What is heliocen?

What is 3 of Galileos discoveries or inventions? What is the different of umbra and penumbra? Length of a yeaR ON Mars? Where did April get its name? What is the reaction force that sends a space shuttle into space? Do clouds pour clean water? What is the relationship of a stars temperature and size? Where is the worlds biggest stalactite? What is the elevation of the north star? Which describes Zeus? Does the moon have gravity on it? What is unusual about the Lilliputians' size? What does water vapour become in the sky? Will the sun implode or explode? The amount of light and warmth a planet from the sun depends on what factors? What do you wear in space? What kind of elements are found in a low mass star? When was Apollo 20 launch? What was the first space craft made? How many Jupiters would it take to fill up the sun?