The Milky Way

You are inside a galaxy right now. Every star you have ever seen with the naked eye is part of it. The smear of light called the Milky Way that stretches across the sky on dark summer nights is not something out there. It is the galaxy we live in, seen from the inside, edge-on, looking along the plane of the disk. This book is a complete tour of it.The Milky Way explains what our galaxy actually is, how we know what we know about a structure we have never stepped outside of, and what the latest research has revealed about its history and its future. You will learn how Harlow Shapley used the distribution of globular clusters in 1918 to discover that the Sun is not near the center of the galaxy but 26,000 light-years from it, in the outer suburbs. You will understand the supermassive black hole at the galactic center, Sagittarius A*, which was directly imaged for the first time in 2022 after 27 years of tracking the orbits of individual stars around it. You will follow the Gaia satellite's billion-star survey and the extraordinary discoveries it made possible, including the identification of the Gaia-Enceladus merger, a collision between the early Milky Way and a galaxy the size of the Large Magellanic Cloud that happened 8 to 11 billion years ago and built much of the stellar halo we see today.Twelve chapters cover the full picture: the disk, bar, spiral arms, galactic center, dark matter halo, interstellar medium, star formation history, chemical evolution, globular clusters, satellite galaxies, and the future collision with Andromeda that will begin in roughly 4.5 billion years and transform both galaxies into a single elliptical called Milkomeda. Every chapter is built on real observations and real science, written for adult readers who want depth without a textbook.Part of the Stars and Galaxies Adult Series.

You are inside a galaxy right now. Every star you have ever seen with the naked eye is part of it. The smear of light called the Milky Way that stretches across the sky on dark summer nights is not something out there. It is the galaxy we live in, seen from the inside, edge-on, looking along the plane of the disk. This book is a complete tour of it.The Milky Way explains what our galaxy actually is, how we know what we know about a structure we have never stepped outside of, and what the latest research has revealed about its history and its future. You will learn how Harlow Shapley used the distribution of globular clusters in 1918 to discover that the Sun is not near the center of the galaxy but 26,000 light-years from it, in the outer suburbs. You will understand the supermassive black hole at the galactic center, Sagittarius A*, which was directly imaged for the first time in 2022 after 27 years of tracking the orbits of individual stars around it. You will follow the Gaia satellite's billion-star survey and the extraordinary discoveries it made possible, including the identification of the Gaia-Enceladus merger, a collision between the early Milky Way and a galaxy the size of the Large Magellanic Cloud that happened 8 to 11 billion years ago and built much of the stellar halo we see today.Twelve chapters cover the full picture: the disk, bar, spiral arms, galactic center, dark matter halo, interstellar medium, star formation history, chemical evolution, globular clusters, satellite galaxies, and the future collision with Andromeda that will begin in roughly 4.5 billion years and transform both galaxies into a single elliptical called Milkomeda. Every chapter is built on real observations and real science, written for adult readers who want depth without a textbook.Part of the Stars and Galaxies Adult Series.