Interstellar comet 3I/ATLAS will reach its closest point to Earth on Friday, 19 December, offering astronomers a narrow but important window to study a rare object passing through the solar system.
What is interstellar comet 3I/ATLAS?
The comet was first detected on 1 July by the NASA-funded ATLAS survey telescopes in Chile. Follow-up observations confirmed that it did not originate within the solar system. Its path indicates that it originated from interstellar space and will eventually depart again, continuing its long journey through the Milky Way.
How close will 3I/ATLAS come to Earth?
At its nearest point, 3I/ATLAS will pass about 1.8 astronomical units from Earth, or roughly 168 million miles, per Space.com reports. That is nearly twice the average distance between Earth and the Sun. According to the European Space Agency, the comet poses no risk to Earth or any other planet as it travels through the inner solar system.
The object is estimated to be anywhere between 440 meters and 3.47 miles wide, according to NASA; the exact size remains uncertain due to its distance. As it moves away from the Sun, astronomers expect it to grow dimmer, making observations more challenging in the coming weeks.
How astronomers are tracking the comet
3I/ATLAS is only the third confirmed interstellar object ever observed in the solar system. The first was 1I/‘Oumuamua in 2017, followed by 2I/Borisov in 2019. Unlike comets such as Halley’s Comet, which originate from the outer edges of the solar system, interstellar comets form around other stars and are ejected into space.
Because of its rarity, multiple observatories worldwide have focused their instruments on the comet. NASA astronomers, along with international teams, continue to track 3I/ATLAS using space-based telescopes. Recent images from the Hubble Space Telescope have helped refine estimates of its movement and structure.
What happens next in 3I/ATLAS’ journey
The comet will make a closer pass by Jupiter in March, coming within about 33 million miles of the gas giant. After that, it will gradually head outward. According to Paul Chodas, director of NASA’s Center for Near-Earth Object Studies, it will take until the mid-2030s for 3I/ATLAS to fully exit the solar system and return to interstellar space.
For now, astronomers are focused on collecting as much data as possible. Each observation adds to a small but growing record of interstellar objects.
FAQs
What is interstellar comet 3I/ATLAS?
3I/ATLAS is a comet that originated outside the solar system and is only the third confirmed interstellar object observed passing through it.
How close will 3I/ATLAS come to Earth?
The comet will pass at a distance of about 1.8 astronomical units, or roughly 168 million miles, posing no threat to Earth.
When is 3I/ATLAS’s closest approach to Earth?
Its closest approach occurs on 19 December, according to space agencies tracking its trajectory.
