A11PL3Z: The Interstellar Comet 3i/Atlas Traversing Our Solar System

Interstellar objects have been observed speeding through the solar system, prompting both amateur and professional astronomers globally to direct their telescopes toward them, refining their orbital models to confirm their status as visitors from other stars.

The comet was initially designated A11PL3Z and marks the third documented interstellar object. The first, ‘Oumuamua, was identified in October 2017, shortly after its closest approach to Earth. Its bizarre acceleration sparked numerous theories, including the possibility that it might be an alien spacecraft. The second interstellar object, Comet Borisov, was discovered in 2019, allowing for more extensive observations early in its journey through the solar system.

The A11PL3Z was first detected by NASA’s Asteroid Terrestrial Impact Last Alert System (ATLAS). Earlier images of the object, once overlooked, were identified in data collected on June 14. New observations are underway in Chile and beyond through the Deep Random Survey. The Minor Planet Center—charged with the observation and reporting of such entities—has now officially named it 3I/ATLAS, acknowledging both its classification as the third interstellar object and the discoverers.

The object measures approximately 20 km wide and is estimated to move at around 60 km per second, gradually accelerating due to the sun’s gravitational pull. By October, it will reach its closest point to the Sun, passing within two astronomical units (twice the distance from Earth to the Sun) before swinging away and exiting our solar system.

This creates a limited window for studying 3i/Atlas, although its visibility offers more time for observation compared to other interstellar entities. “They move through the solar system at astonishing speeds,” states Mark Norris from the University of Central Lancashire, UK. “It’s a race against time to learn as much as we can about them.”

Unfortunately, the technology needed to launch missions to intercept and investigate these celestial visitors remains out of reach, according to Norris. “Even if we started today, it would be too late,” he concludes. However, this may evolve soon, as the European Space Agency (ESA) aims to deploy a comet interceptor mission into space in 2029, where it will await encounters with newly discovered comets and interstellar bodies.

For now, astronomers must depend on existing telescopes to observe 3i/Atlas from a distance. “As we can track it until the end of the year, we have sufficient time to refine its trajectory, and there’s still time to focus the spectrometer on it,” mentions Richard Moisle. Our team is already eager to pinpoint the earliest possible observations. Everyone is highly enthusiastic and ready for what’s ahead.”

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