Two tiny asteroids sneaked safely past Earth last weekend, only to be discovered hours after they'd buzzed our planet. Asteroids 2018 NX and 2018 NW zipped past our blue-green orb at distances of just 72,000 miles and 76,000 miles, respectively. That's about one-third of the distance from the Earth to the moon. Scientists think the asteroids both stretched between about 16 feet and 50 feet in diameter. That's relatively small for near-Earth asteroids. Astronomers at an observatory on the Palomar Mountain range in California spotted both space rocks on Sunday, according to the International Astronomical Union's Minor Planet Center. Although they passed our planet in quick...