As of December 17, 2024, NASA has identified over 1.1 million asteroids, with thousands more discovered monthly. Among these, particular attention is given to near-Earth asteroids (NEAs), which approach Earth's orbit and may pose potential hazards.
On this day, twenty asteroids will reach their closest point to Earth, including one classified as potentially hazardous.
The largest NEA approaching Earth today is (2012 PA), estimated to have a diameter between 228 and 511 meters, making its closest approach at 19:37 UTC. The second largest is (2015 YN10), with a diameter of 211 to 472 meters, while (2015 DC200) ranks third in size.
The asteroid (2022 YO1) will come closest to our planet, at a distance of 0.8 million kilometers, around 15:40 UTC.
The closest recorded approach to Earth without a collision occurred on August 16, 2020, when (2020 QG) passed just 3,000 kilometers away at a speed of approximately 44,000 km/h. It was detected only six hours after its flyby.
Potentially hazardous asteroids are defined as those that come within 0.05 astronomical units (about 7.5 million kilometers) of Earth's orbit and have an absolute magnitude of 22 or less, indicating a size of at least 140 meters in diameter. Approximately 20 percent of NEAs are categorized as potentially hazardous.
Today, one potentially hazardous asteroid, (2015 DC200), is near Earth. Its first observation was on February 24, 2015, with the last recorded observation on December 25, 2017. It has an absolute magnitude of 20.5, a diameter ranging from 211 to 472 meters, and will be at a distance of 22.5 million kilometers, traveling at a speed of 130,806.55 km/h at its closest approach at 07:59 UTC.
Near-Earth asteroids that cross Earth's orbit are referred to as Earth-crossers. Apollo-type NEAs cross Earth's orbit from the outside, while Aten-type NEAs approach from the inside. Today, a total of seventeen Earth-crossers are nearing our planet.
Asteroids of the Amor and Atira types do not cross Earth's orbit, with Atira asteroids remaining entirely within Earth's orbit.