Two large asteroids safely pass by Earth just 42 hours apart

2024 MK – less than two weeks from discovery to flyby

Asteroid 2024 MK is between 120 and 260 meters in size and was discovered on June 16, 2024. The asteroid will fly by Earth on June 29, during the peak of this year’s Asteroid Day activities.

2024 MK is large for a Near Earth object (NEO) and will pass within 290,000 km of Earth’s surface – about 75% of the distance between Earth and the Moon.

There is no risk that MK 2024 will impact Earth. However, an asteroid of this size would cause significant damage if it did, so its discovery, just a week before it passes by our planet, underlines the continued need to improve our ability to detect and release potentially dangerous Near Earth Objects (NEOs). to monitor and improve.

Due to its size and proximity, 2024 MK will be visible in a clear, dark sky on June 29 using a small telescope or good binoculars for amateur astronomers in some parts of the world. Plan your observations using ESA’s NEO toolkit.

(415029) 2011 UL21 – larger than 99% of near-Earth asteroids

Asteroid (415029) 2011 UL21 is the biggest of the week’s visitors. With a diameter of 2310 meters, this asteroid is larger than 99% of all known Near Earth Objects (NEOs). However, it won’t come nearly as close to Earth. At its closest point on June 27, it will be more than seventeen times as far away as the moon.

This asteroid’s orbit around the Sun has a steep inclination, which is unusual for such a large object. Most large objects in the solar system, including planets and asteroids, orbit the sun at or near the equatorial plane.

This could be the result of gravitational interactions with a large planet like Jupiter. Jupiter can deflect previously safe asteroids towards Earth, so it is important to understand this process.

(415029) 2011 UL21 is in an ’11:34 resonance’ with Earth. It completes 11 revolutions around the sun in almost exactly the same time that the Earth completes 34 revolutions (i.e. 34 years).

The result is a pleasing repeating pattern when you visualize the asteroid’s location relative to Earth over a period of 34 years, while Earth is held in place.

Asteroid Day 2024

The impact craters that cover the Earth’s surface are a testament to how asteroids have greatly influenced the history and development of our planet.

The UN-sanctioned Asteroid Day commemorates the largest recorded asteroid impact in history: the 1908 explosion over Tunguska in largely desolate Siberia, which felled some 80 million trees.

This represented a lucky escape for Europe: it happened just a short Earth rotation away from affecting the more densely populated regions of the continent.

ESA is uniquely positioned, with the cooperation and support of its Member States, to coordinate the data, information and expertise needed to understand and respond to asteroid hazards in Europe and to participate in the wider humanity’s planetary defense efforts.

For the past twenty years, ESA has been conducting detection and analysis of potentially dangerous NEOs. There are an estimated 5 million NEOs larger than 20 meters – the threshold above which an impact can cause damage to the ground.

ESA is increasing its asteroid activities

ESA’s Planetary Defense Office is carrying out a number of projects aimed at improving our ability to detect, track and contain potentially dangerous asteroids.

ESA’s Hera mission, launching later this year, is part of the world’s first test of asteroid deflection. Hera will conduct a detailed post-impact study of the asteroid Dimorphos following the impact of NASA’s DART mission in September 2022 and help convert the experiment into a well-understood and repeatable planetary defense technique. Members of the Hera team will take part in the Asteroid Day celebration later this week.

Back on Earth, ESA is developing a network of insect-inspired Flyeye telescopes that will use their unique wide field of view to automatically scan the entire sky every night in search of new potentially dangerous asteroids.

Our future NEOMIR satellite will be located between the Earth and the Sun. It will use infrared light to spot asteroids approaching our planet from parts of the sky that are not visible from the ground because they are obscured by the glare of our star.

Meanwhile, the Planetary Defense Office continues to closely monitor the skies today. ESA’s fireball camera in Cáceres, Spain, captured a stunning meteor on the night of May 18-19, 2024. It is thought that this was a small piece of a comet that flew over Spain and Portugal at a speed of about 162,000 km/h before burning up. above the Atlantic Ocean.

Just a few weeks later, on June 6, 2024, the Catalina Sky Survey in Arizona, USA, discovered a small asteroid of 2 to 4 meters in size that triggered an alert from ESA’s impending impact monitoring system (Meerkat). That warning was not for an impact, but for a very close call. A few hours later, the object flew over the Catalina Sky Survey telescope which discovered it at a distance of just 1,750 km, making it the second-closest pass of a known non-impact asteroid ever.