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.
Discovered on March 31, 2005, by a team of planetary scientists led by Dr. Michael E. Brown of the California Institute of Technology (Caltech) in Pasadena, Makemake was initially dubbed 2005 FY 9, when Dr. Brown and his colleagues, announced its discovery on July 29, 2005. The team of astronomers had used Caltech's Palomar Observatory near San Diego to make their discovery of this icy dwarf planet, that was later given the minor-planet number of 136472. Makemake was classified as a dwarf planet by the International Astronomical Union (IAU) in July 2008. Dr. Brown's team of astronomers had originally planned to delay announcing their discoveries of the bright, icy denizens of the Kuiper Belt--Makemake and its sister world Eris--until additional calculations and observations were complete. However, they went on to announce them both on July 29, 2005, when the discovery of Haumea--another large icy denizen of the outer limits of our Solar System that they had been watching--was announced amidst considerable controversy on July 27, 2005, by a different team of planetary scientists from Spain. A Distant, Dusty Moon. Titan experiences changing seasons--just like Earth. In particular, Titan's seasons change around the equinox, when our Sun passes Titan's equator. At this time, huge clouds can form in tropical areas, resulting in violent methane storms. Cassini observed these ferocious methane storms during several of its flybys over Titan. The moon's orbit. The moon's orbit is not on the same plane as the earth's orbit around the sun. If it were, every time we had a new moon we would have a solar eclipse, and every time we had a full moon we would have a lunar eclipse. Instead, the moon travels in a track that goes well above and well below the earth. Still, on occasion it will travel in between the sun and the earth and in this case, there will be an eclipse.