International Asteroid Day: Asteroids Pass by Earth in a Fortuitous Celebration

This week, two asteroids passed by Earth, coinciding perfectly with International Asteroid Day. According to global space agencies, neither of these asteroids posed any danger to our planet.

One of the asteroids, named 2024 MK, was discovered earlier in June. It came within 300,000 kilometers of Earth, which is about 77% of the distance between Earth and the Moon. Astrophysicist Gianluca Masi, who runs The Virtual Telescope Project, explained that this asteroid, measuring around 200 meters in diameter, was closest to Earth about 10 hours before a live YouTube feed at 2:30 am IST on June 30.

Mr. Masi described the asteroid as “huge” and “significantly close” but reassured that it posed no risk. He noted that the asteroid was very bright during its close approach, making it visible with modest binoculars in certain parts of the world, like the Southwestern Americas. He called the event “exceptional.”

The asteroid was moving at an average speed of nine meters per second, which Mr. Masi found “peculiar” because it was quite fast against the backdrop of stars.

International Asteroid Day, celebrated on June 30, marks the anniversary of the largest recorded asteroid impact in 1908, which flattened over 80 million trees in Tunguska, Siberia. Asteroids, often referred to as ‘minor planets,’ are remnants from the formation of the Solar System. There are about a billion of these rocky objects orbiting the Sun.

The European Space Agency (ESA) emphasized the importance of improving our ability to detect potentially hazardous objects like 2024 MK, which was discovered on June 16, 2024.

The second asteroid, named (415029) 2011 UL21, is much larger, measuring 2.3 kilometers across. According to the ESA, it is bigger than 99% of all known near-Earth objects (NEOs). This asteroid came within 6.6 million kilometers of Earth, which is 177 times the distance to the Moon. Mr. Masi described this as a “truly safe encounter.”

This asteroid is among the top 10 largest to come within 7.5 million kilometers of Earth since 1900. The ESA estimates there are about 5 million NEOs larger than 20 meters, the size above which an impact could cause damage on the ground.

As part of its planetary defense efforts, the ESA plans to launch the Hera mission in October 2024. Hera will conduct a detailed survey of the asteroid Dimorphos, which was targeted by NASA’s Double Asteroid Redirection Test (DART) mission on September 26, 2022. DART was the first mission to demonstrate deflecting an asteroid by striking it to change its motion in space.

DART successfully hit Dimorphos, a moonlet about 160 meters in diameter, which orbits a larger asteroid called Didymos. Chrisphin Karthick, a scientist at the Indian Institute of Astrophysics in Bengaluru, who was involved in the DART mission, said this was a significant step towards preparing for potential future asteroid impacts, similar to the one that led to the extinction of dinosaurs 66 million years ago.

Mr. Karthick emphasized the importance of preparing our defenses against potentially hazardous asteroids and comets that orbit the Sun. He noted that while very few pose a threat to Earth, it is wise to be prepared for those that might be on a collision course in the future.

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)