Io's metallic core makes up approximately 20% of its mass. Depending on the amount of sulfur in the core, the core has a radius between 350 and 650 km (220â400 mi) if it is composed almost entirely of iron, or between 550 and 900 km (340â560 mi) for a core consisting of a mix of iron and sulfur.
The early history of the automobile can be divided into a number of eras, based on the prevalent means of propulsion. Later periods were defined by trends in exterior styling, size, and utility preferences. In 1769 the first steam-powered automobile capable of human transportation was built by Nicolas-Joseph Cugnot.
Why was the automobile invented? A: The automobile was invented to provide a form to transport people and cargo that was quicker and more convenient than those that existed at the time, such as horses, horse-drawn carriages, trains and boats.