Near-Earth Objects (NEOs) are asteroids and comets whose elliptical orbits bring them within 1.3 astronomical units (AU) of the Sun—roughly 195 million kilometers—potentially crossing Earth's orbital path. These cosmic wanderers are classified into three main groups: Atens (orbits smaller than Earth's), Apollos (Earth-crossing with larger orbits), and Amors (approaching but not crossing Earth's orbit).</p><p>Currently, astronomers have catalogued over 33,000 NEOs, with new discoveries added weekly through dedicated sky surveys like NASA's NEOWISE mission. The most famous NEO is probably 99942 Apophis, a 370-meter asteroid that will make a remarkably close approach in 2029, passing within 31,000 kilometers of Earth—closer than many satellites. Another notable example is asteroid Bennu, visited by NASA's OSIRIS-REx mission, which returned samples to Earth in 2023.</p><p>While Hollywood dramatizes asteroid impacts, the statistical risk remains low. Objects larger than 140 meters—capable of regional destruction—are designated as Potentially Hazardous Objects (PHOs) when they approach within 7.5 million kilometers of Earth. The 1908 Tunguska event, likely caused by a 50-meter object, flattened 2,000 square kilometers of Siberian forest, demonstrating NEOs' potential impact. Today's sophisticated tracking systems provide decades of advance warning for any threatening objects.