Two large asteroids are set to pass by Earth this week, coinciding with this year's Asteroid Day celebrations.
While neither asteroid poses any risk to our planet, the close approach of one of them, discovered only a week ago, underscores the importance of improving our ability to detect potentially hazardous objects in our cosmic neighbourhood.
Asteroid 2024 MK, discovered on June 16, 2024, is between 120 and 260 meters in size. It will make its closest approach to Earth on June 29, during the height of Asteroid Day activities. This near-Earth object (NEO) will pass within 290,000 kilometres of Earth's surface, roughly 75% of the distance between Earth and the Moon.
Despite its proximity, there is no risk of 2024 MK impacting Earth. However, its discovery just a week before its flyby highlights the ongoing need to enhance our detection and monitoring capabilities for potentially hazardous NEOs.
Due to its size and proximity, 2024 MK will be observable in clear dark skies on June 29 using a small telescope or good binoculars. Amateur astronomers in some parts of the world can plan their observations using the European Space Agency's (ESA) NEO toolkit.
The second asteroid, (415029) 2011 UL21, is significantly larger, measuring 2,310 meters across. It will make its closest approach on June 27, but it will remain more than 17 times the distance between Earth and the Moon. This asteroid's steeply inclined orbit around the Sun is unusual for such a large object and may be the result of gravitational interactions with a large planet like Jupiter. Understanding these interactions is crucial, as Jupiter can deflect previously safe asteroids towards Earth.
Asteroid Day, endorsed by the United Nations, commemorates the largest observed asteroid strike in recorded history—the 1908 Tunguska event in Siberia, which felled around 80 million trees. This event serves as a reminder of the potential impact hazards posed by asteroids.
ESA has been at the forefront of planetary defense efforts, detecting and analyzing potentially hazardous NEOs. The agency's upcoming Hera mission, launching later this year, will perform a detailed post-impact survey of the asteroid Dimorphos following NASA's DART mission in 2022. This mission aims to develop a well-understood and repeatable planetary defense technique.
Additionally, ESA is developing a network of Flyeye telescopes to automatically scan the sky for new potentially hazardous asteroids and the NEOMIR satellite to spot
asteroids approaching from regions obscured by the Sun's glare.
These efforts highlight the importance of continued vigilance and innovation in protecting our planet from potential asteroid impacts.
