Two large asteroids pass Earth safely in just 42 hours

2024 MK – less than two weeks between discovery and flyby

Asteroid 2024 MK is between 120 and 260 magnitudes 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 the Earth’s surface – about 75% of the distance between the Earth and the Moon.

There is no risk of 2024 MK affecting Earth. However, an asteroid of this size would cause significant damage if it did, so its discovery just a week before it flew past our planet highlights the continuing need to improve our ability to detect and track potentially dangerous near-Earth objects (NEOs).

Because of its size and proximity, 2024 MK will be visible in the dark sky on June 29 with small telescopes for amateur astronomers in some parts of the world. Plan your observations using ESA’s NEO tool.

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

Asteroid (415029) 2011 UL21 is the largest of the week’s visitors. At 2310 meters wide, this asteroid is larger than 99% of all known near-Earth objects. However, it will not come anywhere near Earth. At its closest point on June 27, it will still be more than 17 times farther from the Moon.

This asteroid’s orbit around the Sun is very tilted, which is unusual for such a large object. Most large objects in the Solar System, including planets and asteroids, orbit the Sun in or near the equatorial plane.

This could be the result of a gravitational interaction with a giant planet like Jupiter. Jupiter can deflect previously safe asteroids towards Earth, so understanding this process is important.

(415029) 2011 UL21 is in ’11:34 resonance’ with Earth. It completes 11 revolutions about the Sun in almost the same amount of time as the Earth completes 34 revolutions (ie 34 years).

The result is an interesting repeating pattern when you see the location of the asteroid relative to Earth over a period of 34 years with the Earth aligned.

Asteroid Day 2024

The impact craters that scar the Earth’s surface are evidence of how asteroids have greatly influenced the history and development of our planet.

United Nations-sanctioned Asteroid Day commemorates the largest asteroid strike in recorded history – the 1908 space explosion over Tunguska in largely uninhabited Siberia, which felled nearly 80 million trees.

This represented a lucky escape for Europe: it happened only a short Earth orbit away from affecting the most populated continental areas.

ESA is in a unique position, with the cooperation and support of its Member States, to coordinate the data, information and expertise needed to understand and respond to outer space risks in Europe and to participate in wider human planetary protection efforts.

Over the past two decades, ESA has been conducting detection and analysis of potentially dangerous NEOs. There are an estimated 5 million NEOs out there larger than 20 m – the threshold above which an impact can cause damage below.

ESA increases asteroid activity

ESA’s Planetary Defense Office is implementing several projects aimed at improving our ability to detect, track and mitigate potentially dangerous asteroids.

Launching later this year, ESA’s Hera mission is part of the world’s first asteroid flyby experiment. 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 turn the experiment into a comprehensive and repeatable approach to planetary protection. Members of the Hera team will participate in Asteroid Day celebrations later this week.

Back on Earth, ESA is developing a network of insect-guided Flyeye telescopes that will use their unique wide field to automatically scan the sky each 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 cannot be seen from Earth because they are obscured by the glow of our star.

Meanwhile, the Office of Planetary Defense continues to watch space closely today. ESA’s fireball camera in Cáceres, Spain, captured a spectacular meteor on the night of 18-19 May 2024, which is thought to be a small fragment of a comet that flew over Spain and Portugal traveling at about 162 000 km/h before burning up. over the Atlantic Ocean.

Just a few weeks later, on June 6, 2024, the Catalina Space Observatory in Arizona, USA detected a small asteroid 2-4 meters in size that triggered an alert from ESA’s impact monitoring system (Meerkat). The alert was not for impact, but for a very close call. A few hours later, the object flew past the Catalina Sky Survey telescope which detected it at a distance of only 1750 km, making it the second closest pass by a known, non-impact asteroid ever.