What is the solar constant?

The solar constant is the measure of the force of the square meter of sunlight directly affecting the perpendicular plane of the space above the Earth's atmosphere and is considered a uniform value of 1,370 watts per square meter. However, this changes dramatically on the surface of the Earth, as sunlight must pass through various layers of atmosphere depending on the latitude and level of the sea and atmospheric conditions. The solar constant is therefore largely a reference number from which the actual solar light values ​​are to be established and is helpful in such areas as the location of solar fields for the production of energy or solar furnaces and in the weather and agricultural calculations. As a pure value above the atmosphere boundaries, the solar constant also differs by 3% depending on the point at which the Earth is in its orbit the sun, because the orbit is slightly elliptical.

While solar radiation values ​​for the solar constant usually focus on visible light, values ​​are calculationEm all received solar electromagnetic radiation. This includes infrared light, X -rays and radio waves that are transmitted by the sun, albeit high -frequency waves such as X -rays, are less than 1% of the total emitted energy. Where sunlight has reached the Earth's surface, this radiation is referred to as insulation and has an optimal level of about 1,000 watts per square meter. Practical values ​​caused by higher latitudes, different altitudes, overcast sky and other causes of indirect light will drop this value to 250 watts per square meter, reducing the true level of solar energy received by the Earth in space by more than five.

The solar constant is an important value to know the development of satellite and spacecraft. This is due to the fact that these systems often have solar panels to generate Powehm and that they can be damaged by some sunlight if they are not properly protected. Research of solar cycles for the sun, including the calculation of sunstorms and sun spots activity, is also dependent on the solar constant and its level of density of flow or the relative amount of solar energy transmitted to a square meter. It is known that the sun itself has a slight variability of radiation levels during 11 -year cycles ± 0.2%. This, along with a 10% increase in the solar constant every 10,000,000,000 years, can have a dramatic impact on the earthly climate in regional areas, such as the sea or on a global basis over time.

Exploration of space with crew to places like the Earth's Moon or Mars planet must also take into account the solar constant for these regions. The solar energy is largely similar to the pure value for Earth when it is on the surface of the moon, due to the same relative distance from the Sun and the fact that the moon does not have an atmosphere. Mars, howeverat the atmosphere. In space or on barren planets and asteroids, the solar constant is the primary indicator of how much energy is available to process rocks into useful materials such as oxygen and hydrogen, or to generate electricity to maintain artificial environmental systems and communication equipment.