Hubble and Webb Team Up to Spy Tiny Frozen Worlds beyond Neptune

For the first time, astronomers combined Hubble and Webb space telescopes to hunt down some of the smallest, faintest objects ever spotted in the outer Solar System.

This artist’s concept depicts a trans-Neptunian object. Image credit: NASA / ESA / Leah Hustak, STScI.

Two teams of astronomers led by University of Victoria and Northern Arizona University PhD candidates used Hubble’s visible-light vision alongside Webb’s infrared eye to examine 27 newly found trans-Neptunian objects (TNOs).

These tiny bodies are icy relics left over from the Solar System’s construction phase, before planetesimals ever merged into full planets.

The smallest was just 5 km (3 miles) wide, and one was so dim it’s comparable to spotting fireflies on the Moon from Earth.

These objects matched the colors of their much larger TNO cousins, suggesting collisions haven’t reshaped their surfaces as much as scientists expected.