Edwin Hubble Edwin Hubble Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an American astronomer. He played a crucial role in establishing the fields of extragalactic astronomy and observational cosmology and is regarded as one of the most important astronomers of all time. Hubble discovered that many objects previously thought to be clouds of dust and gas and classified as "nebulae" were actually galaxies beyond the Milky Way. He used the strong direct relationship between a classical Cepheid variable's luminosity and pulsation period (discovered in 1908 by Henrietta Swan Leavitt) for scaling galactic and extragalactic distances. Hubble provided evidence
The Post Card: From Socrates to Freud and Beyond The Post Card: From Socrates to Freud and Beyond The Post Card: From Socrates to Freud and Beyond () is a 1980 book by French philosopher Jacques Derrida. It is a "satire of epistolary literature." After "Glas" (1974), it is sometimes considered Derrida's most "literary" book, and continues the critical engagement with psychoanalysis first signaled in "Freud and the Scene of Writing" from Derrida's "Writing and Difference" (1967). The first half of the book, titled "Envois" (sendings), contains a series of love letters addressed by Derrida to an unnamed loved one. In one of the letters, dated 6 June 1977,