These light elements used to be abundant on Earth, but they were able to escape because of the relatively weak gravity and hot temperatures. On Jupiter, where gravity is enormously strong and temperatures are low, the elements remain.
    Jupiter’s elliptical orbit is on average more than five times farther from the Sun than Earth’s. This means Jupiter receives relatively little electromagnetic radiation from the Sun—less than 4 percent what the Earth receives—so the outer portions of the planet’s atmosphere are unimaginably cold, around 150 degrees Kelvin. Yet Jupiter is so large and reflects so much of the Sun’s light that it is the brightest object in the sky after the Sun,