e-Astro: O e-learning aplicado ao ensino da astronomia: Planetas telúricos

A investigação em didáctica das ciências tem mostrado que a generalidade dos alunos manifesta cada vez menos interesse para aprender ciências. No entanto, o incremento da importância de temas científicos no nosso dia-a-dia, exige dos indivíduos um conhecimento científico cada vez mais aprofundado. O estudo da Astronomia permite abordar e interligar os conteúdos de tisica mais facilmente, tomando possível a aproximação do conhecimento científico ao conhecimento do quotidiano, mostrando a estreita ligação entre a Física, a Sociedade e a Tecnologia. O processo de ensino-aprendizagem encontra-se em mudança devido à integração das T.I.C. Através da internet e tirando partido da multimédia é possível desenvolver uma formação científica adequada que contribua para o despertar da curiosidade e do interesse dos alunos pela Ciência. Tendo em conta os pressupostos anteriores pretende-se, com este estudo, desenvolver uma plataforma de e-learning e recursos multimédia que satisfaçam estes requisitos. ABSTRACT; The investigation in didactics of sciences has been showing that the generality of students show less and less interest to learn sciences. However, the increment of the importance of scientific themes in our day-to-day life, demands from the individuals an increasingly deeper scientific knowledge. The study of Astronomy allows to approach and to interconnect physics subjects more easily, making possible the approach of scientific knowledge to the knowledge of everyday life, showing the narrow connection among Physics, Society and Technology. The teaching-learning process is in change duet the integration of the I.C.T. Through the internet and taking advantage of multimedia it is possible to develop an appropriate scientific formation that contributes to the awakening of curiosity and of the student's interest for Science. Having in mind the previous presuppositions is intended, with this study, to develop an e-learning platform and multimedia resources that satisfy these requirements.

The locations of recent supernovae near the Sun from modelling 60Fe transport

The signature of 60Fe in deep-sea crusts indicates that one or more supernovae exploded in the solar neighbourhood about 2.2 million years ago1–4. Recent isotopic analysis is consistent with a core-collapse or electron-capture supernova that occurred 60 to 130 parsecs from the Sun5. Moreover, peculiarities in the cosmic ray spectrum point to a nearby supernova about two million years ago6. The Local Bubble of hot, diffuse plasma, in which the Solar System is embedded, originated from 14 to 20 supernovae within a moving group, whose surviving members are now in the Scorpius– Centaurus stellar association7,8. Here we report calculations of the most probable trajectories and masses of the supernova progenitors, and hence their explosion times and sites. The 60Fe signal arises from two supernovae at distances between 90 and 100 parsecs. The closest occurred 2.3 million years ago at present-day galactic coordinates l = 327°, b = 11°, and the second-closest exploded about 1.5 million years ago at l = 343°, b = 25°, with masses of 9.2 and 8.8 times the solar mass, respectively. The remaining supernovae, which formed the Local Bubble, contribute to a smaller extent because they happened at larger distances and longer ago (60Fe has a half- life of 2.6 million years9,10). There are uncertainties relating to the nucleosynthesis yields and the loss of 60Fe during transport, but they do not influence the relative distribution of 60Fe in the crust layers, and therefore our model reproduces the measured relative abundances very well.