A "baby" exoplanet, discovered emerging from its cosmic cocoon around a nearby star, is the youngest alien world ever seen, a new study reveals. The planetary infant is less than 1 million years old and could help researchers study how other planets, including our own, took shape. The juvenile world, dubbed Elias 2-24 b, orbits a newly formed star around 450 light-years from Earth. It is somewhere between two and four times as massive as Jupiter and almost twice as far from its home star as Neptune is from the sun. Astronomers spotted initial signs of the hefty exoplanet in 2017, when they noticed a small gap in the star's protoplanetary disk — the swirling ring of gas, dust and other stella...