Foscarini sent a copy of his book to Bellarmine, who replied in a letter of April 12, 1615.  Galileo is mentioned by name in the letter, and a copy was soon sent to him. After some preliminary salutations and acknowledgements, Bellarmine begins by telling Foscarini that it is prudent for him and Galileo to limit themselves to treating heliocentrism as a merely hypothetical phenomenon and not a physically real one. Further on he says that interpreting heliocentrism as physically real would be "a very dangerous thing, likely not only to irritate all scholastic philosophers and theologians, but also to harm the Holy Faith by rendering Holy Scripture as false." Moreover, while the topic was not inherently a matter of faith, the statements about it in Scripture were so by virtue of who said them—namely, the Holy Spirit. He conceded that if there were conclusive proof, "then one would have to proceed with great care in explaining the Scriptures that appear contrary; and say rather that we do not understand them, than that what is demonstrated is false." However, demonstrating that heliocentrism merely "saved the appearances" could not be regarded as sufficient to establish that it was physically real. Although he believed that the former may well have been possible, he had "very great doubts" that the latter would be, and in case of doubt it was not permissible to depart from the traditional interpretation of Scriptures. His final argument was a rebuttal of an analogy that Foscarini had made between a moving Earth and a ship on which the passengers perceive themselves as apparently stationary and the receding shore as apparently moving. Bellarmine replied that in the case of the ship the passengers know that their perceptions are erroneous and can mentally correct them, whereas the scientist on the Earth clearly experiences that it is stationary and therefore the perception that the Sun, moon and stars are moving is not in error and does not need to be corrected.
The device irradiates samples with alpha particles and maps the spectra of X-rays that are re-emitted for determining the elemental composition of samples.  Curiosity 's APXS was developed by the Canadian Space Agency .  MacDonald Dettwiler (MDA) , the Canadian aerospace company that built the Canadarm and RADARSAT , were responsible for the engineering design and building of the APXS. The APXS science team includes members from the University of Guelph , the University of New Brunswick , the University of Western Ontario , NASA , the University of California, San Diego and Cornell University .  The APXS instrument takes advantage of particle-induced X-ray emission (PIXE) and X-ray fluorescence , previously exploited by the Mars Pathfinder and the Mars Exploration Rovers .