Module 6 unit 1

Physics

Over the last 50 years our knowledge about elementary particles and their interactions has advanced tremendously. Actually, a whole ‘zoo’ of new particles has been detected, some of which are extremely short-lived. The development of new particle accelerators operating at much higher energies was a crucial factor in the rapid advances in particle physics. Theoretical physicists have made substantial progress in uncovering the principles governing their interaction. Another breakthrough was the experimental demonstration of the existence of antimatter.

Moreover 20^th century physics has had a tremendous technological impact. The development of the atomic bomb, and as a consequence the increased knowledge of nuclear physics led to developing reactors to produce electric energy.

Giant steps in research in electron optics led to the development of instruments such as high resolution electron microscope, the scanning tunneling microscope, etc. that allow single atoms to be studied and manipulated. A new area of technology was born.

In the 1980s, spectacular advances were made in the production of ceramic materials that exhibit superconductivity at much higher.

Lasers have proved to have innumerable technological applications. These include a host of different measuring instruments such as detectors for air pollution, high-speed photography, new mass storage devices for computers (CD-ROMs), surgical instruments of various kinds, and even methods to trap and cool atoms, to name just a few.

Perhaps the most pervasive scientific innovation in the last 50 years was research on semiconductors.

Microprocessors had an enormous impact on electrical engineering. Their astounding efficiency and small size gave rise to a host of applications in the most diverse fields. Although computer design had started earlier this century, the extremely rapid development of ever faster computers with vastly expanded memory became possible with the advent of transistors integrated in microprocessors. Virtually all of today’s computing and communication devices are based on this technology.

Another development stemming from semiconductor research was the invention of photo-voltaic cells which can convert light into electric energy. They bring the promise that some day much of our energy needs will be supplied directly by the sun without producing significant pollution.

Molecular biology

Biologists had already speculated that the key to understanding how genes can transmit biological information from generation to generation must be sought

in their molecular structure.

Once the structure of DNA was established, the next question was how the cell ‘reads’ the genetic information stored in its DNA. In a remarkably short time, a small group of molecular biologists cracked the so-called ‘genetic code’.

Since this so-called ‘molecular revolution’ in biology, much progress has been made towards understanding the myriad of mechanisms by which a cell’s genome directs the biochemical processes allowing the cell to survive, divide, and fulfill specific functions in multicellular organisms.

This kind of knowledge, which continues to grow steadily, plays an increasingly important role in the development of novel therapies. Clearly, this would not have been possible without the preceding molecular revolution. The new molecular biology has also originated areas such as cell biology and neurobiology.

Genetic engineering techniques rapidly became an indispensable tool for biological and biomedical research. The human genomic DNA sequence will be extremely useful to bio-medical scientists for understanding how the human body functions and how diseases originate. However, the Human Genome Project has also raised strong ethical issues. These include the possible misuse of such knowledge, the protection of individual privacy, intellectual property rights, and the protection of universal access to public information. For this reason, the Human Genome Project is accompanied by studies of the potentially far-reaching social consequences the new genetics may have.

The possible applications of genetic engineering in biotechnology and medicine are only beginning to emerge. Genetically engineered crop plants have been bred which harbour genes resistant to various plant pathogens. There is an increasing number of therapeutic and diagnostic pharmaceutical products which are made by genetically engineered bacteria. Promising advances have been made in somatic gene therapy, where genetic defects are repaired in certain types of cells or tissues.

Earth sciences

The Earth sciences deal with the history of our planet. This kind of knowledge becomes increasingly involved in improving our understanding of the factors controlling the global environment and in developing more effective ways of finding and assessing natural resources, energy, and water. Methods for the prediction of natural events such as Earthquakes, volcanic eruptions, landslides, floods or El Niño have been greatly improved. Furthermore, important insights into the history of the Earth’s climate have been obtained through the analysis of sedimentary records or ice cores from Greenland. Such knowledge will be important to disentangle global change caused by human beings from naturally occurring variations in the global climate system.

Another important development in the Earth sciences took place in the 1950s, when the theory of plate tectonics was empirically confirmed. Although an earlier version of this theory had already been formulated in the beginning of the 20^th century, it was largely ignored because no-one could imagine the kind of forces necessary for pushing continents, or even the giant tectonic plates that supposedly make up the Earth’s crust.

Earth science will continue to play an essential role in diagnosing and addressing some of the most pressing challenges, such as climate change and sustainable resource allocation that the global community faces.