One of the biggest mysteries in science – dark energy – doesn't actually exist, according to researchers looking to solve the riddle of how the Universe is expanding. For the past 100 years, physicists have generally assumed that the cosmos is growing equally in all directions. They employed the concept of dark energy as a placeholder to explain unknown physics they couldn't understand, but the contentious theory has always had its problems. Now a team of physicists and astronomers at the University of Canterbury in Christchurch, New Zealand are challenging the status quo, using improved analysis of supernovae light curves to show that the Universe is expanding in a more varied, "lumpier" way.

The missing ingredient for cooking up stars in the same way you might steam your Christmas pudding has been spotted for the first time by astronomers. Much like a pressure cooker has a weight on top of its lid to keep the pressure in and get your festive dessert dense, moist and ready to eat, merging galaxies may need magnetic fields to create the ideal conditions for star formation. Until now, however, the existence of such a force had only been theorised rather than observed. An international team of researchers led by Imperial College astrophysicist Dr David Clements found evidence of magnetic fields associated with a disc of gas and dust a few hundred light-years across deep inside a system of two merging galaxies known as Arp220.