I am an astrophysicist, and my research focuses on the formation and evolution of galaxies. In particular, I develop analytical and numerical models that allow us to study the physical processes that drive galaxy formation and evolution as a function of cosmic time, in a cosmological context.
Last December, newspapers around the World have given space on their pages to the Chinese moon landing attempt, which unfortunately failed shortly afterwards, when the rover suddenly failed. Even if the attempt ended in failure, it remains a significant symbol of how much China is investing in scientific research and technological innovation. Moreover, in 2020 China has planned to build the Chinese Space Station.
PLATO 2.0 (PLAnetary Transits and Oscillations of stars) has recently been selected for European Space Agency’s (ESA) M3 launch opportunity (2022/24). It is a medium class mission within the framework of the ESA Cosmic Vision 2015-2025 program. PLATO 2.0 will discover many potentially habitable planets.
In a diagram published in 1970 showing the distribution of pulsars in the Galaxy, there are about fifty points. In the same year, an article on the optical identification of X sources discusses a handful of them: all those known at the time. If we compare the state of astronomy forty years ago with the current situation, we are especially struck by the tremendous amount of data that we have been accumulating at an increasingly frantic pace.
Gamma-ray bursts (GRBs) are the most powerful explosions so far observed in the universe since the big bang. They are a frequent phenomenon (approximately an explosion per day) and can be observed in all sky directions (isotropic). Gamma-ray bursts can not be seen from Earth because gamma and X rays are absorbed by the atmosphere.
Ichnology is the branch of paleontology that deals with the study of footprints left by animal organisms. Ichnology thus studies the width, length and shapes of footprints, stride (the distance between each one), the depth, possible asymmetries and more, in order to establish the size of the the animals, their characteristic forms and habits. The positioning of the footprints as well contains important information regarding the movement and pace. Just think of a horse's footprints and the difference between a trot and a gallop.
Was there ever really a beginning of everything? Including time? One can hardly imagine a more existential question in the spirit of each human being. Philosophies and religions have approached this issue incessantly since man left traces of his own existence. We find the same questions being asked by the Greek philosophers just as well as by the religious leaders of the Middle Ages. To the question "What was God doing before creating the world?» St.Augustine replied «The question is meaningless because God, together with the world, also created time! ».
The standard model of cosmology, as opposed to the standard model of elementary particles, does not enjoy great generality: it is based on the simplest class of solutions among the solutions of Einstein's general relativity equations, that describe gravity and link matter distribution to the geometric properties of space-time. In particular, the basic assumption is that matter is approximated to a perfectly homogeneous fluid.
Look up at the stars and ask yourself: what scares me more ? To be alone in the Universe, or to know that there is someone else up there? An age-old question, as valid for you and me as it was for Giordano Bruno when he wrote about an “infinity of worlds” before being burnt at the stake in 1600. But fifty years ago to the day, a letter to Nature ended the passive, look-up-and-ponder attitude by proposing a scientific, experimental approach. We don’t have an answer yet (or you and I would know), but in the process we have come up with quite a tale to tell.
This paper investigates the tensions within the Society of Jesus, especially at the Roman College, at the time of Galileo and how they were resolved or not in a spirit of accommodation which was maturing at that time and which has entered into the Jesuit bloodstream. Jesuits at the Roman College confirmed Galileo’s earth-shaking observations, reported in his Sidereus Nuncius. Aristotle’s physics was crumbling. Would Aristotelian philosophy, which was at the service of theology, also collapse?