"For the smaller craters, it's like if you're filling a bucket, eventually your bucket gets full, but if you keep pouring cups of water into the bucket, you can't tell how many cups of water beyond full you've gone. Looking at the larger craters at the subsurface might give us insight, because that 'bucket' isn't full yet," Dr. Soderblom added. The findings of the two missions are presented in papers published on April 13, 2017, by planetary scientists with NASA's Cassini mission to Saturn and the venerable Hubble Space Telescope (HST). In one of the papers, Cassini scientists announced their discovery that a form of chemical energy life can feed on appears to exist on Enceladus. In the second paper, HST researchers report additional evidence of plumes erupting from Jupiter's moon, Europa, whose fascinating frozen crust of ice resembles a cracked eggshell. It has long been recognized by planetary scientists that beneath Europa's bizarre cracked shell of ice, there is a sloshing global ocean of liquid water. When Jupiter was born along with the rest of our Solar System, approximately 4.56 billion years ago, it twinkled like a star. The energy that it emitted--as a result of tumbling surrounding material--made Jupiter's interior searing-hot. In fact, the larger Jupiter grew, the hotter it became. At long last, when the material that it had drawn in from the whirling, swirling surrounding protoplanetary accretion disk--made up of nurturing dust and gas--was depleted, Jupiter may well have attained the enormous diameter of over 10 times what it has today. It also may have reached a truly toasty central temperature of about 50,000 Kelvin. During that long ago era, Jupiter twinkled, glittered, and sparkled like a little star, shining ferociously with a fire that was approximately 1% that of our much more brilliant Sun today.