Near-Earth objects (NEOs) are celestial bodies, such as asteroids and comets, that come close to Earth's orbit. They are classified based on their proximity to our planet, with some having orbits that bring them within 1.3 astronomical units (AU) of the Sun. NEOs can vary in size, ranging from small boulders to large bodies several kilometers wide. Scientists monitor NEOs to assess any potential threat they may pose to Earth. Organizations like NASA track these objects to predict their paths and determine if any could collide with our planet. Understanding NEOs helps improve planetary defense strategies and ensures the safety of Earth.