Interstellar comet 3I/ATLAS nears the Sun on 29 October-Here’s why it matters

Interstellar Comet 3I/ATLAS (Image: NASA)

On 29 October, a rare interstellar visitor traverses our inner Solar System. It will reach its closest point to the Sun. This event will offer scientists a unique chance to probe material from beyond our stellar neighbourhood.

Interstellar visitor to reach Sun-hugging milestone

The interstellar comet 3I/ATLAS will reach its closest point to the Sun, on 29 October 2025. This will prompt astronomers to focus intense observation efforts. This milestone is particularly noteworthy. The comet’s unusual trajectory and composition already mark it as a rare visitor from beyond our Solar System.

Why the date matters?

At perihelion, the comet will be about 1.36 astronomical units (AU) from the Sun. It is roughly the same as Mars's orbit. This means that solar heating will be maximal, potentially triggering enhanced outgassing and revealing volatile materials that might shed light on its origin.

What scientists hope to learn?

Researchers expect that during this close solar passage the object’s unusual features, such as interstellar origin, retrograde trajectory and exotic chemistry. If outgassing intensifies, telescopes and space-based observatories will have the best chance to analyse the composition of the coma and tail. This study will offer insights into material from another star system.

Observational challenges ahead

The comet will be nearly behind the Sun from Earth’s vantage point on October 29. According to NASA, although 3I/ATLAS's trajectory brings it into the inner solar system, it will not come close to Earth. Nonetheless, space-based assets and observatories at favourable angles may still capture critical data during the perihelion passage.