Final answer:
It is true that metallic hydrogen is thought to exist at the core of gas giant planets like Jupiter, where high internal pressures cause hydrogen to behave like a metal.
Step-by-step explanation:
It is indeed true that metallic hydrogen is thought to exist at the cores of gas giant planets like Jupiter. The incredibly high pressures found thousands of kilometers beneath the cloud layers of these planets compress hydrogen into a state where it begins to exhibit properties of a metallic substance. This transformation is due to the free movement of electrons, akin to the behavior of electrons in metals on Earth, which makes these metals potent conductors of electricity. Moreover, within Jupiter, a substantial portion of the interior is believed to be composed of this liquid metallic hydrogen. Additionally, for planets like Saturn, which is less massive than Jupiter, there is only a small volume of metallic hydrogen, while most of its interior remains liquid. On the other hand, Uranus and Neptune's size doesn't allow for enough internal pressure to liquefy hydrogen. The existence of metallic hydrogen within these planets contributes to the unique magnetic fields that the gas giants possess.