When there are two truths Published on September 21, 2021September 20, 2021 by fivecolorssandt@icloud.com Aristotle vs. Ptolemy We point out an uneasy tension beneath an apparent unity. Read More
Twelve quarters Published on March 30, 2021March 28, 2021 by fivecolorssandt@icloud.com Where the wind blows A poetic phrase has an unexpected scientific source. Read More
Four elements, four humors Published on December 1, 2020December 1, 2020 by fivecolorssandt@icloud.com Before the revolution We conclude that it can be useful to teach something that is actually wrong. Read More
Saving the phenomena Published on June 5, 2018June 1, 2018 by fivecolorssandt@icloud.com Fixed stars, part II The Middle Ages were a hotbed of astronomical controversy in Europe. Read More