The Solar System provides the only known example of a habitable planet, the only star we can observe close-up, and the only worlds we can visit with space probes. Pluto was considered. . Our planetary system is called “the solar system” because we use the word “solar” to describe things related to our star, after the Latin word for Sun, "solis. [11] The system formed about 4. 6 billion years ago when a dense region of a molecular cloud collapsed, creating the Sun and a protoplanetary disc. . Millions of Americans are deciding to power their homes with solar energy—especially as costs have decreased—but an investment in solar energy generates more than just clean energy. The universe is filled with billions of star systems.
