Asteroid 2024 RL8 passes the Earth.

Asteroid 2024 RL8 passed by the Earth at a distance of about 329 350 km (1.12 times the average distance between the Earth and the Moon, or 0.29% of the distance between the Earth and the Sun), with a relative velocity of about 13.33 km per second, slightly before 10.40 pm GMT on Wednesday 11 September 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 RL8 has an estimated equivalent diameter of 6-19 m (i.e. it is estimated that a spherical object with the same volume would be 6-19 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) between 40 and 22 km above the ground, with only fragmentary material reaching the Earth's surface.

300 second image of 2024 RL8 taken with the Elena Planetwave 17" Telescope at Ceccano in Italy on 9 September 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 RL8 was first detected on 7 September 2024 (four days before its closest approach to the Earth), by the University of Hawaii's PANSTARRS2 telescope. The designation 2025 RL8 implies that it was the 211th asteroid (asteroid L8 - 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 = 25, A2 = 49, etc., which means that L8 = (25 x 8) + 11 = 211) discovered in the first half of September 2024 (period 2024 R; the year being split into 24 half-months represented by the letters A-Y, with I being excluded).

The relative positions of 2024 RL8 and the Earth on at 11.00 pm on Wednesday 11 September 2024. JPL Small Body Database.

2024 RL8 is calculated to have a 480 day (1.31 year) orbital period, with an elliptical orbit tilted at an angle of 12.01° to the plain of the Solar System which takes in to 0.71 AU from the Sun (71% of the average distance at which the Earth orbits the Sun, and slightly inside the orbit of Venus) and out to 1.69 AU (1.69 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 RL8 and the planets of the Inner Solar System at 11.00 pm on Wednesday 11 September 2024. JPL Small Body Database.

2024 RL8 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 RL8 is calculated to have fairly regular close encounters with the Earth, with the last thought to have happened in September 2020 and the next predicted for August 2028. The asteroid is also predicted to have regular close encounters with the planet Venus, with the last thought to have happened in June 2019 and the next predicted for June 2027.

See also...