Galileo a bad scientist?
This article in Scientific American suggests that, although Galileo Galilei quite famously had a more accurate understanding of the Solar System than was generally accepted at the time, he reached these conclusions in spite of his observations and not because of them. He simply chose the theory that he preferred instead of the one that evidence supported. In other words, he was a bad and dishonest scientist who turned out to be correct only by sheer luck!
The argument is based on the way stars would have appeared in his telescope. The laws of physics predict that, due to the phenomenon of Diffraction, a point source of light (like a distant star) should appear as a tiny disk, surrounded by faint concentric circles. This was not known in Galileo’s day, so the only reasonable explanation he could have had for the disc was that the stars were close enough to make out through a telescope. Therefore, he should have concluded that Tycho Brahe had come up with the correct model of the universe (A modified version of the classical Ptolemaic system, which put Earth at the centre of the universe and everything else moving around it – Brahe suggested that Earth was at the Centre, the Sun revolved around the Earth, and everything else revolved around the two together).
The problem, however, is that the authors seem to have forgotten all of Galileo’s other discoveries which contradicted the predictions of the Ptolemy’s and Brahe’s models. He saw phases on Venus (Proving that Venus orbits the Sun), he saw satellites orbiting Jupiter (Proving Ptolemy wrong, in that not all motion is centered around the earth), and made countless other observations laying the foundations for modern astronomy. He had a giant stack of evidence supporting the theory we now know to be true, and one observation which seemed to contradict just one premise of the Copernican system (The distance of the stars). To say that this makes him a sloppy scientist is something of a low blow!