NASA reported earlier this week that a massive asteroid would skim the Earth's orbit on Dec. 11. The 1,082-foot space rock known as Asteroid 4660 Nereus is larger than the Eiffel Tower and will come within 4.6 million miles of Earth, putting it in the "potentially hazardous" category.
However, despite the slightly terrifying name of that category, Asteroid 4660 Nereus is expected to zip past Earth at 14,700 miles per hour at over 2.4 million miles away. That's 10 times the distance between the Earth and the moon, so this oncoming asteroid isn't a reason for concern. NASA labels anything that passes within 120 million miles of Earth a near-Earth object (NEO), and there are thousands of NEOs currently being tracked by scientists. Asteroid 4660 Nereus was first seen by astronomer Eleanor Helin in 1982 and passes by Earth fairly regularly. NASA and the Japanese space agency JAXA even considered "punching" it off-course with the Hayabusa spacecraft in order to prevent getting it from that close to Earth again.
Asteroid passings are a common concern in their field, though the public typically doesn't hear about them. Back in August of 2020, an asteroid actually passed much closer to the planet — just 1,830 miles over the Indian Ocean. Thankfully, that one was without incident as well. Scientists refer to the area of space around Earth's atmosphere as "the Apollo," designating which incoming objects to monitor.
Asteroids are made up of debris remaining from the formation of the solar system itself. They are mostly made of rock and other solid elements and can take odd shapes, though over time they tend to round out thanks to gravity. Asteroids pass Earth frequently, and scientists monitor for dangerous potential impacts at all times. NASA has much more information about these kinds of passages on its website.