How much is neil Armstrong's signature worth?

Why do helicopters have a difficult time flying above 6000 meters? What is the longest distance a rocket has traveled from earth? Why is the moons rotation period longer then Earths? When the clocks go back an hour will there be more light in the morning? Who led the expedition that proved that the world is round? Triton is a moon of which planet? What space ship did neil amstrong take to the moon? What is the danger of a solid fuel designed for a rocket that has an air pocket inside? What part falls off after takeoff on a rocket? Is the number of hours of daylight the same all over the world? How does Coriolis effect influence weather and climate? What is shortitude? Are there more Stars or Planets? Why is there a star on top of the Christmas tree? What continent on earth is similar to the moon's surface area? What do astronauts do in the moon? What is the navigational tool with a needle called? How heavy do astronauts have to be to be in a rockets? Why is it yellow outside before a tornado? Why do raindrops vary in size?