According to a new study published in Nature Astronomy, Jupiter was once approximately twice its current size and possessed a magnetic field 50 times stronger than it has today. By analyzing the slightly tilted orbits of Jupiter's inner moons Amalthea and Thebe, researchers from Caltech and the University of Michigan determined that about 3.8 million years after the solar system began forming, the gas giant had a volume equivalent to over 2,000 Earths before eventually shrinking to its present dimensions.

According to a new study published in Nature Astronomy, Jupiter was once approximately twice its current size and possessed a magnetic field 50 times stronger than it has today. By analyzing the slightly tilted orbits of Jupiter's inner moons Amalthea and Thebe, researchers from Caltech and the University of Michigan determined that about 3.8 million years after the solar system began forming, the gas giant had a volume equivalent to over 2,000 Earths before eventually shrinking to its present dimensions.