Stargazers and scientists are getting a holiday present from the cosmos this week.
3I/ATLAS, an interstellar comet, will get “closest” to Earth on Friday, December 19, as part of its journey across the galaxy.
Let’s break the facts of this natural phenomena down because it sounds like it could be the plot of an exciting science fiction thriller.
What is an interstellar comet?
Much like a Christmas tree, planets in our Solar System revolve around our star, the sun.
It’s not the only planetary system out there. Our galaxy, the Milky Way, contains other systems, and if you zoom out even further, there are even more.
The comet 3I/ATLAS is labeled interstellar because it comes from outside our star system and is not gravitationally bound to the sun. It’s on an elliptical vacation of sorts, exploring new locations with a greater freedom than the other objects surrounding it.
When was 3I/Atlas discovered?
Scientists only recently discovered 3I/ATLAS, on July 1, 2025.
The Asteroid Terrestrial-impact Last Alert System survey telescope, funded by NASA and located in Rio Hurtado, Chile, first laid eyes on the object. This observation caused scientists to go back and look over records from other Atlas telescopes to learn more.
These pre-discovery findings found evidence of the comet dating back to June 14, 2025.
The comet got its name because it is a tradition to name objects after the people or system that discover them. In this case, it was named after Atlas. The 3 and the I tell the world this is the third interstellar object found.
How close will 3I/ATLAS actually get?
On Friday, 3I/ATLAS will get the closest to Earth in its orbit, but close is a relative term.
It will cross within 167 million miles of our planet. To put that in perspective, that is around two times the distance between the Earth and the Sun. The comet poses no danger to Earth, meaning there’s no need to hire a ragtag group of oil drillers à la the 1998 film Armageddon.
How best to view 3I/Atlas
Unfortunately, 3I/ATLAS cannot be viewed by the naked eye. Dedicated stargazers will need a small telescope. But the silver lining is that the comet will hang around until spring. For best results, view in the early, predawn hours.
According to NASA, those who are extra enthusiastic and planning a Friday adventure should focus on the bright star Regulus in the constellation Leo, as 3I/ATLAS should appear near that location.
For those who are without a telescope and would rather sleep in, NASA has done the work for you. You can visit the NASA website to view 3I/ATLAS from many different angles. Maybe the pictures will inspire you to write the next great science fiction tale.
Finally, NASA’s “eyes on the solar system” tool lets you view a simulated live version of 3I/ATLAS as it hurls through space.
