Earth gets second moon for a short time

The Earth will briefly gain a second companion: an asteroid will orbit our planet for almost two months, but it will not be visible to the naked eye.

While some planets have numerous moons, such as Saturn with its 145 satellites, Earth has only one moon—at least for now. Soon, our planet will have a mini-moon for a limited time.

This mini-moon is an asteroid named 2024 PT5. The small rock will approach Earth at the end of September and will orbit our planet for a period of time due to gravitational attraction—specifically, for 57 days from September 29 to November 25.

In contrast to our “permanent” moon, which has a diameter of 3,475 kilometers, the asteroid has a diameter of only ten meters, making it very small. This is why it cannot be seen without assistance—neither with the naked eye nor with regular binoculars or a telescope.

Researchers from the Universidad Complutense de Madrid have determined that 2024 PT5 likely belongs to the Arjuna asteroids, which are near-Earth asteroids. These asteroids are characterized by an Earth-like orbit around the sun and an orbital period of approximately one Earth year.

Due to its similar orbit, 2024 PT5 is expected to be a temporary companion to Earth more frequently—in 2025 and 2055, according to current calculations.

While it is uncommon for asteroids to act as a “moon” of our planet for a limited time, it is not an unprecedented event. The asteroid NX1 last orbited Earth in 2022, and before that, it did so in 1981. NX1 may also return in 2051. However, similar to 2024 PT5, with a diameter of ten meters, NX1 will also be invisible to us.

The Earth Will Have a Second Companion: Asteroid 2024 PT5

Introduction to Asteroid 2024 PT5

Our planet, Earth, is set to welcome a brief visitor: an asteroid named 2024 PT5. This miniature celestial body will orbit our planet for a significant period, specifically for 57 days, from September 29 to November 25. Unlike the familiar sight of our moon, which has a diameter of approximately 3,475 kilometers, 2024 PT5 is a mere ten meters across, making it virtually invisible to the naked eye, as well as through common binoculars or telescopes.

What Is a Mini-Moon?

A mini-moon refers to a small asteroid that temporarily orbits the Earth, often for a limited time. These asteroid-like companions can be intriguing phenomena. Asteroids like 2024 PT5 serve as a reminder of the dynamic nature of our solar system and the various celestial bodies that can be present around Earth.

Characteristics of Asteroid 2024 PT5

Typically, asteroids in this category exhibit several defining characteristics:

• They possess Earth-like orbits around the sun.
• Their orbital period is approximately one Earth year.
• They can vary significantly in size, but many, like 2024 PT5, are on the smaller scale.

The Journey of Asteroid 2024 PT5

Asteroid 2024 PT5 is likely a member of the Arjuna asteroids group, characterized by their proximity to Earth. These asteroids often come close to our planet, creating a logical pattern of orbit and approach. Scientists from the Universidad Complutense de Madrid have noted its trajectory and predict that this won’t be the last visit. Future encounters are projected for 2025 and 2055.

History of Earth’s Mini-Moons

This occurrence, while rare, is not unprecedented. For instance, the asteroid NX1 orbited the Earth during previous years, specifically in 2022 and 1981, with a potential return anticipated in 2051. Just like 2024 PT5, NX1 had a smaller diameter, making it invisible to the naked eye.

Why Are Mini-Moons Important to Science?

Studying mini-moons like 2024 PT5 can offer valuable insights into the following areas:

Meteorite Composition

Through closer observation of mini-moons, scientists can learn about the composition and structure of these celestial objects, which may share similarities with larger asteroids.

Orbital Dynamics

Understanding the gravitational dynamics between Earth and these mini-moons can also aid our comprehension of space physics and celestial mechanics.

Risk Assessment

Frequent studies of near-Earth asteroids contribute to the development of impact risk assessments, which can be crucial for future planetary defense strategies.

Practical Tips for Asteroid Enthusiasts

If you’re keen on staying updated about future mini-moons and other celestial events, here are some practical tips:

• Follow Space Agencies: Keep an eye on announcements from organizations such as NASA and ESA for upcoming asteroid events.
• Join Astronomy Clubs: Engaging with local astronomy groups can provide insights into celestial phenomena, along with viewing opportunities through telescopes.
• Use Astronomy Apps: There are various apps available that help you track asteroids and give alerts about their approaches.

Potential Future Encounters: Mini-Moons Ahead

The potential for future encounters with mini-moons like 2024 PT5 is promising. Beyond 2025 and 2055, ongoing advancements in space observation technology may reveal even more near-Earth asteroids and their interactions with our planet.

Table of Notable Mini-Moons

Asteroid Name	Last Orbit Date	Size (meters)	Next Expected Orbit
2024 PT5	November 25, 2023	10	2025, 2055
NX1	2022	10	2051

The Future of Asteroid Research

As technology and methodologies in astronomical research evolve, the study of mini-moons will likely expand, enabling more frequent observations and potentially altering our understanding of the cosmos. This research garners curiosity and serves a crucial purpose in planetary protection.