Recent studies have revealed that the bending of light around massive galaxies is significantly smaller relative to theoretical expectations. This finding, the so-called lensing is low problem, has been interpreted as a breakdown of our cosmological model. Now, a team of scientists has found that the mismatch between theory and observations is actually caused by […]
Imagine a Universe that started with a huge explosion setting the beginning of space and time to the point that such concepts have no meaning until then. Imagine a Universe that, after an inflationary phase (extremely fast expansion), kept expanding and forming stars and galaxies distributed in a sponge-like structure dominated by walls and filaments […]
“The last star will slowly cool and fade away. With its passing, the universe will become once more a void, without light or life or meaning.” So warned the physicist Brian Cox in the recent BBC series Universe. The fading of that last star will only be the beginning of an infinitely long, dark epoch […]
Nearly a century after dark matter was first proposed to explain the motion of galaxy clusters, physicists still have no idea what it’s made of. Researchers around the world have built dozens of detectors in hopes of discovering dark matter. As a graduate student, I helped design and operate one of these detectors, aptly named […]
Astrophysics • Cosmology • DIPC Astrophysics • DIPC Computational Cosmology
The Javalambre-Photometric Local Universe Survey, J-PLUS, is an unprecedented photometric sky survey of 8500 deg 2 visible from Javalambre (Aragón, Spain), using a set of 12 broad, intermediate and narrow-band filters. The J-PLUS photometric system is well suited to study the properties of nearby galaxies (z < 0.015). However, there are a few redshift windows […]
No matter how elegant your theory is, experimental data will have the last word. Observations of the retrograde motion of the planets were fundamental to the Copernican revolution, in which the sun replaced Earth at the centre of the solar system. And the unusual orbit of Mercury provided a spectacular confirmation of the theory of […]
We started this series discussing the basic ingredients of the Universe: events, spacetime, causality. In the last chapter , we introduced massive objects (and thus, matter), which appear as a generalization of the so-called photon box. As it moves, any object traces a path. Physicists call it worldline . We established that a massive object […]
In the previous chapter of this series, we went over the subjective, relative separation of the network of events known as Spacetime into space and time. The speed of light played a major role in the discussion. In particular, we divided Spacetime into three regions (with respect to a particular event) defined by the existence […]
The division of past and future In Part 1 of this series, we presented the empirical fact that under extreme circumstances, a certain observer’s past can be in another observer’s future. To explain this, we introduced the network of cause and consequence relations as the fixed background structure of reality. This network constitutes Spacetime. Causality […]
I remember very well my physics professor during my first year at university. She stressed the importance of having clear intuitions of what physical terms mean before any mathematics was invoked. ‘Imagine someone drops an 100-gram apple 1 metre above your head’, she would say; ‘the pain you feel is the equivalent of a joule […]