After Earth, it must have been Venus, because that's the brightest and it moves in an obvious way.
Saturn was the first planet discovered to have rings. They were first observed by Galileo Galilei in 1610 through his telescope.
Prior to the observation of the planet Neptune by a telescope, the orbits of the other planets in our solar system were observed very closely, and subjected to mathematical analysis, and it was possible to figure out that the gravitational attraction of some undiscovered planet was affecting those orbits. Technically this phenomenon is called gravitational perturbation.
The third planet to be discovered was the dwarf planet Ceres, located in the asteroid belt between Mars and Jupiter. It was first observed in 1801 by Italian astronomer Giuseppe Piazzi.
It was in the18th century that Uranus was identified as a planet. It had been observed in the previous century, but was thought to be a star.
Neptune was discovered on September 23rd 1846, through mathematical prediction.
Neptune was discovered because of anomalies in the orbit of Uranus, indicating that another planet's gravitational pull was affecting Uranus's orbit. This led to the prediction and eventual discovery of Neptune in 1846 by Urbain Le Verrier and John Couch Adams.
Saturn was the first planet discovered to have rings. They were first observed by Galileo Galilei in 1610 through his telescope.
Neptune was discovered in 1846 through observations of Uranus. Uranus' orbit was seen to appear to alter slightly through the gravitational effect of another planet, which turned out to be Neptune.
Uranus was discovered by William Herschel in 1781. It had been observed and recorded before that, but Herschel was the first to realise it is a planet beyond Saturn.
Saturn was discovered in Pisa, Italy by Galileo Galilei in 1610. Galileo also observed and discovered Saturn's Rings
Prior to the observation of the planet Neptune by a telescope, the orbits of the other planets in our solar system were observed very closely, and subjected to mathematical analysis, and it was possible to figure out that the gravitational attraction of some undiscovered planet was affecting those orbits. Technically this phenomenon is called gravitational perturbation.
The third planet to be discovered was the dwarf planet Ceres, located in the asteroid belt between Mars and Jupiter. It was first observed in 1801 by Italian astronomer Giuseppe Piazzi.
Percival Lowell searched for Planet X, also known as Planet Nine or Planet Neun. He believed that anomalies in the orbits of Uranus and Neptune were caused by the gravitational pull of an unknown planet located beyond Neptune.
Jupiter
Neptune was discovered in 1846. Though it was first observed in 1612 by Galileo Galilei.
It was in the18th century that Uranus was identified as a planet. It had been observed in the previous century, but was thought to be a star.
Neptune was discovered on September 23rd 1846, through mathematical prediction.