27 tiny worlds beyond Neptune: Hubble and Webb find the solar system's time capsules

Beyond Neptune, in the cold dark at the edge of the solar system, two great telescopes have been hunting together. NASA's Hubble and James Webb have identified 27 previously unknown trans-Neptunian objects — icy bodies left over from the solar system's formation more than 4 billion years ago — in what researchers describe as the deepest survey of this population yet. By combining Hubble's visible-light images with Webb's infrared view, astronomers could study the objects' sizes, colours and orbits; Webb picked out bodies as small as about 5 kilometres across, and found fewer small objects than some models predicted. The findings, reported in two studies in The Astronomical Journal, are a rare direct look at the raw material the planets were built from.