The James Webb Space Telescope (JWST) has just solved a 20-year-old mystery about how ancient stars could host massive planets.
In the early 2000s, the Hubble Space Telescope observed the oldest planet ever, an object 2.5 times as large as Jupiter that formed in the Milky Way 13 billion years ago, less than a billion years after the universe was born. The discovery of other old planets soon followed. This puzzled scientists, as stars in the early universe should have consisted mostly of light elements like hydrogen and helium, with almost none of the heavy elements — things like carbon and iron — that make up planets.
