The Sun: the Source of Life


The Sun is a powerful force. Yet, some people may take it for granted without fully comprehending the extent of its magnitude. In summer, we always complain of the Sun’s heat, sometimes wishing it would just disappear! However, can we live or even imagine life without a Sun?

Energy from the Sun’s core, in the form of sunlight, is responsible for supporting almost all life on Earth via photosynthesis, as well as regulating Earth’s temperature and weather.

Today’s industrial world is supported by the energy sources of oil, coal and natural gas, all of which are essentially derived from solar energy; these non-renewable energy sources will all disappear one day. Until that day arrives, fossil fuels mining, drilling, processing, production and usage will continue to have a tremendously devastating environmental impact on Earth and life on it.

Free and renewable, solar energy, on the other hand, will always represent a viable solution to the world’s energy problems. Its minimal, if non-existent, environmental impact constitutes one of its primary selling points in supplanting fossil fuels as our main source of energy.

The Sun is the ultimate source of wind energy. As it heats the Earth’s surface, the air above it warms and rises upwards into the atmosphere. Land usually heats up faster than do the seas; they also cool faster. As warmer air rises, it creates a partial vacuum and the cooler heavier air flows in to fill the void. This Sun-induced flow of air over the Earth's surface is wind. Eventually all the wind's energy is converted into diffused heat from the friction with land masses and the atmosphere.

The Sun is the engine of the water cycle, which is how water moves through the atmosphere and the Earth’s surface. During the process of the water cycle, the Sun provides thermal energy to the Earth’s surface water, which evaporates because of it and ends up in the atmosphere as water vapor.

When it cools and rises, it forms clouds, which eventually condense into water droplets. Depending on the temperature of the atmosphere and other conditions, water precipitates as rain, sleet hail or snow; which in turn, ends up in the oceans, seas, lakes, rivers and as groundwater.

In addition, sunlight is the fuel that maintains plant life; plants need the Sun because sunlight is made up of electromagnetic radiation, which penetrates the Earth’s atmosphere and is considered the key ingredient in the process of photosynthesis. This process uses raw materials such as carbon dioxide, water, and solar energy to produce oxygen and carbohydrates.

Sunlight is the battery-charger of life; a daily dose of sunlight will do wonders to your feeling of well-being, and to your health in general. It is nearly impossible to get adequate amounts of vitamin D from your diet; sunlight exposure is the only reliable way to generate vitamin D. Moreover, sunlight helps the body produce nutrients to maintain bone mass and lessen the risk of osteoporosis.

Besides maintaining health, the Sun also regulates our biological clocks, helping us maintain a regular schedule of sleep and wakefulness that we need to function at our best.

What if the Sun disappeared?

If the Sun did not exist, there would be no Earth or life to begin with. If, for some obscure reason, the Sun one day disappeared, the whole Earth would fall into complete darkness; something that would damage human beings both physically and mentally.

Without sunlight there would be no green plants because the photosynthesis process would stop. Not only would plants disappear, but the animals that depend on green plants for food would also disappear; so will carnivores as they will not find meat to eat, and naturally, omnivores, including Man.

Temperatures normally drop between sunrise and sunset; if the Sun vanishes, it will simply keep dropping at the same rate, or an even higher rate as the water freezes out of the atmosphere and Earth loses its cloud cover. Most humans, as well as most life on the planet, would have frozen to death.

Fortunately, we still have billions of years until the Sun disappears. Still, just in case, astronomers are on a mission to find an Earth-like planet; but, can they find a Sun-like star?


*The original article was published in the PSC Newsletter, Safe Summer (Summer 2012) issue.

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SCIplanet is a bilingual edutainment science magazine published by the Bibliotheca Alexandrina Planetarium Science Center and developed by the Cultural Outreach Publications Unit ...
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