Earth to get a mini-moon for two months, but what is it?

From precocious September until precocious November this year, a “mini-moon”, called 2024 PT5 by the astrologers who spotted it approaching volition beryllium orbiting the planet. Although this mini-moon cannot beryllium seen by the bare oculus – it is conscionable 10 metres (33ft) successful diameter – it tin beryllium viewed done a high-powered telescope.

Mini-moons are asteroids which person been pulled by the Earth’s gravity into orbit astir the satellite and stay determination until they go dislodged and determination distant again. The magnitude of clip these mini-moons stay successful orbit depends connected the velocity and trajectory with which they attack the Earth.

Most mini-moons that participate Earth’s orbit are hard to spot due to the fact that they are excessively tiny and not agleam capable to beryllium seen against the backdrop of the acheronian of space.

What, exactly, is simply a mini-moon?

Mini-moons are highly rare. Asteroids are usually pulled into Earth’s orbit by the gravity of the satellite arsenic seldom arsenic erstwhile successful 10 to 20 years, but a fewer much person appeared successful caller years. They tin stay successful the exosphere, which is astir 10,000km (6,200 miles) supra the aboveground of the Earth.

On average, mini-moons stay successful Earth’s orbit for thing from a fewer months to 2 years with the asteroid yet breaking distant from Earth’s gravitational pull, past moving backmost into abstraction to resume a trajectory distant from the planet.

Similar to different rocky bodies successful space, mini-moons tin beryllium composed of a substance of metallic substances, carbon, clay and silicate material.

According to a 2018 mini-moons survey published successful the Swiss journal, Frontiers successful Astronomy and Space Sciences, astir mini-moons travel towards Earth from the asteroid loop betwixt Mars and Jupiter.

Unlike Earth’s imperishable moon, mini-moons bash not person unchangeable orbits. Instead, they embark connected a “horseshoe” orbit way arsenic a effect of the asteroids being perpetually pulled forwards and backwards by the gravity of Earth.

This orbital instability allows the asteroids to gradually determination farther distant from Earth’s gravitational pull. Once the mini-moon has escaped Earth’s gravitational pull, it is released backmost into space.

Although mini-moons are usually rare, respective person been identified wrong Earth’s orbit since 2006.

In that year, 2006 RH120, the Earth’s archetypal confirmed mini-moon with a diameter of astir 2 to 4 metres was captured successful Earth’s orbit for astir a year. This was the lone mini-moon to person been photographed. The Southern African Large Telescope (SALT) was utilized to seizure the representation of it. It was spotted by the Catalina Sky Survey (CSS) which was established by NASA utilizing telescopes adjacent Tucson, Arizona successful 1998 to hunt for “near-Earth objects”.

Visitors presumption the 91 hexagonal reflector segments that marque up the array of the Southern African Large Telescope (SALT) adjacent Sutherland successful South Africa’s arid Karoo portion connected November 10, 2005, conscionable months earlier it captured the archetypal representation of a mini-moon successful 2006 [Mike Hutchings/Reuters]

The 2022 NX1 mini-moon, with a diameter of determination betwixt 5 and 15 metres was archetypal seen successful 1981, past again successful 2022.

It is expected to instrumentality to Earth’s orbit to instrumentality up a horseshoe orbital way again successful 2051.

What bash we cognize astir the latest mini-moon?

The asteroid presently approaching the satellite is known arsenic 2024 PT5. It was archetypal spotted connected August 7 utilizing the NASA-funded Asteroid Terrestrial-impact Last Alert System (ATLAS) located astatine the Haleakala Observatory connected the land of Maui, Hawaii.

The strategy continuously scans the entity portion identifying and tracking near-Earth objects that mightiness either airs a menace to the Earth oregon supply an accidental to stitchery important technological knowledge.

“Every clip an entity with an orbit truthful Earthlike is discovered, determination is simply a accidental that we are conscionable recovering abstraction debris,” said Raul de la Fuente Marcos, an astronomer astatine the Complutense University of Madrid and a co-author of the study.

However, astronomers from the survey person present confirmed that 2024 PT5 is an asteroid.

Astronomers person determined that the mini-moon volition implicit a trajectory astir the Earth from September 29 to November 25, earlier yet breaking escaped from Earth’s gravitational propulsion earlier heading into space.

Are determination different types of moon?

Apart from our imperishable moon, which tin look successful antithetic forms depending connected conditions, determination are immoderate different types of “moon”.

Ghost moons

Also known arsenic Kordylewski clouds, shade moons are concentrations of particulate that are typically recovered successful the Lagrangian points successful the Earth-moon system.

These Lagrangian points, sometimes known arsenic gravitational “sweet spots”, are wherever the gravitational forces of the Earth and the satellite meet, allowing the shade satellite to support a unchangeable position.

These clouds tin measurement arsenic overmuch arsenic 100,000km crossed and were archetypal discovered by Polish astronomer Kazimierz Kordylewski successful the 1960s utilizing a method called polarimetry, measuring the absorption of however airy waves vibrate. These particulate clouds were aboriginal confirmed successful 2018 by the Royal Astronomical Society.

(Al Jazeera)

Quasi-moons

These moons stock an orbit with Earth astir the Sun but bash not orbit the Earth themselves. Instead, a quasi-moon follows a way astir the Sun that intimately matches Earth’s orbit, but is not an nonstop match.

In 2016, HO3, a quasi-moon, was discovered by astronomers utilizing the Pan-STARRS 1 scope successful Hawaii. Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) is simply a task designed to observe near-Earth objects specified arsenic asteroids oregon comets, which travel from further afield than the asteroid loop betwixt Mars and Jupiter.

2016 HO3 is betwixt 100 and 300 metres successful diameter and, according to scientists, volition proceed to orbit the Sun for hundreds of years. It is not known however agelong it has already been orbiting the Sun.

Other celestial bodies, specified arsenic planets, moons and asteroids, tin besides beryllium orbited by quasi-moons. Venus, Jupiter, Saturn, Neptune and Pluto each person quasi-moons which volition yet alteration their paths and permission orbit.

Even the asteroid Ceres, presently located successful the constellation of Sagittarius and classified arsenic a dwarf satellite with a diameter of astir 940km (about 584 miles), has its ain quasi-moon.

The dwarf planet, Ceres, is seen successful the main asteroid loop betwixt the orbits of Mars and Jupiter, arsenic illustrated successful this artist’s conception released by NASA connected January 22, 2014 [NASA/ESA/Handout via Reuters]

The archetypal quasi-moon ever detected, Zoozve, was discovered connected November 11, 2002, by astronomer Brian A Skiff astatine the Lowell Observatory successful Arizona. The asteroid has a calculated diameter of astir 236 metres (about 775 feet).

Fortunately, determination person been nary known quasi-moons that person escaped their orbital way and travel adjacent to hitting the Earth.

Are we capable to survey these asteroids?

Yes. China’s Tianwen-2 ngo is simply a abstraction exploration task acceptable to motorboat successful 2025. The ngo aims to cod samples from the quasi-moon asteroid 469219 Kamoʻoalewa, which is astir 40 to 100 metres successful length. Asteroid 469219 Kamoʻoalewa was discovered connected April 27, 2016, by the Pan-STARRS 1 asteroid survey scope astatine Haleakala Observatory successful Hawaii.

However, the Tianwen-2 ngo is not the lone task to cod samples from an asteroid. The archetypal ngo to successfully cod samples from an asteroid was the Hayabusa Mission, launched connected May 9, 2003 by the Japan Aerospace Exploration Agency (JAXA).

The Itokawa asteroid is seen astir 300 cardinal kilometres(186 cardinal miles) from Earth successful this handout representation taken connected November 20, 2005, by the Japanese unmanned Hayabusa and released by the Japan Aerospace Exploration Agency (JAXA) [Japan Aerospace Exploration Agency/Handout/Reuters]

The spacecraft landed connected the 535-metre asteroid 25143 Itokawa connected September 12, 2005 and successfully collected samples connected November 19, 2005 and November 25, 2005, past returned to Earth connected June 13, 2010.

Several different asteroid postulation missions person besides launched from Japan. The Hayabusa 2 Mission launched connected December 3, 2014 to cod samples from the 900-metre 162173 Ryugu asteroid. Samples were successfully collected connected February 21 and July 11, 2019. The spacecraft returned to Earth connected December 6, 2020.

A betterment squad subordinate examines a capsule containing NASA’s archetypal asteroid samples earlier it is taken to a impermanent cleanable country astatine Dugway Proving Ground successful Utah connected Sunday, September 24, 2023 [Rick Bowmer/AP]

The OSIRIS-REx Mission was launched by NASA connected September 8, 2016 to cod samples from the near-Earth asteroid, 101955 Bennu (492 metres). OSIRIS-REx arrived astatine Bennu connected December 3, 2018, and collected samples connected October 20, 2020. The samples returned to Earth connected September 24, 2023.

NASA has announced that OSIRIS-APEX, a follow-on ngo from OSIRIS-REx, volition survey the asteroid Apophis, erstwhile it comes wrong a adjacent region to the Earth successful 2029.