Image: the star TRAPPIST-1a and its 7 telluric planets represented with their respective sizes (the distance to the star is not respected).
NB: TRAPPIST (Transiting planets and planetesimals small telescope) is a network of 2 robotic telescopes. A telescope is located at the La Silla Observatory (Chile) and the second telescope at Oukaïmeden (Morocco).
The resonance of the planets
In the confused and turbulent world around us, there are regularities that make sense out of apparent chaos.
For example, we notice that the Earth rotates regularly around the Sun in one year, that the days follow the nights, that the nautilus builds its shell in spirals or that the cells of the bees are hexagonal...
All civilizations have been on the lookout for these patterns, rhythms, repetitions and patterns that amaze and reassure us. This allows us to believe that there is an order or purpose in our observable Universe.
At all times, these regularities, contingent or accidental, have inspired philosophers, physicists, mathematicians and especially musicians.
When we talk about regularities we think about sounds. In music an octave corresponds to a doubling of frequency f, 2f, 3f, etc. These multiple frequencies of a given frequency are called harmonics.
For example, the note do has a frequency of 260 Hz, the next do is 520 Hz. The ground note has a frequency 1.5 times the do, the next ground is equal to 3 times the do, etc. These regularities are sufficient to fix the musical harmony.
The solar system discovered in 2016 by the transits method, is 7.6 billion years old and is located in the constellation of Aquarius at 39.5 light-years.
This system is composed of an ultra-cold dwarf star called TRAPPIST-1a and at least 7 rocky planets (TRAPPIST-1b, TRAPPIST-1c, TRAPPIST-1d, TRAPPIST-1e, TRAPPIST-1f, TRAPPIST-1g, TRAPPIST-1 1h).
Three of them are located in the habitable zone of the star and TRAPPIST-1e has a density close to that of the Earth, and it is probably endowed with an iron core and a liquid or icy ocean.
Using a computer model, scientists simulated planetary orbits and discovered that the 7 planets are in perfect orbital harmony.
In other words, each planet has simple relationships with the orbital periods of its neighbors. When the outermost planet trappist-1h traverses 2 orbits, its neighbor trappist-1g traverses 3 orbits and trappist-1f 4 orbits and tarppist-1e 6 orbits and trappist-1d 9 orbits and trappist-1c 15 orbits and trappist-1b traversed 24 orbits. The entire system moves with great regularity.
The celestial symphony
Video: Rhythmic and harmonious musical vision of transits of planets in front of their star. A team of NASA researchers and musicians has turned the orbits of the seven worlds TRAPPIST-1 into music.
No other known planetary system has so many resonant worlds.
The computer simulations suggest that the planets should have bumped very quickly after their formation. But the resonance apparently saved them, according to Dan Tamayo, Cornell University Ithaca, New York.
The planets of the TRAPPIST-1 system are therefore in perfect orbital resonances and these harmonious orbits can be translated musically, with notes. TRAPPIST-1b corresponds to the note b, TRAPPIST-1c corresponds to the note c, TRAPPIST-1d corresponds to the note d, etc.
Each planet plays a note in orbit as it passes between us and its star, and a rhythmic beat is heard every time it passes its neighbor.
As each planet resonates with its neighbors, the whole system forms a chain of harmonic resonance.
This is what shows (accelerated) this dazzling and melodious animation where the seven planets waltz in almost perfect synchronism.