As Professor Turing enters the room, he uses his wand to reveal many large images of the Solar System’s planets, which he placed in the classroom for this lesson. Students, some of whom are excitedly recounting their telescope viewing adventures, are intrigued by the planetary pictures, and by the time the professor reaches the lecturers desk, he has his students attention.
Good evening, everyone. I have heard very exciting tales of your planetary viewing, and I am pleased that many sought me out for help. We had a wonderful viewing earlier today; over half the class showed up, including most of Hufflepuff’s first-years.
We are nearing the end of the term, and I would love for everyone to end on a high note. As such, I am going to quickly go over our remaining schedule for the year. Two lessons from now is the Final Exam. It will be tougher than most assignments this week, but it will be completely doable if you focus on studying. On that day, we will also be discussing a few Astronomers whose work was mentioned this year, as sometimes when learning about the concepts, we lose sight of the people who are behind the discoveries. We will also have a guest lecturer who has a special connection to one of the featured Astronomers.
As for this lesson and next week’s lesson, we will be using the concepts learned this term to build bridges to concepts that will be featured in later terms. We will be covering many different planets and moons very quickly, but please feel free to speak up should I move too fast.
Beyond the Earth and the Moon
Image Source: OSU
So far this year, we’ve focused mostly on the magical relationships between the Earth and the Moon. While the Moon is very important to magic on Earth, there are also many other Astronomical bodies present in our Solar System. There is, of course, our Sun - the producer of all magic in the Solar System. Practically all magic that is reflected off Solar System planets has originated from the Sun. Also, the Sun pulls all of the Solar System planets, as well as objects such as asteroid belts and some comets, into orbits, which allow us to utilize the magical relationships we use today. In fact, the term “Solar System” includes the Sun and everything that revolves around it, from the great planets to the smallest rocks in the Asteroid Belt.
Planets of the Solar System
As for the planets in the Solar System, there are eight that are considered in the Magical world (and most of the Muggle world) to be planets. From closest to furthest from the sun, they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The four that are closest to the Sun are considered the Inner Planets, and they share similar features. Likewise, the last four are considered the Outer Planets, and they also share commonalities. There is also the dwarf planet Pluto. When the International Astronomical Union (IAU), one of the premier Muggle Astronomical associations, deemed that Pluto is not a planet in 2006, there was controversy, and there are some today who still consider Pluto to be a planet. Either way, Pluto is a part of the Solar System and thus has some effect on astronomical magic.
In addition to the many planets of the Solar System, there are also many moons. The Earth is unique in the Solar System in that it has exactly one moon, and our Moon is also relatively large compared to the Earth. In fact, the Earth’s Moon is so large that it is able to totally eclipse the Sun during a solar eclipse. Among the Inner Planets, there are only three moons - Earth’s Moon, and Mars’ potato-shaped moons, Phobos and Deimos. In contrast, many of the Outer Planets have a whole collection of moons, and new moons are still being discovered. For example, Jupiter currently has the most known moons at the time of this lesson. Of Jupiter’s 67 known moons, four of the most famous - the Galilean moons - were used by Galileo Galilei as evidence for a Sun-centered Solar System. Even Pluto, perhaps the most famous planetoid in the Solar System, has five moons. While moons have similar features, they also have unique properties. For example, Europa, perhaps the most well-known of the Galilean moons in the wizarding world, is covered in ice.
Furthermore, there are other features of the Solar System worth noting - asteroids belts, comets and the like. Then there is magic coming from outside of the Solar System - in particular, constellations for astrology. The whole universe contains objects that impact and emit magical energy, which makes Astronomy such an important and vital subject.
Inner Planets vs. Outer Planets
The eight planets in the Solar System are, as mentioned above, split into the Inner Planets and the Outer Planets. The Inner Planets refer to Mercury, Venus, Earth, and Mars, while the Outer Planets refer to Jupiter, Saturn, Uranus, and Neptune. The image I have presented above shows the eight planets in the Solar System scaled according to size, with the Inner Planets in the front and the Outer Planets in the back.
Perhaps the most obvious difference between the Inner Planets and the Outer Planets is this size difference - the Outer Planets are much larger than the Inner Planets. In fact, Earth is the largest of the Inner Planets even though it is quite small for a planet. That being said, the planets of Mercury, Venus, and Mars have much more of a magical effect on Earth than, say, Uranus or Neptune. This is because Mercury, Venus, and Mars have larger observed sizes since they are closer to the Earth, and thus the Inner Planets also have higher A.M.E.’s than Uranus or Neptune. Of all the Outer Planets, only Jupiter and Saturn were noticed by Astronomers before telescopes, and thus - due to their observed size and brightness - these planets have relatively noticeable A.M.E.’s and thus have a strong magical effect on the Earth.
Two other differences between the Inner Planets and Outer Planets are surface and composition. The surfaces of the Inner Planets are rocky, and although planets such as Venus and Earth - the two largest of the Inner Planets - have thick atmospheres, any spacecraft that attempted to land on the planets would be able to land on solid ground. Thus, all four of the Inner Planets have surface features. You will find landscapes of volcanic origin as well as craters. If you go deeper into these planets, you will also find that these planets are made of many heavier elements such as metals, and the cores are very metallic.
In contrast, the Outer Planets, while they are large, do not have hard surfaces. They are called “Gas Giants” because they are made of gas: a spacecraft that attempts to land on such a planet would not find a solid surface. Composition-wise, the Outer Planets are made of hydrogen and helium, the same components that make up our Sun. The Outer Planets also have ring systems and tend to have interesting moons.
We will continue discussing the Solar System next week. Thanks for coming to class today. Class is dismissed.