Text 1. Solar energy

 

Life is impossible without the Sun’s light. Energy received as solar radiation drives all life and meteorological processes on the Earth. The Sun provides the external energy supporting the life activities within all ecosystems. Practically all the fuels that we have to use now (gas, oil, coal) are stored forms of energy received from the Sun as electromagnetic radiation millions of years ago.

The energy flux reaching the outer atmosphere of the Earth is called the solar constant. At present, solar constant is about 1367 W/m². The Earth’s planetary albedo is defined as the fraction of the total incident solar reflected by a planet back to space. At present albedo of the Earth is equal to 30% (where 20% is the reflection of clouds and airborne particles of the atmosphere, 5% is the reflection of the Earth’s surface).

Clouds, dust, water vapour and gases of the atmosphere absorb about half the solar radiation that might otherwise reach the Earth. Eventually, 150W/m² is the flux of the solar radiation that reaches the Earth’s surface.

The Sun is a thermonuclear reactor. Energy is released in the form of electromagnetic waves of a wide range. They extend from X-rays of very short wavelength to radio waves of very long wavelength. But almost all the Sun’s radiation falls within the ultraviolet, visible, and infrared radiation bands. Approximately half of solar energy occurs in the visible part of the solar spectrum between 400nm and 700nm, about 25% – in the ultraviolet band, and the remaining solar energy occurs at near infrared wavelength from 700nm to 4,000nm.

The near-ultraviolet radiation from the Sun produces the ozone layer, which in turn protects the Earth from such radiation. Almost all ultraviolet radiation is absorbed by the ozone layer and oxygen. This is vitally important for living things as ultraviolet is extremely harmful to most forms of life.

The atmosphere is almost perfectly transparent to incoming radiation of the visible band. The Earth reradiates this energy as infrared (heat) waves. Water vapor, carbon dioxide (CO₂), nitrous oxide (N₂O), ozone (O₃), and some other gases absorb infrared wavelength, much of them gets reradiated back towards the Earth. The atmosphere therefore behaves like glass in a greenhouse. This phenomenon is termed the “greenhouse effect”. If the Earth had no atmosphere, its average surface temperature would be –18⁰С instead of comfortable +15⁰С found today. Thus the greenhouse effect resulted in the warming of atmosphere system and of surface temperature on the Earth.

The first law of thermodynamics states that when energy of one form disappears, an equivalent amount of energy appears in some other form. It means, that light energy can be neither created nor destroyed as it passes through the atmosphere. However, it may be transformed into equivalent amount of another type of energy, energy of motion (kinetic energy), or heat.

According to the second law of thermodynamics the efficiency of any energy transformation is never “perfect”: when energy changes from one form to another, some of the energy is lost to the system as “useless” heat.

The laws of thermodynamics hold for all energy transformations, including those involving the biochemical energy of life. According to these laws the earth-atmosphere system balances absorption of short-wave solar radiation by emission of long-wave infrared (heat) radiation to space.

I. Read and translate the words:

ozone, spectrum, solar, toxic, lethal, mineral, hydrogen, oxygen, thermonuclear, ultraviolet, thermodynamics.

II. Form adjectives from the following nouns with the use of the suffix -less. Translate the words:

change, end, doubt, rest, care, harm, shame, regard, water, weight, use, odor, colour, breath.

III.  Find Russian equivalents:

 solar radiation; received as; outer atmosphere; as electromagnetic radiation; ultraviolet radiation; incoming radiation; extremely harmful; is termed; according to; balances absorption.

 согласно; ультрафиолетовое излучение; солнечное излучение; входящее излучение; внешняя атмосфера; регулирует поглощение; в качестве электромагнитного излучения; чрезвычайно вредный; называется; получаемое как.

IV. Answer the questions:

•      What is the source of energy supporting all life and meteorological processes?

•     How is albedo defined?

•      What part of the Sun’s radiation falls in the visible band of the solar spectrum?

•      What happens to the ultraviolet portion of solar radiation when it passes through the atmosphere?

•      What radiation is the atmosphere more transparent to: the visible sunlight or heat (infrared) radiation?

•     What would the average Earth’s surface temperature be without greenhouse effect?

•      Why is the first law of thermodynamics called the law of energy conservation?

•     What is useless heat?

•     How is radiation balance maintained?

V.  Translate into English:

источники энергии; длина волны; водяной пар; формы жизни; отраженное излучение; потоки энергии; диапазон излучения; круговорот вещества.

VI. Translate the given phrases into Russian and make up sentences with them:

life under certain conditions; pass through the atmosphere; on the top of the atmosphere; transformed into thermal radiation; back into space; by clouds and airborne particles; in the visible part of spectrum; from X-rays to radio waves; according to the law; average surface temperature; absorbed by the ozone layer; transparent to incoming radiation; without sunlight.

VII. Give the spectrum of electromagnetic radiation from short wavelength to long wavelength:

cosmic rays; visible waves; far infrared; gamma rays; radio waves; near ultraviolet (UV); TV waves; X rays; far ultraviolet; microwaves; near infrared.

VIII. Translate the nouns formed by word-composition. Use them in a sentence:

greenhouse, airborn, wavelength, ultraviolet, biosphere, thermodynamics, infrared, ultraviolet, microwaves.

IX.  Read and translate the text:

Solar power is often mentioned as the logical and proper alternative to exhaustible sources of energy. And indeed, the amount of radiant energy that strikes the Earth’s surface is far more than is needed. For the generation of electricity, however, there are serious problems to be solved. To collect and concentrate the energy by reflectors and converters of present efficiency is the major difficulty. The other obvious problems are unfavourable weather conditions, energy storage requirements, and the use of the shadowed space. The desert is a logical place to locate solar devices because of open space, isolation, and the frequency of sunny days, but transmission costs for electrical power to urban centers would be excessive. We can hope to develop converters from heat energy to electrical energy and perhaps exploit superconductivity of metals at a very low temperature to reduce transmission costs, but it is clear that there remain many technological problems in this area.