One of my recent reads is a non-fiction "The Universe", by Isaac Asimov. First published in mid-sixties, its contents, possibly, could be found deprecated by the professional cosmologist. I am not one, and did learn a lot.
Also, being almost sixty years removed from the text puts an inspiring impression on a reader: some topics, mostly related to the interplanetary missions or more capable telescopes, were put by an author in a "what if" form, or in a "potentially, some day" form, but a modern reader can remember them as realized projects, as accomplished facts: the discovery of planets orbiting other stars, rover missions on Mars, unmanned interstellar spacecraft.
Another source of inspiration is a the very gist of the book: the narrative revolves on how the humanity learned to explore space around them, starting in Mediterranean, figuring out the shape and size of the Earth, then building the models and understanding of planets, then galaxies, eventually expanding the scope to, ever escaping from us, the frontier of the Universe.
Beginning
Anyone who lives near the sea, has little chance of avoiding observing the Earth curvature. Departing ships, before becoming invisible due to distance, disappear on the horizon hull first, as if disappearing behind a hill. Eratosthenes was the first to measure Earth curvature (and the size), and to do that with impressive precision. 17 centuries later, Columbus used this estimate to motivate his Atlantic expedition to investors.
Planets & Stars
A technique called parallax allowed to obtain planet distances in the Kepler's model of Solar system. It was found that this technique cannot be applied trivially to measuring the distances to the stars, even with the better telescopes, built by 18th century. To measure the distance to a star via parallax one needs to tease out the displacement terms due to the aberration, and proper motion of the star.
Milky Way & Beyond
Another way of determining interstellar distances besides the parallax is brightness-based. The distant variable stars serve as a benchmark to calibrate against. Other variable objects also exist, judged to be at a much greater distance from us. These were established to be other galaxies, like Andromeda, which was a start of this discovery. Now it, with our Milky way, along with many others, comprise an intergalactic structure called the Local Group, which seems a fitting name for the expanded version of humanity's realm.
Red Shift & Quasars
Big Bang Theory via the Hubble constant, cuts out the remotest parts of the Universe from us, those which recede at speeds approaching the speed of light, thus preventing any interaction with them. The book closes on quasars, which I failed to understand properly at a moment, but hope to return to them in due time.
Conclusion
Shortly after the "Universe" I've read the "Cosmos" by Carl Sagan, which is 10 years younger a book. While expecting to learn more about advances in astronomy from this fresher publication, I found Cosmos to be less technical and more hand-wavy (though poetic in places, to be fair). I think my next astronomy read will be by Kip Thorne.
Goodbye until then, reader (Ah, this blogger talks to themselves).
