations including the International Astronomical Union and the United Nations, is making available a 20 to 50-power telescope for the remarkable price of $15 plus $8.95 shipping.
This is not one of those telescopes offered in discount houses that are designed only to separate you from your money. Instead it is a high-quality instrument developed by a team of leading astronomers, optical engineers, and science educators called the Galileoscope that is easily assembled in five minutes. (For better viewing the scope easily attaches to any standard tripod.)
The project grew out of the astronomers' concern that not everyone has a telescope, especially in less developed parts of the world. Thus, one feature of the web-based order form at <www.galileoscope.org> is the opportunity to order one or more extra scopes for donations to those who cannot afford them.
The Galileoscope is augmented by educational activities and related materials for use by classroom teachers, planetarium presenters, astronomy-club members, and anyone else eager to share the treats of the telescopic sky with others.
Events celebrating IYA2009 are also taking place around the world, including some here in Buffalo. Today the Buffalo Astronomical Association (BAA) is sponsoring "Solar SUNday" on the roof of the Buffalo Museum of Science. Visitors will have an opportunity to observe the sun with its sunspots and fiery prominences through safely filtered telescopes. On April 10th at its regular 7 p.m. museum meeting, BAA members will provide a hands-on look at various types of telescopes. Members of the public are encouraged to bring their own scopes to this event so that they can learn to use them more effectively. Then on May 2nd BAA will celebrate Astronomy Day 2009 with daytime activities at the Buffalo Museum of Science followed by Public Night at its Beaver Meadow Observatory during the evening.-- Gerry Rising