Galileo and Orbits

Galileo the Astronomer

The Telescope an interesting invention. Its importance lies in demonstrating that, through instrumentation, one can observe things with far more precision and depth than can be attained using only human senses. The Universe became a whole lot larger.

But here is Galileo's sales pitch on this new invention (in the year 1608):

This is a thing of inestimable benefit for all transactions and undertakings, maritime or terrestrial, allowing us at sea to discover at a much greater distance than usual the hulls and sails of the enemy, so that for 2 hours and more we can detect him before he detects us.

(Research is still frequently funded this way).

Galileo's first set of documented nighttime observations were on November 30, 1609, when he pointed the telescope at the moon.

With his Telescope Galileo discovered that the celestial objects were marred by imperfections (oh say it ain't so) -- (by late 1610 these observations could and were reproduced by others):

• That the moon was non-uniform and had blemishes. Other observers could reproduce this result:
  

• That the sun had spots

• That venus showed phases

• That there were a lot more stars out there than could be seen with the naked eye Why was this an important discovery?

• That saturn had something wrong in its appearance.

• That Jupiter had 4 moons in orbit about it
  Galileo's observations of the satellites of Jupiter
  

  This is the most important set of observations made by Galileo. He did this in January of 1609 and in a mere 15 nights of observing (interrupted by two completely cloudy nights) he deduced that Jupiter had 4 objects in orbit about it.

  He published this result on March 13, 1609.

  Well of course this was unsettling and a threat to institutions/ideas that supported our special place in the Universe. Some other notables, clergy, etc looked through the telescope and pretended not to see the moons. Some refused to look through the telescope.

  One scientist of the day summed the situation up as follows:

  These satellites of Jupiter are invisible to the naked eye, and therefore exercise no influence on the Earth, and therefore would be useless and therefore do not exist.

  Wow ...

  
  The history of Galileo vs the Catholic Church is a fascinating one because there is still controversy remaining as to the church's stance on science and Galileo's responsibility for getting arrested. From the Catholic Church point of view, several church figures supported science and improved upon Galileo's findings (indeed there were clergy who supported Copernican theory and Galileo) and of course there were several who condemned Galileo and his work. But they do paint Galileo as an ambitious and obnoxious individual who was basically an ass to his Church supporters and less mentally gifted than the Jesuit astronomers who argued with him. And after bruising a few more egos in the church, Galileo lost a lot of support, including Pope Urban who also originally did support him but not the Copernican Universe. The Pope wanted him to speak about other cosmologies - only known to god (and the pope - how convenient) that were responsible for the observations.
  

  Of course, this isn't science and Galileo wasn't having it. The events leading to his arrest occurred because he provoked the Church with his personality. Galileo probably didn't have the best people skills and he also didn't have "the why" behind observed phenomena. However, the real issue here is that the Church was picking which data to follow and not follow. The data demonstrated that other objects such as Jupiter are orbited by smaller objects forming their own mini solar system. Thus, the Earth couldn't be at the center of the Universe. A copernican Universe wasn't perfect, but it was much better than the Brahe model.

  Bottom line: You always go by the observations. It is what it is until better data come along to prove or disprove it.