3I/ATLAS' Closest Earth Approach: Catch the Rare Chance to See It! When and How to View the Comet

3I/ATLAS has become a great fascination for astronomers, scientists, and the public. This is because it is only the third confirmed interstellar object to ever come across our solar system. It follows in the footsteps of other interstellar visitors - the 1I/'Oumuamua and the visibly active 2I/Borisov. These comets give a rare glimpse into the composition of a distant stellar system.

In a landmark event for the scientific community and common stargazers alike, the interstellar comet 3I/ATLAS is set to make its historic closest approach to Earth this Friday, 19 December 2025. This celestial encounter is a once-in-a-lifetime opportunity for observers because, based on its hyperbolic trajectory, it is on a terminal path through our solar system which means, the upcoming flyby will be its final appearance before it moves into the deep reaches of the cosmos, never to return.

Discovery of the Third Interstellar Object and Origins

The NASA-funded Asteroid Terrestrial-impact Last Alert System (ATLAS) survey telescope in Rio Hurtado, Chile, discovered 3I/ATLAS on 1 July 2025. Scientists and astronomers quickly identified the object as interstellar because of its highly hyperbolic trajectory and an eccentricity of approximately 6.1.

It is said to be travelling at an astonishing speed of 60 kilometres per second. It is believed to have originated from the Milky Way's 'thick disk,' a region of space containing stars that formed nine to 13 billion years ago. For this reason, 3I/ATLAS is also being referred to as a 'cosmic relic' and is presumed to possibly be carrying material from a time period known as the 'cosmic noon'—the peak of star formation and galaxy growth in our galaxy's early history.

Why the Arrival of 3I/ATLAS Matters Today

The arrival of the interstellar object 3I/ATLAS represents far more than a fleeting astronomical spectacle - it serves as a 'free' scientific mission delivered directly to our cosmic doorstep. By analysing the comet as it passes through our solar system, researchers can study its dust composition and mass-loss rate in real-time.

This is a significant advantage, as it eliminates the need to launch expensive robotic probes or deep-space spacecraft to gather data from distant star systems. Moreover, astronomers are using this rare close encounter to answer key questions about the universe.

By examining the materials trailing from 3I/ATLAS, researchers can determine if the building blocks of planets in other parts of the galaxy are identical to those that formed Earth. The data may also reveal if the chemical substances for life and planetary formation are a universal standard or if our solar system is unique.

When and How to View 3I/ATLAS on Its Flyby This Week

3I/ATLAS will reach its closest point to Earth this Friday, December 19. While it will not be visible to the naked eye, everyone can still see it through high-powered telescopes and observatories.

However, several groups are offering free livestream viewings for the public. Enthusiasts can visit the Virtual Telescope Project for a livestream hosted by astrophysicist Gianluca Masi. He will be using a high-tech robotic telescope in Italy to provide high-definition views of the interstellar object.

The broadcast schedule is as follows:

18 December: 23:00 EST (20:00 PST)

19 December: 04:00 UTC (12:00 PHT)

Where to Watch: The Virtual Telescope Project YouTube Channel