Jak Zmierzyć Wszechświat

If you want to measure how big a stick is, you can use a ruler. Want to know how tall a windmill is? Don't waste time climbing to the top with a long measuring tape. Instead, use the old shadow trick--measure the length of a yardstick's shadow, then measure the windmill's shadow and use ratios to figure out the windmill's height. Even though the windmill is big and intimidating, you can find out its size while remaining safely on the ground. This is the first example in science author Kitty Ferguson's fine book *Measuring the Universe* , and it sets the reader's brain firmly on the right track for understanding. The topic here is measurement of faraway, distant, difficult things. Starting with Eratosthenes, who found a way of measuring the earth's circumference, and continuing through to modern astrophysicists' quest to measure the universe itself, Ferguson takes us on a full tour of the seemingly immeasurable. Readers are treated to enthusiastic chapters covering all the basic steps astronomers (dating back to Aristarchus of Samos) have taken to understand the arrangement of astronomical objects. How big are stars? Is that black hole moving toward us or away from us? Where is the edge of everything? And how big will the universe get before it stops expanding? You'll meet the men and women who have sought answers to these seemingly impossible questions in this accessible history. Ferguson brilliantly illuminates their personal quests and demonstrates the usefulness of each discovery in driving the next attempt to measure the universe. *\--Therese Littleton*