Asteroid 2024 YW8 passs the Earth.

Asteroid 2024 YW8 passed by the Earth at a distance of 28 323 km (0.074 times the average distance between the Earth and the Moon, or 0.0002% of the distance between the Earth and the Sun, but 27 915 km above the altitude at which the International Space Station orbits), with a relative velocity of about 8.83 km per second, slightly after 9.25 pm GMT on Monday 30 December 2024. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2024 YW8 has an estimated equivalent diameter of 1-2 m (i.e. it is estimated that a spherical object with the same volume would be 1-2 m in diameter), and an object of this size would be expected to explode in an airburst (an explosion caused by superheating from friction with the Earth's atmosphere, which is greater than that caused by simply falling, due to the orbital momentum of the asteroid) more than 42 km above the ground, with only fragmentary material reaching the Earth's surface.

30 second image of 2024 YW8 taken with the Elena Planetwave 17" Telescope at Ceccano in Italy on 30 December 2024. The asteroid is the small point at the centre of the image, indicated by the white arrow, the longer lines are stars, their elongation being caused by the telescope tracking the asteroid over the length of the exposure. At the time when the image was taken, the asteroid was about 2.5 million km from the Earth. Gianluca Masi/Virtual Telescope Project.

2024 YW8 was discovered on 30 December 2024 (a few hours before its closest approach to the Earth) by the University of Arizona's Mt. Lemmon Survey at the Steward Observatory on Mount Lemmon in the Catalina Mountains north of Tucson. The designation 2024 YW8 implies that the asteroid was the 222nd object (asteroid W8 - in numbering asteroids the letters A-Z, excluding I, are assigned numbers from 1 to 25, with a number added to the end each time the alphabet is ended, so that A = 1, A1 = 26, A2 = 51, etc., which means that W8 = (8 x 25) + 22 = 222) discovered in the second half of December 2024 (period 2024 y - the year being split into 24 half-months represented by the letters A-Y, with I being excluded).

The relative positions of 2024 YW8 and the Earth at 9.00 pm on Monday 30 December 2024. JPL Small Body Database.

2024 YW8 is calculated to have a 594 day (1.60 year) orbital period, with an elliptical orbit tilted at an angle of 2.19° to the plain of the Solar System which takes in to 0.91 AU from the Sun (91% of the average distance at which the Earth orbits the Sun) and out to 1.82 AU (1.82 times the distance at which the Earth orbits the Sun, more than the distance at which the planet Mars orbits). 

The positions and orbits of 2024 YW8 and the planets of the Inner Solar System at 9.00 pm on Thursday 30 December 2024. JPL Small Body Database.

2024 VW8 is therefore classed as an Apollo Group Asteroid, which is an asteroid that is on average further from the Sun than the Earth, but which does get closer. 2024 VW8 is calculated to have fairly regular close encounters with the Earth, with the last thought to have happened in January 2017 and the next predicted for December 2028. The asteroid is also predicted to have occasional close encounters with the planet Mars, with the next predicted for April 2069.

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