This book continues our exploration of cosmology, the science of the universe as a whole.
Here we examine one of the greatest challenges and most important accomplishment of astronomy and cosmology: measuring the distance to remote celestial bodies. We will discover how astronomers used their wits and centuries of meticulous observations to precisely measure the size and evolution of our universe.
Cosmic distance measurement has a critical role in cosmology. Almost everything we claim to know about our universe — its size, its expansion, changes in expansion rate, its age, and its history — depends on measuring cosmic distances. Thus distance measurement has long been, and continues to be, one of the greatest challenges in astronomy and cosmology.
In an ideal world (or universe), a magical instrument would tell us the distance to at any celestial body we wished. Unfortunately, there’s no such thing in this world. Astronomers can measure positions across the sky with extreme precision. They can also precisely measure the composition of celestial objects, and how fast they are moving toward or away from us. But, when asked about that twinkling little star, astronomers still struggle with “...how I wonder where you are.”
Here we examine one of the greatest challenges and most important accomplishment of astronomy and cosmology: measuring the distance to remote celestial bodies. We will discover how astronomers used their wits and centuries of meticulous observations to precisely measure the size and evolution of our universe.
Cosmic distance measurement has a critical role in cosmology. Almost everything we claim to know about our universe — its size, its expansion, changes in expansion rate, its age, and its history — depends on measuring cosmic distances. Thus distance measurement has long been, and continues to be, one of the greatest challenges in astronomy and cosmology.
In an ideal world (or universe), a magical instrument would tell us the distance to at any celestial body we wished. Unfortunately, there’s no such thing in this world. Astronomers can measure positions across the sky with extreme precision. They can also precisely measure the composition of celestial objects, and how fast they are moving toward or away from us. But, when asked about that twinkling little star, astronomers still struggle with “...how I wonder where you are.”
