Close Flyby of a Large Asteroid or Comet
While small objects pass near Earth regularly, large ones come closer less frequently. Every thousands, or millions of years, we’ll get lucky enough to see an asteroid or comet pass close enough to Earth that it makes itself known. This happens once every 7,500 years.
Even though it would seem like an incredible experience to watch a nearby comet, if it gets too close, the results may be disastrous. Apparently, “Fortunately, according to NASA, asteroids larger than about 330 feet (100 m) in diameter are only expected to strike Earth roughly once every 10,000 years. Meanwhile, nearly apocalyptic asteroids, those larger than about 0.6 miles (1 km) wide, are expected to strike our planet once every several hundred thousand years or so.” Let’s hope that’s long after our time here on Earth (Astronomy).