NASA’s
Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE)
telescope has detected 97 heretofore-unknown objects in our solar
system, 10 of which have been characterized as “potentially
hazardous objects” (PHOs).
Of the 97
objects, 28 were near-Earth objects (NEOs), five were comets and 64
were asteroids in the Asteroid Belt.
PHOs are
defined as space objects at least 100 meters in diameter that may
come within 4.6 million miles of Earth. Any smaller and they're
likely to disintegrate in the atmosphere, any farther away and
they'll simply miss Earth entirely. NASA defines them as asteroids
and comets that are guided "by the gravitational attraction of
the planets in our solar system into orbits that allow them to enter
Earth's neighborhood."
These
objects, mostly asteroids, have a chance to hit Earth and cause
regional or even global devastation within the next 100 years. Since
the 1990s, the number of PHOs on record has increased tenfold as a
result of improvements in telescopes and observation.
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