Order the Planets (and Other Heavenly Bodies) Quiz

The existence of Earth has been known since the dawn of civilization. It is the home planet of life in the Milky Way Galaxy and from which all other heavenly bodies have been discovered. It is the only known planet in the Solar System, if not the universe, capable of sustaining life on a large scale.

The exact date of the discovery of Mars is unknown but it was for sure documented by 1534 BCE which is the year ancient Egyptians noted that Mars seemed to wander in the sky. Its existence was certainly known before then although an exact date cannot be pinpointed.

The Andromeda galaxy was first documented in 964 by Persian astronomer Abd al-Rahman al-Sufi who described it as a nebula. It was not until centuries later in 1755 that astronomers suspected Andromeda might be a separate galaxy. The debate on this issue went on for over a century.

Titan, Saturn's largest moon, was discovered on March 25, 1655 by Christiaan Huygens. Huygens discovered Titan while he was experimenting with improving his telescope's technology. It was the first moon of Saturn to be discovered and the first outside of Earth and Jupiter.

The first known recording of Uranus came in 1690 when John Flamsteed first observed it. However, he mistakenly thought it was a star. In 1781, William Herschel was better able to observe Uranus. However, he mistook it for a comet until Anders Johan Lexell noted its orbit.

Neptune was discovered in 1846 when Johann Gottfried Galle noticed an unusual occurrence in the orbit of Uranus that indicated, to him, another planet existed beyond Uranus. Prior to this, there was speculation that Neptune had been observed by Galileo over two centuries earlier.

However, this could not be confirmed because Galileo's observations as recorded do not seem to describe a planet.

Triton, the largest moon of Neptune, was discovered just seventeen days after Neptune, an extremely quick discovery compared to other planets' moons. British astronomer, William Lassell, immediately began searching for moons once the discovery of Neptune was announced.

He discovered Triton on October, 10 1846. Lassell also recorded discovering rings, although this appears to be incorrect. Neptune does have rings but not in the way Lassell described them nor is it believed the technology existed in Lassell's time to have seen the rings.

Phobos, the largest moon of Mars, was not discovered until much later in time - well after the discovery of much further away heavenly bodies. Prior to the discover of both of Mars' moons, Phobos and Deimos, in 1877, it was widely speculated that Mars had two moons because Earth had one and Jupiter had four. "Gulliver's Travels", written in 1726, explicitly refers to two moons of Mars.

The reason it took so long to discover Mars' moons is that they are very small in size compared to other moons and orbit very close to Mars.

Pluto was discovered in 1930 by Clyde Tombaugh, who resumed the search for so-called Planet X after the death of Percival Lowell who funded much of the search. In 2006, Pluto was infamously demoted from a planet to a dwarf planet after new criteria were established on what constitutes a planet.

The Kuiper Belt is a rough ring of celestial bodies located beyond Pluto. Its existence had long been speculated about but it was confirmed in 1992 when the minor planet Albion was discovered. Since then, the definition of the Kuiper Belt has expanded (though not universally so) to include bodies such as Pluto and Charon.