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Earth to Gain a Temporary ‘Mini-Moon’
Context:
- A recent study has revealed that a small asteroid named 2024 PT5 will temporarily enter Earth’s gravitational field in late September.
- This phenomenon, often referred to as a “mini-moon,” occurs when an asteroid gets caught in Earth’s gravitational field and orbits the planet for a short period (2 months) before continuing its journey through space.
What Are Mini-Moons?
- Mini-moons are small asteroids that become temporarily captured by Earth’s gravity, orbiting the planet for a limited time.
- So far, only four mini-moons have been identified, and none remain in orbit today.
- Some objects mistaken for mini-moons, like the Gaia spacecraft and rocket stages from lunar missions, highlight the challenges in detecting these small bodies.
Key Highlights:
- Mini-moon events are categorised as either long captures (lasting a year or more) or short captures (lasting days, weeks, or months).
- Short captures like PT5’s occur several times per decade, while long captures are much rarer, happening every 10-20 years.
- The asteroid 2024 PT5 was discovered on August 7, 2024, using the NASA-funded Asteroid Terrestrial-impact Last Alert System (ATLAS).
- This system, developed by the University of Hawaii, uses four telescopes located in Hawaii, Chile, and South Africa to detect potential asteroid impacts.
- 2024 PT5 is estimated to be just 33 feet long, making it too small to be visible to the naked eye or through typical amateur telescopes. However, it is within the brightness range of telescopes used by professional astronomers.
- The asteroid is believed to have originated from the Arjuna asteroid belt, a secondary asteroid belt composed of space rocks that follow orbits very similar to that of Earth.
- 2024 PT5 will perform a horseshoe-shaped orbit rather than completing a full revolution around Earth, leading some researchers to question its classification as a mini-moon.
Significance:
- Observations of 2024 PT5 will enhance understanding of near-Earth asteroids, including those that may collide with Earth.
- Asteroids are of interest due to their potential mineral and water resources, which could be valuable for future space missions.