He said scientists have identified 95% of asteroids more than a half-mile in diameter -- the kind that threaten human existence if they strike Earth, like the six-mile-wide one believed to have wiped out dinosaurs 65 million years ago -- and found none on a collision course with the planet.

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The WHO's "Phases of Pandemic Alert, " which has been in existence for five years, characterizes phase 5 as a human-to-human spread of the virus into at least two countries in one WHO region, signaling that a pandemic is imminent.

CNN: WHO raises pandemic alert to second-highest level

The horror of nuclear conflict may make its occurrence unlikely, but the very existence of nuclear weapons leaves the human race ever at the brink of self-destruction, particularly if the weapons fall into the wrong hands.

WHITEHOUSE: VP Biden: The Path to Nuclear Security

It is solely through dialogue and peaceful co-existence that the achievement of the world vision for sustainable development, protection of human rights and alleviation of poverty will become possible.

UNESCO: Cyprus &

To be a middle-middle-class American in the early 21st century is to occupy the 99.99 percentile of human existence, in terms of nutrition, wealth and ease.

FORBES: Digital Rules