Protecting Earth from asteroids(Read article summary)
Asteroid impacts with Earth are a near-certainty, scientists say. The question is: What, if anything, should we do to track asteroids and protect Earth from them?
Last week, a meteorite reportedly crashed through the roof of a doctor's office in Virginia. No one was hurt when, traveling at some 200 miles per hour, a half-pound space rock smashed into an examination room, breaking into pieces on the concrete floor. But the incident highlighted the not-insignificant threat posed by asteroids and ice balls from space.
The consequences of a sufficiently large asteroid or comet strike could be catastrophic, which is why you're reading this in a blog about the environment:. Depending on size, an amount of energy equivalent to tens of thousands and even many millions of nuclear bombs would be released on impact. Such a strike could be disastrous not just for civilization, but for the planet's entire web of life.
If it landed in the ocean, the impact would send walls of water in all directions, inundating continental margins. If it struck land, it could ignite continent-wide fires.
And while the destruction would be immediate around the strike zone, the problems would likely become global in the aftermath: Dust injected into the atmosphere could block sunlight. Photosynthetic organisms would stop growing. Everything else that depended on them would suffer the consequences of a reduced food supply. Mass starvation would ensue.
The last asteroid strike on this scale is widely thought to have contributed to the dinosaurs' end 65 million years ago. The asteroid, which left a 110-mile-wide crater off Mexico's Yucatan Peninsula, was only six miles in diameter, roughly the size of Manhattan Island. But three-quarters of life on Earth disappeared.
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