More than 100 million times dimmer than what can be seen by the naked eye, far-out Trans-Neptunian Objects (TNOs) are small, faint, icy bodies orbiting the Sun beyond Neptune’s orbit. Now, in the deepest TNO studies to date, researchers analyzed the color, composition, and size distribution of 27 newly discovered TNOs—some of them the smallest and faintest ever directly seen. 

Using NASA’s Hubble and James Webb Space Telescopes, the teams measured the objects’ colors, which are like a fingerprint of the surface composition, as well as their sizes, and determined their orbits. What they found was the best view yet into an early stage of planet-building in our solar system. Working together to detect and characterize these TNOs, Hubble and Webb provided more insight into these tiny objects than either could on its own.