Rogue Asteroids and Doomsday Comets pdf epub mobi txt 电子书 下载 2026

Could a giant asteroid or comet crash into the Earth and destroy life as we know it? Many astronomers who formerly discredited the risks are now convinced there is a grave danger. In Rogue Asteroids and Doomsday Comets, astronomer Duncan Steel explores the scientists' fascinating and often chilling findings.

Director of one of three global asteroid and comet search programs, Steel is one of the world's leading experts. He tells the intriguing story of the scientific detection work that pieced together mounting evidence to uncover a stunning history of impacts. Massive comet and asteroid impacts scarred our planet frequently in the past—a comet was almost surely responsible for the extinction of the dinosaurs. Recent advances in telescope tracking technology show at least 2,000 objects now orbiting the Earth that are large enough to hit with the force of a nuclear weapon. Based on the best calculations, it is certain that the Earth will sooner or later find itself on a disastrous collision course once again.

In the event of a collision, evidence suggests outcomes such as three-mile-high ocean waves capable of obliterating coastal communities worldwide, a massive conflagration and a cloud of dust and ash blocking all sunlight and making agriculture impossible. With consummate authority, Steel explains and evaluates these prospects and the plans researchers have proposed for the search and destruction of oncoming celestial bodies, including Edward Teller's provocative call for a nuclear bomb.

Rogue Asteroids and Doomsday Comets is a compelling account of the threat posed to life on Earth from outer space, and of scientists' response. Killer comets and asteroids populate the cosmos in greater numbers than we have ever imagined. But for the first time, humankind is in a position to prevent calamity. This book makes a compelling case that to waste that opportunity would be both perilous and foolhardy.

"A chilling and utterly convincing account of a cosmic menace that must not be ignored any longer. Duncan Steel writes with authority and credibility. This book is a welcome challenge to the scientific prejudice against catastrophism." —Paul Davies, author of The Mind of God

Evidence of Earth's encounters with killer comets and asteroids . . .

An enormous crater 180 kilometers across was recently identified in Mexico's Yucatan Peninsula. The asteroid that created it 65 million years ago must have been larger than 20 kilometers. Was this gargantuan collision the cause of a global environmental disaster that led to the extinction of the dinosaurs? Fossil evidence shows that 900f the terrestrial biomass was incinerated about the time of the asteroid's impact. Did an asteroid crash spark a fireball that literally saw the Earth go up in flames?

In 1908, a much smaller asteroid exploded in the atmosphere over the remote Tunguska region of Siberia. The blast, estimated at 20 megatons—2,000 times the power of the bombs dropped on Hiroshima and Nagasaki, leveled vast expanses of forest and ignited fires that burned out of control. The explosion's mighty thunderclap was audible over 400 miles away, and throughout Europe the night sky glowed unnaturally bright

Could both Stonehenge and the pyramids of Egypt have been constructed to observe and commemorate a period of phenomenal meteor storms and asteroid detonations produced by a burst of activity in the Taurid Complex 4,500 to 5,000 years ago? Author Duncan Steel examines the evidence indicating rogue asteroids and doomsday comets may have been behind these and other ancient phenomena.