Topline
An asteroid the size of a building will pass close by Earth later tonight, though experts say it doesn’t pose any threat to the planet.
Key Facts
A 250-foot asteroid will pass by Earth on Friday, coming within 4.1 million miles of the planet—about 17 times further than the Moon—while traveling about 26,719 miles per hour, according to NASA’s California-based Jet Propulsion Laboratory.
NASA classifies all asteroids that come within 4.6 million miles of Earth, and are larger than 492.126 feet (150 meters) as a “potentially hazardous object,” so although this asteroid is expected to make a close approach, it doesn’t meet the size requirement to be deemed potentially hazardous, and “poses no hazard to our planet,” a JPL official told Forbes.
The last time this asteroid, called 2024 CJ8, passed by Earth was in 2020, and the next time will be on Aug. 29, 2028, though this year’s approach is the closest it’s ever been to Earth, according to NASA’s estimates.
It’s expected to pass by Earth at 8:25 p.m. EDT, and although it won’t be visible to the naked eye, NASA offers a virtual asteroid tracker to watch where in the solar system asteroids are in real time.
Big Number
More than 1.3 million. That’s how many asteroids NASA estimates are in the solar system.
Key Background
Asteroids are rocky objects made up of the leftover remains from when the solar system was formed about 4.6 billion years ago, according to NASA. They’re smaller than planets, but orbit the Sun like planets do. In more recent years, NASA has upped its efforts to protect Earth from coming into contact with asteroids. The agency performed its first Double Asteroid Deflection Test in 2022, which changed the orbit of an asteroid. It sent a spacecraft into space, which hit the asteroid and shortened its orbit by a little over 30 minutes. In another effort to defend against potential asteroid approaches, NASA also sent a spacecraft on the mission OSIRIS-REx, which explored a large near-Earth asteroid named Bennu. The spacecraft collected samples from Bennu and dropped them off in the Utah desert in September 2023, and the findings suggest Bennu may be a fragment of an ancient ocean world. More research is being done on Bennu because scientists think it may collide with Earth in 2182. Though the exact area is unknown, Bennu has a one-in-2,700 chance of hitting a Texas-sized portion of Earth in 2182.
Surprising Fact
The spacecraft that was a part of OSIRIS-Rex is now on a new mission called OSIRIS-APEX, in which it will study the physical changes of another asteroid named Apophis. The spacecraft won’t return until 2029.
Tangent
Asteroid 2024 CJ8 won’t be the only one passing by Earth this weekend. It will be accompanied by the much smaller asteroid 2024 EQ, which is 69 feet wide, making it the size of an airplane. It’s expected to come within an even closer approach to Earth, reaching about 1.65 million miles of the planet. Asteroid 2024 EK4 is also expected to pass by Earth this weekend. The bus-size asteroid is 32 feet wide, and is predicted to come within 2.5 million miles of Earth.
Further Reading
NASA scientists calculated the exact date an asteroid could hit Earth with the force of at least 24 nuclear bombs. Thankfully, it’s a long way off. (Business Insider)
Next Five Asteroid Approaches (Jet Propulsion Laboratory)
Dr. Thomas Hughes is a UK-based scientist and science communicator who makes complex topics accessible to readers. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
