My very favourite summer activity is stargazing and I don’t know if you do share the same feeling about it as I do. If you do, you probably find that the stars are fascinating too. Here beware that I am not talking about the shooting stars we happen to see during a meteor shower. They’re still cool, but they are no stars at all, they are as you may now suspect meteors. Now coming back to the stars, I may assume that even our ancestors liked looking at the stars. Our ancestors would indeed stargaze and by doing so came to all kinds of conclusions about their nature. From being the spirit of their dead ancestors to being used as tools for prediction, stargazing holds somewhat of a spiritual nature. Always to be respected, those giants of the night sky are notably recognized to have guided humans in their escapades.
Sometimes we often forget that our sun is also a star. However, if you’re thinking about stargazing, forget to consider the Sun as your next subject. As a matter of fact, the word “stargazing” is commonly referred to as the act of contemplating the stars in the night sky. At night, the Sun is, fortunately for you, nowhere to be seen. It’s hiding away on the opposite side of Earth, casting the shadow from which we can observe what we call the night sky. Only from its shadow can we observe the other stars. Looking directly at the Sun is strongly discouraged for reasons that can be explained by both its location and its characteristics.
The Sun is very close to us, but this unique element wouldn’t do much to us if it weren’t a yellow dwarf, to begin with. These very features are what provide the Sun with the ability to project huge amounts of heat and sunlight at us. This is the reason why we can’t look directly at the Sun. The Sun is projecting an important amount of radiation in the form of sunlight. Staring at the Sun unprotected is a sure way for you to burn down your retina, which could cause you to become permanently blind. Despite this issue, the Sun in all of its grandeur is a good thing for us and other forms of life. Its proximity provides sufficient heat to allow us to survive, and thrive for that matter.
The heat, as well as the light, comes from radiation produced through nuclear reactions. Its light is so powerful that, when it shines directly at us, it can interfere with the light of all other stars that are much further. This is why you can hardly see any stars during daylight. Even though looking directly at the Sun is a risky endeavour, with adequate protection, we can safely gaze at it, especially when extraordinary phenomena happen like solar eclipses. Solar eclipses happen when the moon comes between Earth and the Sun. The Sun is then blocked by the moon which casts a shadow on Earth. The shadow can, at that moment, block either partially or completely the sunlight causing the annular form we see.
Something very difficult to discern with the naked eye is how different each and every one of the stars is. They can be compared by size, by gas composition, by age and by many other criteria. Yellow dwarfs (e.g. the Sun) are, in terms of heat emitted, slightly warmer than red dwarfs. These two dwarf stars are the most prevalent stars of our galaxy. Eventually, as they burn through their fuel, they can either cool down to become red giants or transform into white dwarfs becoming suddenly much warmer. Other known star types are blue giants, supergiants, brown dwarfs, neutron stars and pulsars. As a general law, the bluer a star is, the warmer it is and reciprocally the redder, the cooler it is.
Now if you start to worry, don’t, our sun is still young and has a lot of fuel left to burn before turning into a red giant. It’s estimated to be merely 4.5 billion years old, yes that’s still young, I promise you. The Sun is a very stable star that is expected to remain this way for the next 5 billion years. At that point, you and I will be long gone. We won’t have the chance, or should I say the misfortune, to see Earth’s annihilation when it’s going to morph into its next phase. We can hope that, by the time we come to this, we as humans will have succeeded in finding new areas to conquer in our galaxy or maybe even the universe.
Let’s now stop lingering on Earth’s gloomy prospect and let’s simply enjoy the Sun’s presence while it lasts. As I mentioned earlier, thanks to sunlight we can prosper. Not only we as humans but we as all living things. The most obvious example of its benefit on Earth is photosynthesis. Animals may use carbon as the primary source of energy, but plants have developed a strategy to extract their energy from sunlight. Through a cellular apparatus called chloroplast, they can absorb light and transform it into energy. On one of its inner membranes, the thylakoid membrane, are located the chlorophyll pigments which are the ones responsible for absorbing light frequency corresponding mostly to blue and red. Green light is reflected causing the typical green colour we see in plants. When in contact with the pigments, the light energy from the sunlight excites electrons from within and sparks a chain reaction that produces energy in the form of ATP and NADPH. The electrons then need to be replenished and this is done through electrolysis of water, meaning that hydrogen and oxygen are split apart. Hydrogen ions are then used as electrons. This last bit is the part responsible for the plant’s oxygen emission.
Although we also know that the plants are famous for absorbing lots of carbon dioxide (CO2). This occurs mostly at night, in the absence of light. Outside of the chloroplast, CO2, with the use of ATP and NADPH, is transformed into sugar chains. Afterward, the sugar chains are transported to the mitochondria, which is the powerhouse of any cells. The process at this point is very similar to what we can observe in our cells. The mitochondria change the sugar to meet the metabolic demand of its host, or it’s stored away. For plants, the storage of sugar is in the form of glucose or starch. In sum, plants through photosynthesis are essential to our survival by providing the required oxygen we so dearly need.
Sunlight does not only benefit us through plants or the heat it produces, it does also through intricate maintenance of the balance in gas compositions. Sunlight is one of the principal sources of energy that triggers naturally occurring chemical reactions. All these chemical reactions happen at a specific rate that allowed formation then but now maintains our atmosphere. If there were too much solar energy, water would sublimate and the atom of its molecule would split apart forming hydrogen and oxygen. Oxygen would eventually burn away and hydrogen would explode. With too little solar energy, there would not be enough water evaporation causing an eventual depletion of oxygen in the air.
Furthermore, the plants and the atmosphere are not the only ones to benefit directly, we do too. Though, we might only come to realize this when it makes itself scarce. Some northern regions may experience extremely long winters where they can go months without seeing the Sun. This can lead people to experience some discomfort. Yet, even places that don’t see such drastic changes in sunlight exposure during winter might feel this way. This mere reduction seems sufficient to induce troubles. The discomforts can sometimes be so severe that they cause the person to be completely unproductive. This reaction is commonly caused by a seasonal affective disorder, which is regularly referred to as winter blues. Turns out that the lack of sunlight exposure leads to dysregulation of our circadian rhythm and a lower release of serotonin and/or melatonin. These changes make us more likely to develop sleeping issues, eating issues, depression and fatigue. The solutions to avoid this are easy; either you spend more time outside boosting sunlight exposure or you buy a luminotherapy lamp. Usually, these changes only are sufficient to resolve the situation, and thus there is no need for medication.
Personally speaking, the Sun is what I would consider the closest thing to a god. This belief is motivated by the fact that the Sun first created us; now it keeps us safe and provides for us, but later it could also very much destroy us all in the snap of a finger. It’s powerful and always there, even if we can’t always see it. But every star in the night sky is as great and powerful as our sun, even though they appear from our perspective to not be any larger than the tip of a needle. So the next time you get the pleasure to stargaze, remember to enjoy the show that they are offering you and admire their inherent beauty and forces.
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