Illustration: Path of comet C/2025 K1 (ATLAS)

This diagram shows the path the long-period comet C/2025 K1 (ATLAS), or K1 for short, took as it swung past the Sun and began its journey out of the Solar System. On November 10, 2025, Hubble captured the inset image of the fragmenting comet. Hubble took this image just a month after K1’s closest approach to the Sun, called perihelion.

During perihelion, a comet experiences its most intense heating and maximum stress. Just past perihelion is when some long-period comets like K1 tend to fall apart. K1’s perihelion was inside Mercury’s orbit, about one-third the distance of the Earth from the Sun. This is the first time Hubble has witnessed a comet so early in the process of breaking up.

[Image description: Diagram showing comet K1’s path. With the Sun near middle right of image, truncated nearly circular orbits of Mercury, Venus, Earth, and Mars appear against black background. K1’s tight parabolic curve, marked by solid, light blue curving line, illustrates how K1 swooped toward the Sun from above. It curved around the Sun, coming closest inside Mercury’s orbit, and continued its outbound journey.