“Space: the final frontier,” in the words of Star Trek character Captain Kirk, is a vast place that never ceases to amaze mankind. From the very first humans to our days, the wonders of the cosmos will always leave us in awe… and even more so when it comes to comets.
This weekend, perhaps one of the most exciting events for astronomy lovers will take place, as the 3I/Atlas interstellar comet makes its closest approach to Earth. The date? Friday, December 19th.
What is Comet 3I/Atlas?
3I/ATLAS isn’t your everyday comet, like your beloved Halley, but rather one of the rarest visitors astronomers have ever seen. The comet is classified as an interstellar object, which means it came from outside our solar system. Only two other interstellar objects have ever been confirmed before this: 1I/ʻOumuamua in 2017 and 2I/Borisov in 2019, making 3I/ATLAS the third known interstellar visitor in history.
NASA first spotted it on July 1, 2025, using the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in Chile. The comet is not bound to the Sun’s gravity, meaning it’s just passing through once and will never return.
Scientists think 3I/ATLAS might be billions of years old, maybe even older than our solar system itself, and it probably got ejected from its home star system long ago by gravitational interactions with giant planets or nearby stars. Tracing its exact birthplace isn’t possible, but its incoming direction points roughly from the region toward the constellation Sagittarius in the Milky Way.
Where to see comet 3I/Atlas from SoCal?
Unfortunately, due to how far the comet is traveling relative to Earth, it won’t be visible to the naked eye. Its brightness hovers around magnitude 10–11, which is too faint without optical aid. Still, you can catch 3I/ATLAS in the hours just before sunrise, using a telescope with at least 8 inches (200 mm) of aperture and a low-power eyepiece for a wider field of view, according to the official observing guide.
- Virtual Telescope Project (Dec. 19 Livestream): Watch 3I/ATLAS live as it makes its closest approach to Earth. The broadcast starts around 04:00 UTC and can be streamed on Virtual Telescope WebTV.
- RESET Desert Night-Sky Experience (Dec. 19): Guests enjoy twilight guided tours of the constellations, telescope viewing with Celestron, ambient soundscapes, movement art, and a welcome cocktail by Manojo Mezcal.
- Death Valley National Park: One of the darkest spots in SoCal, with minimal light pollution. Perfect for telescope observing of faint comets in the early morning, especially toward the east-northeast horizon.
- Anza-Borrego Desert State Park: Remote with wide-open skies, this park offers ideal conditions for amateur astronomers to track faint interstellar visitors like 3I/ATLAS with a medium or large telescope.