Tonight, at 1:27 p.m. (Friday morning), an asteroid called 2023 BU the size of a truck, it will approach the Earth more than any other nearby object recorded so far. Despite NASA’s insistence that it does not pose a danger to Earth, the space rock will come to be only 3,600 km from the Earth’s surface, the same altitude at which geosynchronous satellites orbit the planet.
As NASA explains in a announcementeven if 2023 BU ‘changed its mind’ and ended up crashing into us, it would turn into a huge fireball and would disintegrate in the atmosphere without causing damage. Only some small fragments, those that managed to survive the entrance, would manage to reach the ground in the form of meteorites. The North American space agency has estimated that the size of the asteroid is between 3.5 and 8.5 meters.
2023 BU was discovered just a few days ago (January 21) by amateur astronomer Gennadiy Borisov, who in August 2019 was the first to observe the interstellar comet 2I/Borisov.
The finding was quickly confirmed by the Minor Planet Center (MPC), the international organization that measures and confirms the position of small celestial bodies, and the data was automatically published on the confirmation page for near-Earth objects. After collecting a sufficient number of observations, the MPC announced the discovery. Just three days later, dozens of observations had already been made by various observatories around the world, helping astronomers better calculate the orbit of 2023 BU.
This image from NASA’s Scout system shows how the trajectory of asteroid 2023 BU (in red) will be deflected by Earth’s gravity after the early morning encounter. In green, the orbits of the geosynchronous satellites. The gray ring corresponds to the orbit of the Moon
As soon as its existence was known, NASA’s Scout impact risk assessment system, maintained by the Center for Near-Earth Object Studies (CNEOS) at the Jet Propulsion Laboratory (JPL) in Pasadena, in southern California, analyzed the data from the MPC confirmation page and quickly predicted what the unusual encounter would be like. CNEOS calculates all known near-Earth asteroid orbits to provide assessments of potential impact risks in support of NASA’s Planetary Defense Coordination Office (PDCO).
orbit change
As Davide Farnocchia, the JPL navigation engineer who developed Scout, explains, the system “quickly ruled out 2023 BU as an impactor, and despite the few available observations, was able to predict that the asteroid would come extraordinarily close to Earth. In fact, this is one of the closest approaches ever recorded for a known near-Earth object.”
As NASA explains, the asteroid will come so close to us that its trajectory around the Sun will change drastically due to the gravity of our planet. Before meeting us, its orbit around the Sun lasted 369 days and was almost circular. But from now on that orbit will lengthen and become more oval, roughly halfway between the orbits of Earth and Mars. From now on, it will take 425 days to complete one orbit around the Sun.