Pre-publication of the book by Neil deGrasse Tyson and Donald Goldsmith - Wishevoke

Pre-publication of the book by Neil deGrasse Tyson and Donald Goldsmith

The progress that has been made in understanding the universe is illuminated by the book of astrophysicists. Neil deGrasse Tyson And Donald Goldsmith “The Beginning – 14 Billion Years of Cosmic Evolution,” the revised version of which will be published on April 3 by “Dioptra” Publications, translated by Christodoulos Litharis.

The two astrophysicists approach the development of the universe from their personal perspective and refer to recent developments around the universe cosmology and they write about what they believe and what they believe science cannot answer. With an informative and sometimes humorous tone, the two scientists “travel” the reader through the vast universe.

The publication covers important recent discoveries, such as the more than 5,000 exoplanets that shed light on the origins and possibilities of life elsewhere in our Milky Way, and cites data from new ground- and space-based observatories that have fundamentally changed what we know about the expanding universe. Universe. Neil deGrasse Tyson is astrophysical and author of, among other things, the international bestseller Astrophysics for the Fast. Since 1996 he has been director of the Hayden Planetarium at the American Museum of Natural History in New York. He hosts the Emmy Award-winning podcast StarTalk and is co-founder of the corresponding publication StarTalk Sports Edition. He has been awarded honorary doctorates 21 times, received the Social Contribution Medal from the US National Academy of Sciences and the Distinguished Service Medal from NASA. The asteroid 13123 Tyson was named in his honor.

Donald Goldsmith is an astrophysicist who has taught at Berkeley, California and other universities. He has written over twenty books and has been honored by the American Astronomical Society for his contribution to the popularization of astronomy.

Here is a pre-release of the book:

DISCOVER GALAXIES

Two and a half centuries ago, just before the English astronomer Sir William Herschel built the world’s first truly large telescope, the known universe consisted only of the stars, the sun and moon, the planets, some moons of Jupiter and Saturn, etc., some dark objects and the Milky Way, forming a milky streak in the night sky. Obtuse objects, whose scientific name is nebula, from the Latin word nebulae, meaning “cloud”, are objects of indeterminate shape, such as the Crab Nebula in the constellation Taurus and the Andromeda Nebula, which appears to lie among the stars in the constellation Andromeda.

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Herschel’s telescope had a mirror 48 inches in diameter – an unprecedented size for 1789, the year it was completed. The beam frame that supported and controlled it made it an unwieldy instrument, but when Herschel pointed it toward the sky, he could immediately see the countless stars that made up our galaxy. Using this 48-inch telescope, as well as a smaller and more flexible telescope, Herschel and his sister Caroline created the first comprehensive catalog of northern deep sky nebulae. Sir John – the son of William Herschel – continued the family tradition by expanding his father and aunt’s catalog of northern objects, recording some 1,700 dark objects from the southern hemisphere during an extended stay at the Cape of Good Hope at the southern tip of Africa were visible from. In 1864, he compiled a collection of known deep sky objects, A General Catalog of Nebulae and Clusters of Stars, which included over 5,000 entries. Despite this large amount of data, no one at the time knew the true identity of the nebulae, their distance from Earth, or the differences between them. However, the 1864 catalog offered the possibility of classifying nebulae morphologically – i.e. according to their shape. Astronomers referred to nebulae with a spiral shape as “spiral nebulae,” nebulae with a roughly elliptical shape as “elliptical nebulae,” and various irregularly shaped nebulae—that were neither spiral nor elliptical—as “irregular nebulae.” They ended up calling the nebulae, which appeared small and round, like a telescope image of a planet, “planetary nebulae,” a terminological error that always confuses newcomers to astronomy.

For most of its history, astronomy called a spade a spade, using descriptive research methods very similar to those of botany. Using long catalogs of stars and dark objects, astronomers looked for patterns and classified objects accordingly. And it was a very logical step. Since childhood, most people arrange things according to their appearance and shape without anyone telling them to. But this approach has its limits. The Herschel family had always assumed that since many of the dark objects in the night sky were about the same size, all nebulae must be about the same distance from Earth. So for them it was simply a good and correct scientific method to apply the same classification rules to all nebulae.

The bad thing is that the assumption that all nebulae are at similar distances turned out to be completely wrong. Nature is elusive, even cunning. Some of the nebulae categorized by Herschel are not much further apart than the stars and are therefore relatively small (if a width of a few trillion kilometers can be considered “relatively small”). It turns out that some others were much further away, so they must be larger than dark objects relatively close to us to appear the same size in the sky.

So the lesson is that at some point you have to stop fixating on the appearance of something and start asking what it is. Fortunately, by the late 19th century, thanks to advances in science and technology, astronomers were able to do just that and no longer easily categorize the contents of the universe. This change led to the birth of astrophysics, the useful application of the laws of physics to astronomical situations.

At the same time that Sir John Herschel published his extensive catalog of nebulae, a new scientific instrument, the spectroscope, was being used in nebula research. The spectroscope’s only job is to split the light into a rainbow of its individual colors. These colors and the features they contain not only reveal minute details about the chemical composition of the light source, but also reveal the movement of the light source as it approaches or moves away from the Earth, due to the Doppler effect described in Chapter 5.

Spectroscopy finally revealed something remarkable: the spiral nebulae that dominate outside our galactic track are almost all moving away from Earth, and at extremely high speeds. In contrast, all planetary nebulae, like most irregular nebulae, move at relatively slow speeds – some towards us and others away from us. Had there been a cataclysmic explosion at the center of the galaxy, ejecting only the spiral nebulae? If so, then why hasn’t anyone given in? Did we see the destruction at some point? Despite advances in photography that led to faster photographic emulsions and allowed astronomers to measure the spectra of ever-dimmering nebulae, the exodus continued and questions remained unanswered.

Most advances in astronomy, as in other sciences, have come from the introduction of better technology. In the early 1920s, another key instrument appeared on the scene: the impressive 100-inch Hooker Telescope at the Mount Wilson Observatory near Pasadena, California. In 1923, the American astrophysicist Edwin P. Hubble used what was then the largest telescope in the world to find a special type of star, a Cepheid variable, in the Andromeda Nebula. Variable stars of all kinds vary in brightness according to known patterns; Cepheid variables, named after the prototype of the class, a star in the constellation Cepheus, are all extremely bright and therefore visible from great distances. As their brilliance varies in discernible cycles, patience and perseverance will reveal more and more to the attentive viewer. Hubble had found some of these variable Cepheids in our galaxy and calculated their distances, but to his surprise, the Cepheid he found in Andromeda was much fainter than the others.

The most likely explanation for this darkness was that the new Cepheid variable and the Andromeda Nebula in which it exists are much further away than our galaxy’s Cepheids. Hubble realized that this made the Andromeda Nebula so distant that it couldn’t possibly belong to the stars of the constellation Andromeda or anywhere in our galaxy – nor could it have been blown away along with its spiral siblings in a catastrophic accident.

That meant something shocking. Hubble’s discovery showed that the spiral nebulae were independent star systems, large and full of stars like our own galaxy. In the words of philosopher Immanuel Kant, Hubble had shown that dozens of “island universes” must lie outside our own star system, since the object in Andromeda was only the first in a list of the best-known spiral nebulae.

The Andromeda Nebula was actually the Andromeda Galaxy.

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