The mysterious comet from deep space, called 3I/ATLAS, has entered our Solar System, puzzling scientists with its strange chemicals and possible origins in the Milky Way’s main disc
The mysterious new comet from deep space, known as 3I/ATLAS, is continuing to baffle scientists with its strange mix of chemicals. As a result, a top theoretical physicist has said 3I/ATLAS likely comes from the main part of our own Milky Way galaxy.
First detected by the ATLAS survey in Chile in July 2025, 3I/ATLAS has already sparked intense scientific debate about its origins and composition. Regularly writing in Medium, Harvard astrophysicist Avi Loeb recently highlighted a paradox at the heart of the object’s identity.
Astronomers have confirmed the discovery of 3I/ATLAS (also known as C/2025 N1), the third known interstellar object to enter our Solar System.
Loeb consequently wrote his latest blog post: “The Galactic orbit of 3I/ATLAS suggests a likely origin in the disc of the Milky-Way galaxy. The composition of the coma of 3I/ATLAS in terms of carbon, oxygen and nitrogen — based molecules, implies that most of its mass is associated with heavy elements.”
Moreover, 3I/ATLAS is seemingly moving in a way that shows it comes from the main part of our galaxy, and it could be much older than our own Solar System. It could be maybe up to 14 billion years old.
What’s inside this comet is also surprising. Powerful telescopes have found that it’s packed with carbon dioxide, along with other gases like carbon monoxide, water, and small amounts of chemicals like methanol and cyanide.
In fact, it has about 16 times more carbon dioxide than comets we usually see, and it gives off a lot of nickel gas but no iron, which is very unusual.
Many are wondering how the comet could exist at all.
Some clues suggest it was made in a part of the galaxy with very few heavy elements, but the gases coming off the comet show it actually has a lot of these “metals”.
This doesn’t quite add up, and scientists are trying to figure out how such a comet could have formed and ended up here.
The solid core of 3I/ATLAS is pretty big, somewhere between 300 metres and over a kilometre wide.
As scientists keep studying it, they hope this rare visitor will help us learn more about where objects like this come from and how they travel through space.
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