Nor can astronomers say when the next catastrophic impact will occur. They only know that it will happen, sooner or later. The history of Earth's encounters with asteroids remains largely mysterious to scientists. They can't even agree whether a huge space rock that hit Mexico's Yucatan Penninsula 65 million years ago killed off the dinosaurs or not. However, now anyone with a passing interest in the fate of the planet can remove some of the mystery regarding the effects of the next collision. A new University of Arizona web page allows visitors to plug in a hypothetical space rock's size, the visitor's distance from the impact site, and other parameters to generate an outline of devastation.
But be warned: Removing the mystery invites a bit of terror over the hypothetical slams, bangs, fireballs, falling skies and rushing winds generated by a giant impact, reports news.yahoo.com
According to BBC scientists have launched an online calculator that works out the effects of an asteroid colliding with Earth. Users can choose the size and type of space object and the distance they are standing from the impact site.
The program then calculates the scale of the fireball, the size of the crater left behind and even even whether the impact will ignite your clothes.
It is designed to make it easier for scientists to work out the effects of different types of space collision.
The program estimates the scale of four different environmental effects following an impact: thermal radiation given out, earthquakes that are generated, debris thrown out by the collision and the air blast - a wave of distortion in the air caused by the energy of the impact.
It also works out the damage to buildings and how many trees will be blown down in the wake of the strike. Should the end zoom into Earth on a comet's tail, Web surfers now can calculate if they have time only to cuss before bursting into flames, or have a couple of minutes to seek shelter from a downpour of hot rock. Many scientists believe the long-term effects of such an asteroid strike could lead to the end of civilization as the atmosphere changes and crops fail globally, Melosh said.
Going for the big one, a 20-kilometer iron asteroid augering into Los Angeles would ignite most of the plants in Tucson and badly burn most skin. Three minutes later, the desert would shake violently, and five minutes after that, hot rock would rain from the sky and bury Tucson under 47 feet of granules.
A similar blast killed the dinosaurs and occurs every 1.3 billion years.
Melosh, an expert in near-Earth objects, got the idea to develop the Web site in the late 1990s, when the media peppered him with questions about hypothetical effects of some asteroids that came close to Earth, inform tucsoncitizen.com