24/7 Space News
IRON AND ICE
Newly discovered interstellar object 'may be oldest comet ever seen'
illustration only
Newly discovered interstellar object 'may be oldest comet ever seen'
by Sam Tonkin
London, UK (SPX) Jul 14, 2025

A mystery interstellar object discovered last week is likely to be the oldest comet ever seen - possibly predating our solar system by more than three billion years, researchers say.

The "water ice-rich" visitor, named 3I/ATLAS, is only the third known object from beyond our solar system ever spotted in our cosmic neighbourhood and the first to reach us from a completely different region of our Milky Way galaxy.

It could be more than seven billion years old, according to University of Oxford astronomer Matthew Hopkins - who is discussing his findings at the Royal Astronomical Society's National Astronomy Meeting 2025 in Durham - and may be the most remarkable interstellar visitor yet.

Unlike the previous two objects to enter our solar system from elsewhere in the cosmos, 3I/ATLAS appears to be travelling on a steep path through the galaxy, with a trajectory that suggests it originated from the Milky Way's 'thick disk' - a population of ancient stars orbiting above and below the thin plane where the Sun and most stars reside.

"All non-interstellar comets such as Halley's comet formed with our solar system, so are up to 4.5 billion years old," Hopkins said.

"But interstellar visitors have the potential to be far older, and of those known about so far our statistical method suggests that 3I/ATLAS is very likely to be the oldest comet we have ever seen."

The object was first spotted on 1 July 2025 by the ATLAS survey telescope in Chile, when it was about 670 million km from the Sun.

Hopkins' research predicts that, because 3I/ATLAS likely formed around an old, thick-disk star, it should be rich in water ice.

"This is an object from a part of the galaxy we've never seen up close before," said Professor Chris Lintott, co-author of the study and presenter of the BBC's The Sky at Night.

"We think there's a two-thirds chance this comet is older than the solar system, and that it's been drifting through interstellar space ever since."

As it approaches the Sun, sunlight will heat 3I/ATLAS's surface and trigger cometary activity, or the outgassing of vapour and dust that creates a glowing coma and tail.

Early observations already suggest the comet is active, and possibly larger than either of its interstellar predecessors, 1I/'Oumuamua (spotted in 2017) and 2I/Borisov (2019).

If confirmed, this could have implications for how many similar objects future telescopes, such as the new Vera C. Rubin Observatory, are likely to detect. It may also provide clues about the role that ancient interstellar comets play in seeding star and planet formation across the galaxy.

"We're in an exciting time: 3I is already showing signs of activity. The gases that may be seen in the future as 3I is heated by the Sun will test our model," said co-author Dr Michele Bannister, of the University of Canterbury in New Zealand.

"Some of the biggest telescopes in the world are already observing this new interstellar object - one of them may be able to find out!"

The discovery of 3I caught the team by the surprise. It happened as they were gearing up for the beginning of survey operations with the Vera C. Rubin Observatory, which their model predicts will discover between 5 and 50 interstellar objects.

"The solar system science community was already excited about the potential discoveries Rubin will make in the next 10 years, including an unprecedented number of interstellar objects," said co-researcher Dr Rosemary Dorsey, of the University of Helsinki.

"The discovery of 3I suggests that prospects for Rubin may now be more optimistic; we may find about 50 objects, of which some would be similar in size to 3I. This week's news, especially just after the Rubin First Look images, makes the upcoming start of observations all the more exciting."

The team's findings come from applying a model developed during Hopkins' doctoral research, which simulates the properties of interstellar objects based on their orbits and likely stellar origins.

Just a week before the comet's discovery, Hopkins had defended his thesis, and when 3I/ATLAS was announced, he was set to go on holiday. Instead, he found himself comparing real-time data to his predictions.

"Rather than the quiet Wednesday I had planned, I woke up to messages like '3I!!!!!!!!!!'," said Hopkins. "It's a fantastic opportunity to test our model on something brand new and possibly ancient."

The researchers' model, dubbed the Otautahi-Oxford Model, marks the first real-time application of predictive modelling to an interstellar comet.

For those keen to catch a glimpse of 3I/ATLAS, it should be visible through a reasonably-sized amateur telescope in late 2025 and early 2026.

Related Links
The Galactic Interstellar Object Population in the LSST
Asteroid and Comet Mission News, Science and Technology

Subscribe Free To Our Daily Newsletters
Tweet

RELATED CONTENT
The following news reports may link to other Space Media Network websites.
IRON AND ICE
Comet believed to be 3 billion years older than our solar system
Washington DC (UPI) Jul 11, 2025
Scientists believe an interstellar comet discovered earlier this month could be one of the oldest that astronomers have ever encountered. University of Oxford scientists said the 3I/ATLAS comet could be some 3 billion years older than our solar system, which is believed to be 4.5 billion years old. The comet was first reported by NASA's Asteroid Terrestrial-impact Last Alert System or ATLAS survey telescope in Chile on July 1, while so-called "pre-discovery" observations date back to Jun ... read more

IRON AND ICE
ISS update: Crew-11 enters quarantine three weeks before launch

Austrian space diver Felix Baumgartner was 'born to fly'

Jensen Huang, AI visionary in a leather jacket

Club Med taps ex-Carrefour executive as new CEO

IRON AND ICE
SpaceX scrubs launch of 2 SES mPOWER satellites

Rocket Lab partners with Bollinger Shipyards to transform Neutron sea recovery platform

Lunar soil shows promise for in-situ oxygen and fuel production

Boeing looks for Starliner fixes despite costs, ISS age

IRON AND ICE
Ancient river systems reveal Mars was wetter than we thought

The Mars mission that could prep for a human landing

Was Mars doomed to be a desert? Study proposes new explanation

China prepares for Mars sample return with HKU astrobiologist on mission team

IRON AND ICE
Six Chinese universities to launch new low altitude space major this fall

International deep space alliance launched in Hefei China

China launches international association to boost global access to deep space research

Chinese Long March Rockets Make International Debut at Paris Air Show

IRON AND ICE
Surrey launches new Space Institute to drive mission-ready innovation and skills for UK space sector

Eutelsat strikes global satellite internet deal with UK govt

Globalstar selects SpaceX to launch final replacement satellites

UK invests $191 mn in European satellite firm Eutelsat

IRON AND ICE
UK opens competitive bid for GBP 75 million orbital cleanup mission

Bearings Used in Space Technologies: Engineering for the Final Frontier

Microsoft halts China-based tech support for Pentagon systems

York to Acquire Operations to Boost Ground Connectivity and Mission Delivery

IRON AND ICE
Alien life clues may emerge from deep sea volcanic vents on Earth

Scientists uncover mechanism that causes formation of planets

NASA Research Shows Path Toward Protocells on Titan

Astronomers observe birth of a solar system for first time

IRON AND ICE
Rare Trans Neptunian Object Reveals Unexpected Orbital Dance with Neptune

Fossil object 2023 KQ14 challenges Planet Nine theory with unique distant orbit

UH Researchers Help Solve Uranus Heat Mystery

Unexpected Dust Patterns Found on Uranus Moons Confound Scientists

Subscribe Free To Our Daily Newsletters




The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.