NASA released close-up images of the interstellar comet 3I/Atlas, which is making a brief pass through the solar system.

The comet, only the third confirmed interstellar object, recently passed 18 million miles from Mars, where multiple NASA and ESA spacecraft observed it.

Ground-based telescopes and the James Webb Space Telescope are also tracking the comet, which will come closest to Earth—167 million miles away—in mid-December before returning to interstellar space.

Estimates suggest the comet measures between 440 meters and 5.6 kilometers across and may have originated in a star system older than our own, offering scientists a rare glimpse into the deep past, The Guardian has reported.

NASA emphasized that 3I/Atlas is a natural comet, not an alien spacecraft, despite public speculation.