The light from a star is not constant, it varies as the layers of hot material move back and forth, clump and disperse. Most of these vibrations are visible, detectable, and well understood. But some bizarre new vibration is happening in stars, for which we have no clear path to an explanation.
We understand cosmology by building models that we can trace back through time, but nothing about these models limits them to the past. As the universe expands, faster and faster pushed by dark energy, when does that acceleration outstrip gravity? And when do the last stars form?
In a strange, half-lost, piece of work Roger Penrose draws four figures dropping their lines into the depths of a black hole, and in doing so finds a new and hugely influential way to steal energy away from the heart of a spinning singularity.
In 1972 astronomers witnessed the first full galaxy collision, not by looking up at the sky but by peering at a small screen in a very large box. The methods and implications are enshrined in modern astrophysics, but it is the results themselves that still truly amaze, stunning simple images of galaxies, playfully strewn and joyfully picked apart. A full exploration of a galaxy of a scale not matched before or since.
We all teach, in some form, every single day. For many academics that means a class full of students eager to learn. And yet we are so very rarely taught to teach. Here we introduce one simple morsel that can improve our way of explaining something immensely: deciding what you want to say, and then saying it.