The Solar System formed 4. 6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The vast majority of the system’s mass is in the Sun, with the majority of the remaining mass contained in Jupiter. The four smaller inner planets, Mercury, Venus, Earth and Mars, are terrestrial planets, being primarily composed of rock and metal. The four outer planets are giant planets, being substantially more massive than the terrestrials. The two largest, Jupiter and Saturn, are gas giants, being composed mainly of hydrogen and helium; the two outermost planets, Uranus and Neptune, are ice giants, being composed mostly of substances with relatively high melting points compared with hydrogen and helium, called volatiles, such as water, ammonia and methane. All eight planets have almost circular orbits that lie within a nearly flat disc called the ecliptic.
Have you ever wondered what may be the purpose of the moon? Well, the moon is the shiny beacon that lights up the night as the sun lights up the day. This amber body is quite shy and doesn't always show itself, but when it does, the moon's brilliance overpowers the darkness. The surface of the moon inspires astronomers around the globe who religiously watch as our incandescent orb passes serenely through its natural cycle, but if you are an avid planet observer you will come to realise that the reflecting light from the moon through the telescope lens may interfere with your ability to clearly view even our closest planets. For this reason many planet watches believe the new moon cycle is the perfect time to catch a glimpse of another world. The need to comprehend and explain our origins--the world of natural phenomena--cannot be properly viewed as exclusively scientific. Instead, it should be viewed as something generally human. Through enchanting, magical narratives involving super-human heroes and heroines, as well as anthropomorphic gods and goddesses, ancient pre-scientific societies attempted to explain and make some order out of the mysterious complexities of the Cosmos. Earth's Moon has always held a place of special fascination for our species, inspiring our human imagination to escape its troubling limitations and--as we search beyond our Earthbound lives--help us to move towards an understanding of who we are, in all our human complexity. Therefore, ancient gods and goddesses mimic our bewitching Moon's unending, gentle tug on the forces of life. In this sense, it may be detrimental to completely dismiss these ancient myths--ascribing them to an unsophisticated and archaic past. "We developed new operations methods for INMS for Cassini's final flight through Enceladus' plume. We conducted extensive simulations, data analyses, and laboratory tests to identify background sources of hydrogen, allowing us to quantify just how much molecular hydrogen was truly originating from Enceladus itself," explained Dr. Rebecca Perryman in the April 13, 2017 SwRI Press Release. Dr. Perryman is INMS operations technical lead.