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Mini-moon discovery -

On August 7, 2024, NASA-funded scientists discovered an asteroid they named 2024 PT5 during routine monitoring using the Asteroid Terrestrial-impact Last Alert System in South Africa.

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When will the mini-moon orbit Earth? -

Asteroid 2024 PT5 began its orbit around Earth on September 29, and it will end on November 25, before returning to the Arjuna belt that revolves around the sun.

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When was the first known mini-moon event of 2024? -

The first mini-moon event of 2024 involved asteroid 2023 TFF, which was captured by the Earth's gravity and orbited the planet for several months at the start of the year.

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Where did the asteroid come from? -

Scientists said the asteroid came from the Arjuna asteroid belt, a group of asteroids 93 million miles away that is temporarily joining the moon in its orbit around the Earth.

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The Arjuna asteroid belt -

The Arjuna asteroid belt is a secondary asteroid belt made of space rocks that follow orbits very similar to that of Earth. Objects in the Arjuna asteroid belt can approach Earth at a close range of around 2.8 million miles (4.5 million kilometers).

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How big is the asteroid? -

Asteroid 2024 PT5 is around 33 feet (10 meters) long, which is about the same size as a bus. Experts believe it will make a horseshoe-shaped orbit around the Earth.

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How big is 2024 PT5 compared to the Earth and Moon? -

A length of 33 feet (10 meters) may seem substantial, but Earth is approximately 389,450 times larger, while the Moon is about 105,400 times larger than asteroid 2024 PT5 in diameter.

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How long will the mini-moon be in the Earth's orbit? -

The mini-moon will be in the Earth's orbit for around two months. It'll make its closest approach in January 2025, after which it's next expected to make a return to Earth's orbit in 2055.

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What is a mini-moon? -

When asteroids approach Earth, they either pass by the planet or hit it and leave debris in the atmosphere. Some, however, can get caught in Earth's gravity and become temporary mini-moons.

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What is a mini-moon? -

Mini-moons orbit the Earth for a short time, typically less than a year. To be considered a mini-moon, an asteroid or space body must approach Earth at a distance of around 2.8 million miles (4.5 million km) and travel at speeds of about 2,200 mph (3,540 km/h).

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Gravitational interactions -

The capture of a mini-moon typically occurs when the asteroid passes close enough to a planet that its gravity can temporarily pull it into orbit, which is influenced by the object's velocity and trajectory.

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Types of mini-moon events -

There are two types of mini-moon events. The first are long episodes during which the asteroid completes one or more revolutions around Earth, with these gravitational interactions lasting one or more years. 

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Types of mini-moon events -

The second type of mini-moon event is a short engagement in which the asteroid doesn't complete one full revolution. It can last days, weeks, or even a few months. 

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How many mini-moon events have taken place? -

So far, scientists have only identified two long episodes, 2006 RH120 and 2020 CD3. There are four published examples of short captures: 1991 VG, 2022 NX1, 2023 TFF, and 2024 PT5. 

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How often are mini-moon events? -

Experts say short mini-moon events involving an asteroid gaining negative geocentric energy for weeks or months occur fairly frequently, with several happening each decade. In contrast, long capture episodes are rare, occurring about once every ten to twenty years.

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Can you see the mini-moon? -

The mini-moon won't be visible to the naked eye due to its size. Experts also say the asteroid is too small and dim to be observed through amateur telescopes and binoculars.

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Could the asteroid be a piece of the Earth's Moon? -

According to scientists, the previous motion of asteroid 2024 PT5 suggests it could be a piece of ejecta from an impact on the Moon. 

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How are asteroids made? -

Asteroids are made from the leftover materials that didn't form into planets during the early solar system's formation about 4.6 billion years ago.

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The threat of an asteroid hitting Earth -

In recent years, NASA has been taking the threat of an asteroid coming into contact with Earth more seriously. In 2022, it carried out its first Double Asteroid Deflection Test, which changed an asteroid's orbit. 

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OSIRIS-REx spacecraft -

In 2016, NASA launched the OSIRIS-REx spacecraft on a mission to an asteroid near Earth called Bennu to collect a sample of rocks and dust from Bennu's surface. Experts believe the asteroid has a chance to collide with Earth in 2182.

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Should we be worried about the asteroid? -

Experts say there is no need to worry about the asteroid threatening Earth as it will be in the Moon's orbit, which is too far away to be a threat.

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What will happen to the 2024 PT5 asteroid? -

The 2024 PT5 asteroid will eventually escape the Earth's gravitational influence and continue on its trajectory through space. It will return to its original orbit in the Arjuna asteroid belt.

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Gaining a better understanding -

Astronomers are working to catalog these types of asteroids to better understand their locations, as any that come close enough to Earth could potentially pose an impact threat.

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How many times has the Earth been hit by an asteroid? -

Astrogeologists have determined that during the last 600 million years, the Earth has been struck by 60 objects of a diameter of 3 miles (5 kilometers) or more.

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Impact events -

In 1908, a 98-foot (30-meter) asteroid or comet entered the atmosphere and exploded above Tunguska, Russia. The impact destroyed 80 million trees over an area of 830 square miles (2,150 square kilometers).

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Chelyabinsk event -

In 2013, a 56-foot (17-meter) asteroid exploded over Chelyabinsk in Russia. Around 1,500 people were injured, mostly by flying glass when the explosion's shock wave hit the ground.

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When will the next impact event take place? -

The next serious asteroid predicted to pass close to the Earth is Apophis in 2029. It will come within about 20,000 miles (32,000 kilometers) of Earth's surface. However, thanks to precise tracking, experts have ruled out any chance of impact for at least the next 100 years.

Sources: (CNN) (Forbes) (ABC) (Space) (CBS News) (Britannica)

See also: Space tourism: would you try it?

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