The U.S. space agency NASA says a small asteroid will pass very close to Earth Thursday, just 3,600 kilometers from our planet's surface, well within the orbit of most geosynchronous satellites.

In a release on its website, NASA says the object, known as 2023 BU, poses no threat to the Earth. The agency says even if it entered the atmosphere it would turn into a fireball and largely disintegrate harmlessly, with some bigger debris potentially reaching the surface as small meteorites.

NASA says the object - just 3.5 to 8.5 meters across - represents one of the closest passes by a near-Earth object ever recorded. It is expected to pass over the southern tip of South America at 7:27 p.m. EST (12:27 a.m. GMT). Experts say it would not be visible without a powerful telescope.

The agency said the asteroid was discovered and reported Saturday by amateur astronomer Gennadiy Borisov, who operates an observatory in Nauchnyi, Crimea.

NASA says additional observations were reported to the Minor Planet Center, or MPC, - the internationally recognized authenticator of the position of small celestial bodies. The MPC operates from the Smithsonian Astrophysical Observatory at Harvard University in Cambridge, Massachusetts under the authority of the International Astronomical Union.

The data was automatically posted on the Near-Earth Object Confirmation Page website. Within three days, several observatories around the world had made dozens of observations, helping astronomers better refine 2023 BU's orbit.

The Center for Near Earth Object Studies, or CNEOS, at NASA's Jet Propulsion Laboratory in southern California analyzed the data from the MPC's confirmation page and predicted the near miss. CNEOS calculates every known near-Earth asteroid orbit to provide assessments on potential impact hazards in support of NASA's Planetary Defense Coordination Office.

JPL navigation engineer Davide Farnocchia said the CNEOS Scout impact hazard assessment system ruled out any threat of impact by the asteroid. But he said, despite very few observations, it was able to predict that the asteroid would make "an extraordinarily close approach with Earth."

"In fact, this is one of the closest approaches by a known near-Earth object ever recorded."

Some information for this report was provided by the Associated Press