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Talking rocks
Disclaimer: no Geodude was damaged during this study. For those who don’t know, Earth is a magnet. A really big one, so we are surrounded by a massive magnetic field that works as a protector shield against radiation from the Sun and other weird outter space things. As a magnet, it has two poles. But do you know that what we call North Pole is actually the magnetic South Pole and viceversa? If you follow a compass you would think that it is pointing to the North. But compasses are aligned with the field lines (Faraday’s idea, who was a great scientist without scientific formation, which is cool), and the field lines are a map that tell us how to go from the North to the South of a magnetic field, apart of many other things (look at the figure). So poles are reversed. And rocks have been secretly telling us that it has been reversing for so long.
In the Mid-Atlantic Ridge, two tectonic plates are slowly separating. As a result, melted rock under the lithosphere, called magma, reaches the surface and solidifies under the ocean, creating new lithosphere (Icelandic vulcanism). Magnetic things are magnetic because the spin of their electrons are coherently aligned, contributing to create this magnetism. But in some rocks, spins are usually randomly oriented, neutralizing between themselves and making the total contribution to create magnetism zero. However, under some temperature conditions, these spins can be forced to align with an external magnetic field (Paramagnetism and Curie’s Law). Casually, when this rocks are created, they reach that temperature, so their spins aligne with the external magnetic field at that moment (the Earth’s one). When the conditions disappear the magnetization remains in time (Ferromagnetism and Remanent Magnetism). Nowadays, we can take those rocks and determine when they were created and where was pointing the external magnetic field at that moment. (Another figure). By the way, this is the explanation of Geodude evolutive line becoming electric type in the new Pokemon games.
Figure: Seafloor spreading and and magnetic reversal. https://divediscover.whoi.edu/mid-ocean-ridges/magnetics-polarity/
This is tectonic plates movement demonstrating itself. And rocks use magnetism to explain us about it, like if they were an open book of Earth’s history. In the future, it may occur again, maybe sooner than later, looking at the periodic behaviour of these reversals. Is our telecommuncation based world prepared for this?
Header figure: Paramagnetic and ferromagnetic geodudes
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γγγβ γ*γγγγγΒ°γγγγπ° γ°·γγ πͺ
.γγγβ’γΒ° β γβ’ β
βββββ βββββ ββββ. -
Music After All
What’s the sound? Sound is defined for four different attributes: loudness, duration, pitch and timbre. Of course, when we paint a sound in our mind, we think about a sinusoidal wave. A wave have some properties, like the amplitude and the frequency. When we move to the music world, the amplitude is translated as volume (loudness), and the frequency as the musical note. We know that the spectrum of frequency is kind of infinite, and even the humans can only hear a part of that infinite (20 Hz – 20000 Hz), this part keeps being an infinite continuous. A musician can divide the continuous of frequencies in notes, as C, Dβ or Gβ― (pitch). For example, when the particles we were talking about are moving 440 times in a second, we have an A. That’s the definition of note.
To simplify the conception of music, we defined 12 different notes, going from the lowest to the highest, and every time we play 12 notes we find the same note again, but higher. We use the same name because the frequency we find after 12 notes is a multiple of the frequency of our first note. If we play a note that vibrates 130 times in a second, we have a C, but we keep having a C if the note vibrates 260 or 520 times every second (these multiples are called harmonics). And yes, we have 11 more notes between the first C and the second, and 11 between the second and the third. If we play the C in a guitar, it will be different than the C we play in the piano, because of the combination of harmonics of C that they emit (timbre, and is also the main reason of why do you recognise people for their voices).
When we play different sounds at the same time, we are talking about harmony. And when the sounds evolve through the temporal dimension, that’s the melody. When two different melodies are played independently at the same, like if they were dancing with each other, we are mixing harmony and melody. That’s the counterpoint.
With these concepts we can listen what the universe is telling us, and they are also the basics of one of the most amazing things that humans do to decorate time. Cause science, is music after all.
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γγγβ γ*γγγγγΒ°γγγγπ° γ°·γγ πͺ
.γγγβ’γΒ° β γβ’ β
βββββ βββββ ββββ. -
Don’t trust your eyes
Have you ever been sailing at dusk and suddenly saw an old creepy sailboat in the horizon giving you any kind of signals? Probably it would be trying to give you a message from other people who you could never find, cause they would have died three centuries ago. Iβm talking about the legendary ghost ship, The Flying Dutchman. Years before Pirates of the Caribbean and One Piece popularized the story of Willem van der Decken’s ship, the sailors were already talking about a flying boat imbued in a spectral light.
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The Flying Dutchman, Pirates of the Caribbean
The responsible of this kind of story is the physical phenomenon of the refraction: when a wave that is moving in a medium with some conditions makes it to a different medium, the wave experiences a change of its velocity of propagation. In this case, the medium is the air, and the other medium would be an air with different density.
Well, probably not all of us have the experience of seeing a ghost ship but we all have heard about mirages in the desert. In the desert you can remember your name β«, and moreover it’s very hot. That makes the air located just over the sand get hotter than the rest of the air. This temperature gradient implies a density gradient, so it also implies a gradient of the refraction index. This gradient curves the rays of the light, so we can see in the ground the reflection of objects located far away, despite they seem to be closer. That’s the optical illusion of the oasis, the inferior mirage. A less fancy example would be the false water that we see on a long road on a hot day.
In the case of the boat, the air touching the sea is the colder one, so it’s a superior mirage. In this case, if the gradient is strong enough to make the curvature of the light bigger than the curvature of the Earth, we could even see islands floating in the sky. This may sound as a fairytale, in fact, it’s called Fata Morgana in reference to the fairy of the Arthurian Legend.
But I want to talk about another optical phenomenon: the green flash. Seconds after dusk, or seconds before the dawn, if the sky is clean enough, you can see a green ray coming from the horizon, just from over the Sun. When the light of the Sun is traveling around the atmosphere, it moves slower on the inferior air, denser than the air of the top layers. Due to this, the light follows a curved path. The light of higher frequencies, as the blue and green colors, are more curved than the rest of the light, so the green remains in the sky while the red is gone.
Jules Verne said that in these few seconds you can see βa green which no artist could ever obtain on his palette, a green of which neither the varied tints of vegetation nor the shades of the most limpid sea could ever produce the like! If there is a green in Paradise, it cannot be but of this shade, which most surely is the true green of Hopeβ.
Fata Morgana
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A star has been born
I don’t really like the concept of God, or the existence of anything ruling the world over the rest of the people. But there always has been this creature deciding what happens on the Earth, who lives, who dies, the amount of clothes that you are wearing, or even that day that you took a decaf in case you weren’t able to sleep at night. I’m talking about a colorful plasma ball that we all know as Sun, or, in Pumbaβs words βa ball of gas burning billions of miles awayβ. We are in a great debt with the Sun, and to pay for it we should know who was responsible for lighting it up.
When the Universe was born, atoms, photons and other kinds of particles started to run away in an homogeneous way. Fortunately, some of those particles found each other on the way, creating anomalies on the density, like clumps on the cocoa. Through gravity interaction, these grumps attract other particles increasing their size and evolving into big, like hundreds of lightyears diameter, and beautiful clouds of gas and cosmic dust, known as nebulae. Nebulae were rotating and getting hotter and hotter, until a gravitational collapse occurred. This led to some conditions of density, temperature and pressure that allowed the appearance of nuclear fusion reactions, making atoms fuse to each other. These reactions emit radiation, which has associated a pressure directed towards the outside of the star; the pressure balances the gravitational force of the star, which is trying to compress the star itself. This is the so-called βhydrostatic equilibriumβ, the first condition for a star to exist. For a better understanding, a star is trying to explode but its own weight keeps it away from doing it. By this moment, the cosmic night started to be illuminated by the stars, like in Van Gogh’s painting.
La noche estrellada, Van Gogh
But our Sun is not that old. Eternities after their creation, the stars died in explosions filling the Universe with stardust. As the goldsmith does in Final Fantasy, the ancient stars used nuclear reactions to forge new elements (C, O, Si, Fe…) by fusioning simpler ones (H, He, Li, Be) , so this stardust is the same that is composing our planet and us by this time, but this is another story. Part of the stardust created new nebulae, and someday in this cycle, approximately 4600 millions of years ago, the Sun was born.
“Pillars of Creation” taken by Hubble Space Telescope
header image: from NASA.
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γγγβ γ*γγγγγΒ°γγγγπ° γ°·γγ πͺ
.γγγβ’γΒ° β γβ’ β
βββββ βββββ ββββ.
