The Planets

• Type: Celestial Body, Subject of Astronomy
• Owners: N/A
• Maker: N/A

The planets are large celestial bodies that orbit the Sun within the Solar System. In the wizarding world, as in the Muggle world, they are primarily observed at night through the use of telescopes. The study of planets is a key component of the Astronomy curriculum at Hogwarts School of Witchcraft and Wizardry, which takes place in the Astronomy Tower, the school's tallest tower. Students are expected to learn the names of the planets, their orbital paths, and the names of their respective moons. Specific planets mentioned in the novels include:

• Mars: Noted by Centaurs for its brightness, which they consider a powerful omen.
• Jupiter: Its moons are a specific topic on the fifth-year O.W.L. exam.

During the practical portion of the Astronomy O.W.L., students are given a blank star chart to fill in, requiring them to identify and map the positions of planets and stars as seen from their telescopes. A magical model of the moon was also present during Harry Potter's exam.

While planets do not possess inherent magical properties in the way an enchanted object does, their movements and positions are of profound significance in certain branches of magic, particularly Divination.

• Use in Astronomy: The primary use of planets is academic. Hogwarts students study them to understand the cosmos. This involves precise mathematical calculations of their movements and memorization of their characteristics, such as the composition of their atmospheres and the number and names of their moons. This knowledge is considered a fundamental part of a wizarding education.
• Use in Divination: The positions of the planets are crucial for astrological Divination. Centaurs, in particular, are masters of reading the future in the night sky. They believe that the movements of the planets are not random but are omens of future events on Earth. The phrase “Mars is bright tonight,” uttered by Ronan and later Firenze, is used to signify that a period of great violence and war is imminent. Professor Trelawney's teachings in Divination also touch upon the influence of planets on an individual's fate, though her methods are often viewed with more skepticism.

The study of planets has been a part of the Hogwarts curriculum for centuries. The most detailed account of its academic role comes from Harry Potter's fifth year. During the O.W.L. examinations, Harry and his classmates took their practical Astronomy exam at midnight. They were tasked with interpreting a star chart based on their observations. Harry, distracted and under pressure, notably struggled to remember the names of Jupiter's moons. This particular exam became infamous not for its difficulty, but for its interruption. As the students worked, Professor Umbridge and a group of Ministry of Magic officials, including John Dawlish, attempted to stun Rubeus Hagrid and forcibly remove him from the school grounds. The resulting battle led to Professor McGonagall being hit with multiple Stunning Spells while defending Hagrid, causing her to be hospitalized at St. Mungo's Hospital for Magical Maladies and Injuries.

The planets serve two main functions in the narrative. First, they ground the wizarding world with a familiar, scientific framework, demonstrating that magic and science-based subjects like Astronomy coexist in a wizard's education. Second, and more importantly, they are a powerful narrative device for foreshadowing and theme. The Centaurs' observation that “Mars is bright tonight” in both Harry Potter and the Philosopher's Stone and Harry Potter and the Order of the Phoenix directly links the planet of war with the escalating conflicts of the First Wizarding War and Second Wizarding War. This celestial omen underscores the gravity of Lord Voldemort's return and lends an air of ancient, unavoidable fate to the events unfolding on the ground. The disruption of the Astronomy O.W.L. also serves as a critical turning point, showcasing the Ministry of Magic's tyrannical overreach and solidifying the students' and teachers' opposition to Umbridge.

• In Roman mythology, Mars is the god of war, a direct parallel to the omen of conflict the Centaurs associate with the planet. J.K. Rowling frequently drew upon classical mythology for names and concepts.
• According to Pottermore, the Astronomy classroom contains a magical, hovering model of the complete Solar System, which is enchanted to accurately reflect the real-time movements of the celestial bodies. (Pottermore)