What is heliocen?

Who was an astronomer during the Renaissance? What jeweler donated the famous Hope Diamond to the Smithsonian in 1958? If earth had no atmosphere what would the temperature be? What comes after a Leo in the zodiac calendar? What happens to the length of the shadows as the angles of the sun's rays increase or decrease? Is the moons orbit in the same 3d plane as earths orbit? Which planet does Luke Skywalker come from? Could a solar flare potentially destroy electronics? What type of eclipse occurs when the Earth Moon and Sun are lined up in the order? What happens to the gravitational force if distance increases? How many rings does the sun have? Can a star fall on earth? Which process is required to allow a gravitationally-collapsing gas cloud to continue to collapse? Nickel with 13 stars? Where does the sun go after its sunset? When did the oxygen tank burst on Apollo 13? What is a space helmet made of? Which of the thinkers from the scientific revolution first proposed a heliocentric theory that Earth revolves around the sun? When did they start building the space station? What damage would a baseball size meteor cause to earth?