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.
Launched as GRAIL A and GRAIL B in September 2011, the probes were renamed Ebb and Flow by schoolchildren in Montana. The probes operated in almost circular orbit near the lunar poles at an altitude of approximately 34 miles, until their mission came to an end in December 2012. The distance between the twin probes altered a bit as they soared over areas of lesser and greater gravity that were caused by visible topological features on the Moon's surface, such as impact craters and mountains--as well as by masses that were secreted beneath the lunar surface. After a long and dangerous journey through the space between planets, the Cassini/Huygens Spacecraft reached Saturn on July 1, 2004. On December 25, 2004, the Huygens Probe was purposely liberated from the Cassini Orbiter. Huygens then began its historic descent through the dense blanket of golden-orange fog to at last lift the veil hiding Titan's long-hidden face. Moon in a Fire element (Aries, Leo or Sagittarius) will react directly and with enthusiasm to anything that they can pioneer or have a leading part in directing change or something new. Emotions driven by fire can be explosive, impatient and restless but will feel at home in having a mission and implementing action in getting things off the ground and aiming for a goal.