Context: 

Earth is about to gain a temporary Mini-Moon as an asteroid named ‘2024 PT5’ will pass by Earth and will be visible through telescopes along with the moon.                

More on the news:

• A recent study reveals that Earth's gravitational field will temporarily capture a small asteroid named 2024 PT5 in late September. 
• Scientists discovered 2024 PT5 and shared their findings in the journal Research Notes of the American Astronomical Society earlier this month.

What are Mini Moons?

• Mini-moons are asteroids that get caught by Earth’s gravity and resulting in them temporarily orbiting the planet.
• Mini-moons are typically very small and difficult to detect. 

Characteristics:

• The length of time these mini-moons remain in orbit depends on the speed and trajectory with which they approach the Earth.
• Mini-moons do not have stable orbits and can stay in Earth's orbit for a few months to up to two years before breaking free from the Earth's gravitational pull and returning to space on a trajectory away from Earth.
• They follow a “horseshoe” orbit path as a result of the asteroids being constantly pulled forwards and backwards by the gravity of Earth.
• Mini-moons can be composed of a mixture of metallic substances, carbon, clay, and silicate material.

Origins: 

• According to a 2018 mini-moons study published in the Swiss journal, Frontiers in Astronomy and Space Sciences, most mini-moons come towards Earth from the asteroid belt between Mars and Jupiter.

Examples:

• An asteroid named 2020 CD3, which served as a mini-moon was temporarily bound to Earth for several years before it left the planet's orbit in 2020. 
• Another asteroid, 2022 NX1, also served as a mini-moon of Earth from 1981 to 2022 and is expected to return in 2051.

About Asteroid 2024PT5:

• It was first spotted in August by the NASA-funded Asteroid Terrestrial-impact Last Alert System (ATLAS) located at the Haleakala Observatory on the island of Maui, Hawaii.

Characteristics:

• The asteroid 2024 PT5 is not a mini-moon technically, as it will not complete one full revolution around Earth but will remain in the planet’s orbit for over 56 days.  
• This asteroid is roughly 10 meters (33 feet) in diameter and will be captured by Earth's gravity from September 29 to November 25, 2024.
• Earth has gained "mini-moons" before but this event is uncommon because earlier asteroids either missed the planet or disintegrated upon entering the Earth’s atmosphere.

Significance: 

• Mini-moons are considered important in the science community, as they contain precious metals.
• According to scientists, this asteroid is possibly a piece of ejecta from an impact on the moon.
• 2024 PT5 is larger than some of the other mini-moons, and will also return to Earth's orbit — in 2055.