Edwin Hubble

Edwin Powell Hubble (Marshfield, November 20, 1889 - San Marino, California, September 28, 1953) was one of the most important American astronomers of the century XX, famous mainly for having demonstrated in 1929 the expansion of the universe by measuring the redshift of distant galaxies. Hubble is considered the father of observational cosmology, although his influence on astronomy and astrophysics touches many other fields.

Although he began studying law at Oxford University, he returned to the field of astronomy when he joined the Yerkes Observatory at the University of Chicago, where he earned a Ph.D. in physics in 1917. Returning from his service in World War I, In 1919, he began work at the new Mount Wilson Observatory, where he had access to a 10-inch telescope, then the most powerful in the world. At the observatory, he worked alongside Milton Humason. Today there is a satellite (Hubble Space Telescope) that is named "Hubble" in his honor.

Discoveries

The Universe goes beyond the Milky Way

Edwin Hubble's early work at the Mount Wilson Observatory focused on the study of what were then known as nebulae. By then, the shape and size of these were known reasonably well, but they were all thought to be part of our galaxy.

It was clear that some nebulae were in the galaxy and were basically starlit gas within it. In 1924 Hubble succeeded in distinguishing stars in the Andromeda Nebula. Using Leavitt's period-luminosity law, he was able to come up with an estimate of its distance, which he calculated to be 1.5 million light-years, eight times farther than the most remote known stars (it would later be underestimated). In the years that followed, he repeated his success nebula after nebula, making it clear that the galaxy was one among a host of "isolated micro universes."

The expansion of the Universe

After half a century since Huggins recorded the redshift of the spectrum of the star Sirius, he had recorded multiple redshifts and blueshifts of various objects in the universe. In 1929, Hubble published an analysis of the radial velocity, relative to the Earth, of the nebulae whose distance he had calculated, stating that although some extragalactic nebulae had spectra indicating that they were moving toward Earth, the vast majority showed shifts toward the Earth. red that could only be explained under the assumption that they were moving away. He even discovered that there was a direct relationship between the distance of a nebula and its receding speed.

Hubble concluded that the only consistent explanation for the recorded redshifts was that, apart from a "local group" of nearby galaxies, all the extragalactic nebulae were receding and that the further away they were, the faster they receded. This only made sense if the universe itself, including the space between galaxies, was expanding. This led the astronomer to elaborate together with Milton Humason the postulate of Hubble's law about the expansion of the universe.

Other discoveries

Hubble discovered the asteroid (1373) Cincinnati on August 30, 1935. Also around this time he wrote The Observational Approach to Cosmology and The Realm of the Nebulae.

Controversy over discovery

In the November 9, 2011 edition of the Nature magazine, researcher Mario Livio, an astronomer at the Space Telescope Science Institute in Baltimore (Maryland), United States, explained that he located in the archives of the Royal Society of London a letter from 1931, which makes it clear that Hubble was not the first to discover, in 1929, the expansion of the Universe, but the Belgian astronomer and priest Georges Lemaître in 1927, to whom he owes Now take credit for the discovery. On the other hand, Mario Livio declared that he believed that Hubble was not responsible for a lack of ethics, since the translation of the article by the astronomer Lemaître into English, published in 1931, had the fundamental paragraphs and calculations of 1927 omitted, but did not because of the editor's fault, or to favor Hubble, as has always been believed, but by a decision of Lemaître himself, perhaps due to his modesty, because he knew that his own article was not known, for having published it in French, or else because his 1927 data was already out of date in 1931.

According to other reliable data from that time, Hubble would have plagiarized the idea, "on hearing it from two or three scientists", one of them probably being Georges Lemaître when he returned "in 1927-1928" from an international congress, apparently in Holland, from which he arrived "very excited" with the news.

According to all this, not only should Georges Lemaître be returned the honor of discovering and demonstrating the expansion of the Universe, but it would also be proven, eighty years later, that the accusations of plagiarism that came from numerous media at the time against Hubble they actually had a point. Therefore, it is likely that some laws, paradigms and discovery of related phenomena by Hubble will be revised, leaving his other merits intact.

Final Stage

George Hale, the founder and director of the Carnegie Institution's Mount Wilson Observatory near Pasadena, California, offered him a job where he remained until his death in 1953 after suffering a stroke. Before his death, Hubble was the first to use the Hale telescope at the Palomar Observatory.

Eponymy

• The Hubble lunar crater carries this name in his memory.
• The asteroid (2069) Hubble also commemorates its name.
• The Hubble Space Telescope was baptized with this name in his honor.