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Cosmic Horizons

January 14, 2014

Cosmic Horizons: Astronomy at the Cutting Edge

This book piqued my interest because I’ve always been a fan of Neil deGrasse Tyson, but I never took the time to read one of his books. So at the Denver Public Library, I searched for books written by him and found and checked out a few. Cosmic Horizons is divided into six(6) sections and edited by both Steven Soter and Neil deGrasse Tyson. My favorite aspect of this book is how it went above and beyond to point out and give credit to the lesser known contributors to major astronomical discoveries. So I’ll focus this blog post on those unpopular scientists that were so important and/or ahead of their time. Another note: the diagrams and astronomical pictures in this book wonderfully illustrated the subjects.

Section One: Solar Systems (not just ours)

This section was subdivided around the topics: Europa’s chances of supporting simple life, the Kuiper belt, the sources of comets in our solar system both long period and short period comets, detecting extrasolar planets, and interplanetary hazard impacts. Finally, a profile on a German physicist who first suggested the true nature of meteorites. On to Jupiter’s moon Europa, as a place in our solar system where simple life could be supported under the miles of ice perhaps a briny ocean warmed by internal planetary friction caused by Jupiter’s tidal gravitational pull. In 1992, David Jewitt and Jane Luu found the first member of the theorized Kuiper belt. Gerard Kuiper predicted the belt’s existance in 1951. Since that time, Pluto was reclassified from planet to the largest Kuiper Belt Object (KBO) due to it following the same orbit as the belt. The two primary sources of comets in the solar system are the Oort cloud (which spherically surrounds our solar system and extends nearly half way to the nearest star) and the Kuiper belt (orbit of Pluto). The method and results to date of attempts to detect extra-solar planets are described briefly. Finally, interplanetary impact hazards and the effects of such an impact relative to other destructive forces.

Ernst Chladni – the father of meteoritics. A German physicist published a small book in 1794 suggesting that the iron rocks crashing into Earth were from extraterrestrial origin. He started gathering information by interviewing eyewitness accounts and based on those accounts calculated that the speed of meteors were too great to be explained by Earth’s gravitational force.

Section Two: Stars

This section covers the types of stars, and also their lifecycle from birth to death. Stellar nurseries are large nebulas which formed by collecting remnants of material ejected by other dying stars. The next subsection discusses the fact that the formation of our solar system (a circumstellar disk) is quite common in the observable universe. So could that solar system formation commonality lead to similar planets in a habitable zone for life?

Friedrich Bessel, a German astronomer (1784-1846). Discovered the parallax method for measuring stellar distances.

Cecilia Payne – “There is no joy more intense than that of coming upon a fact that cannot be understood in terms of currently accepted ideas.” Although, she developed the process of “reading” a star’s spectra of wavelengths to determine its composition and temperature, she was never properly acknowledged for her accomplishment due to sexism in her time.

Section Three: Galaxies

Edwin Hubble’s realization that redshift in light from galaxies is proportional to distance away from us: the farther away the galaxy the redder it appears, also because the faster it’s moving away from us. Observing galaxies and their gravitational properties unveils a startling disproportionate gravitational effect for the visible matter, which implies the existence of “dark matter”. The observed mass vs the gravitational effect of mass differs by a factor of TEN.

Vera Rubin – “In a spiral galaxy, the ratio of dark-to-light matter is about a factor of ten. That’s probably a good number for the ratio of our ignorance-to-knowledge. We’re out of kindergarten, but only in about third grade.”
Her research around the spirals in a spiral galaxy and the speed of rotation could not be explained if most of the mass of a galaxy was at its visible core. Instead, 90% of the true mass of a galaxy must be dark matter to have the spirals rotate as quickly as the center stars.

John Michell – an English country parson, announced in 1783 the idea of a “black hole” – a region of space so dense where gravity is so strong even light could not escape. Michell conceived of the apparatus to measure the gravitational constant of attraction between two masses.

Section Four: Universe

The age of the universe is estimated to be around 13.8 billion years old, but the edge of the observable universe does not extend that far in light years, because at the time of the big bang the universe was not transparent as it is today. The edge of the observable universe is the cosmic background radiation which is the remnant of the big bang.

Fritz Zwicky – 1898-1974 – Swiss American astronomer who first conceived of supernovas, neutron stars, dark matter, and gravitational lensing by galaxies. Noted for an abrasive personality by colleagues, he was quoted as saying “Astronomers are spherical bastards. No matter how you look at them they’re just bastards.” Tremendous contributor to astronomy yet virtually unknown to the public because of the scientific community’s dislike of his attitude.

Ole Roemer – 1676 – Danish astronomer became the first person to measure the speed of light.

Olbers’ Paradox: Why is the sky dark at night? Interesting explanation in the book.

Georges Lemaitre – 1931 – posited the idea of a big bang creation of the universe.

Section Five: Life in the Universe

This section explored finding life in unexpected places on Earth, and how it might also be found in unexpected places on less hospitable planets like Jupiter’s Europa. Exploration of what it would require to terraform Mars, a planet with many of the core elements required for planet life (photosynthesis) and simple life and the time required for more terraforming to produced more habitable conditions for more complex life. Also discussed, the possibility of microbial life being transferred from one celestial body to another by impacts that eject material into space that can be captured by another celestial body thereby “seeding” it with life.

Carl Sagan – “Ask courageous questions. Do not be satisfied with superficial answers. Be open to wonder and at the same time subject all claims to knowledge, without exception, to critical scrutiny. Be aware of human fallibility. Cherish your species and your planet.”

Section Six: Technical Frontier

Gamma ray and neutrino detection, computer modeling, SETI and space telescopes.

Lyman Spitzer – crucial in building the Hubble Space Telescope. Nazi V-2 rockets made the idea of a space telescope a real possibility.

A very enjoyable book that covered the facts as well as the history and the exceptional individuals that worked so hard for these discoveries.


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