The traditional terms „race“ and „racial group (type)“, referring to a division of humankind possessing a combination of physical traits that characterize it as a distinet human type, are no longer usable. Even in the past, the concept of race was far from unambiguous: Darwin gave examples of' classifications of' humans that ranged from two to sixty-three different varieties. The modern view of the concept of race recognizes that mass migrations as well as mixed marriages have occurred so frequently during the last several centuries that the so-called races are for the most part no longer definably distinet. Two approaches are now used to discuss human physical variety. One is clinal: a cline is a gradient of morphological or physiological change in a group of related organisms, usually along a line of geographical or environmental transition. For example, if one maps the distribution (presence or absence) of epicanthus or of the degree of skin pigmentation in the world's populations, one realizes that physical traits are not covariant. The second approach is to recognize that a breeding population has a noticeable frequency of' certain genes in comparison or contrast with other populations.
This year‘s Nobel Prize in Physics was awarded to three astrophysicists, Jim Peebles, Michel Mayor and Didier Queloz. Peebles was awarded half of the prize for cosmology and Mayor and Queloz were awarded a quarter each for the discovery of the first exoplanet orbiting a Sun-like star 51 Pegasi. Their discovery was reported almost 25 years ago and started a new era of exoplanetary research. This article presents the steps leading to the discovery of planet 51 Pegasi b and the following efforts to detect and characterise exoplanets. The future of the exoplanetary research field is also discussed in this article. and Petr Kabáth.
Polární záře jsou konečným důsledkem řetězce událostí souvisících se sluneční aktivitou. Nabité částice se od Slunce šíří jako součást slunečního větru meziplanetárním prostorem. Malá část z nich je zachycena magnetosférami planet a některé z nich magnetosférou naší Země. Zejména elektrony pak interagují s horními vrstvami atmosféry a excitované atomy či molekuly kyslíku a dusíku způsobují při deexcitaci překrásné nebeské divadlo - polární záři. V článku jsou vysvětleny makroskopické a mikroskopické mechanismy vzniku polárních září včetně historie jejich výzkumu. Stručně jsou shrnuty výsledky expedice Aurora 2002 pořádané katedrou fyziky FEL ČVUT a sdružením Aldebaran Group for Astrophysics. Diskutovány jsou naše zkušenosti s fotografováním a pozorováním polárních září., Jakub Rozehnal, Petr Kulhánek., and Obsahuje bibliografii
A mobile exhibition, German Science Train, which is organized by the Max Planck Society as part of the Year of Science 2009, takes the public on a research voyage! The idea is to show different aspects of science with an eye to the future. In 12 converted train cars, visitors can dive into different subjects: from cosmology to particle physics, nanotechnology and brain research to applied and industrial research in production, agriculture, energy, environment and mobility. The exhibition is making stops throughout Germany until December. and Luděk Svoboda.