Eclipse experiment may explain why sun is so hot

The total eclipse of the sun, on 11 August 1999, will help scientists to understand a question that has been puzzling them for 50 years: why the sun's outer atmosphere — the corona - is so hot.

United Kingdom scientists have been investigating the corona's heat since the 1940s by using large ground-based telescopes and a spacecraft but the exact reason remains elusive. It is known that magnetic fields are involved but whether the heating process is by magnetic waves or tiny explosions called nano flares is the subject of much debate.

The experiment relies on the latest electronic digital cameras linked to a specially adapted computer. The cameras are similar to those in video camcorders but are faster and more sensitive. The computer will "grab" and process data from the camera at ultra-high rates (50 frames per second). The set-up, known as the solar eclipse coro­nal imaging system (Sects), will be the fastest digital astronomical camera in the world.

Professor Ken Phillips from Rutherford Appleton Laboratory, Oxfordshire, southern England, and Peter Gallagher from Queen's University Belfast, Northern Ireland, will take the equipment to the Black Sea coast in Bulgaria, where the total eclipse will last two minutes. They will be joined there by collaborators from Poland.

The experiment will investigate what causes the sun's atmosphere to be so hot — two million degrees Celsius - far hotter than the sun's surface, which comparatively Is only 6,000 degrees. Rapid changes in the sun's magnetic field are thought to be the source of the heating and the Secis instrument should be able to detect these oscilla­tions for the first time. It is only during an eclipse that the sun's outer atmosphere, the corona, is visible from earth; usually, the brightness of the sun obscures it.

Professor Phillips, who has just returned from testing the equipment in Poland, explained: "We only have two minutes of total eclipse to gather all the data so it is crucial that there are no hitches. We are going to the Black Sea coast because the chances of clear skies are very good but if we miss this one the next total eclipse in the world will be in Africa in 2001."

The research is funded by the Particle Physics and Astronomy Research Council PPARC), the UK's national astronomy funding body, as well as the Leverhuime Trust.

PPARC is government funded and provides researchers from UK universities with .access to world-class facilities and funds the UK membership of international bodies such as the European Laboratory for Particle Physics, CERN, and the European Space agency. More information about the eclipse and the Sects experiment is available on be national eclipse website (at: www.eclipse.org.uk).

Man and his environment

The problem of man and his interaction with the environment has now become one of the difficult problems for many sciences not because it is fashionable but because of its great significance for the whole of mankind. We see at present the signs of ecological imbalance, which may cause a crisis if due measures ² are not taken.

The air we breathe, the earth we live on and its rivers and seas are becoming polluted ³ with ever more dangerous, materials—by-products ⁴ of man's activities. Man depends for his life on what the biosphere provides: water, oxygen, food, etc. But the biosphere is strongly affected by all sorts of human activities. For example, man creates new compounds, new substances, pure chemical elements which are unknown to biosphere. They do not belong to the natural cycle of matter. They weaken the capacity of natural processes for self-regulation. Though not changing biolog­ically, we change the environment in which we live. The Soviet great scientist Vladimir Vernadsky was the first in the world to realise the necessity for quite a new approach to the biosphere as early as the midforties.⁶

The increasing noise level is a special problem nowadays, We need silence as much as we need fresh air and unpolluted water. Noise does not only do physical damage to the hearer but can weaken his energy and break down his nerves.

Transport is a major source of environmental pollution. Every car consumes many tons of air. Its exhaust gases contain poisonous carbon dioxide which makes difficult the emission of the earth's heat into space. Many cities now are too noisy to live in. Los Angeles in the USA and Osaka in Japan are known to be the air pollution champions among major industrial cities.

Pollutants are not only harmful to health but to buildings as well. Our cities are dying physically. In most city centres some of the oldest and finest buildings are falling in pieces.⁷ On one hand, the foundations are being shaken by all the heavy traffic and, on the other hand, the bricks are being eaten away by fumes from the traffic. It is a slow process but it is going on even though you can't see it.

One more aspect of the problem is water pollution. Sea- and river-going ships often pollute sea and river water

with various oil products. At a rough estimate,⁸ no less than five million tons of oil are discharged into seas and oceans each year and one ton of oil can spread over about twelve square kilometres of the water surface as a fine film which prevents air-water oxygen exchange. One litre of oil makes one million litres of fresh water unfit for drinking. We must stop the contamination ⁹ of our water­ways which comes from so many sources: chemical waste from factories, thermal waste from power stations, domes­tic waste from cities and towns and so on.

Notes

1. environment — окружающая среда

2. due measures — должные меры

3. to pollute — загрязнять; pollution -— загрязнение! pollutants — загрязнители

4. by-products — побочные продукты

5. man depends for his life on — в жизни человек зависит от

6. as early as the midforties —- еще в середине сороковых годов

7. are falling in pieces — разрушаются

8. at a rough estimate — по грубым подсчетам

9. contamination pollution