NO MORE DARK MATTER?
For decades, scientists have been trying to find definitive evidence of dark matter and dark energy, to explain some of the weirder behaviours of the universe. But what if dark matter doesn't even exist?
It explains strange observations at the galactic scale, but could there be an easier way to understand the universe? One without Dark Matter?
In a side gallery of a road tunnel about 1,500 m under Italy's Gran Sasso mountain, physicists are working with a huge detector. The machine is designed to capture the mysterious dark matter, which, according to cosmology, could exist anywhere, in any (maybe every) galaxy. The location under the mountain is ideal for the task, because the rock above the lab protects the detector against interrupting cosmic radiation, but does not halt the dark particles, which only very rarely react with visible matter.
The detector contains 3.5 tonnes of pure, liquid xenon. Scientists hope that a dark particle will collide with the nucleus of a xenon atom, causing it to move and emit light that can be recorded. The detector is extremely sensitive: the machine records as much data in one single day as previous generation detectors could collect in a year. But when the first results were published in May 2017, they were discouraging: the detector had not identified one single dark matter particle.
The physicists in Italy are not the only ones searching for the dark component of the universe. For decades, astronomers have been observing close and remote galaxies, hoping to reveal the existence of dark particles. And since 2010, the LHC accelerator of the CERN research facility in Geneva has been colliding protons at
speeds close to that of light, trying to produce dark matter. But both in the galaxies of the universe and in the underground accelerator, results remain... indeterminate.
Much has been learned, but cosmology, as a science may soon have to make a tough decision. Astronomers need the "darkness". Galaxies are rotating so fast that their outermost stars would be flung in all directions, i f not considerable, i nvisible matter supplemented the mass of the galaxies’ visible matter, keeping the stars in their orbits by means of gravity. And mysterious, repulsive, dark energy is necessary to explain why the expansion of the universe is accelerating.
But as nobody has yet managed to prove the existence of the darkness, new theories emerge. The secrets of the universe may have to be explained in a different way.
DARK MATTER FILLS THEORETICAL HOLE
The concepts of dark matter and dark energy were invented and introduced into cosmology to save Einstein’s general relativity theory.
The complex theoretical work from 1915 describes how the matter of space created the modern universe along with gravity. The theory embraces developments all the way back from the Big Bang, which started the expansion of the universe, to the present. It explains the formation of the first stars and dwarf galaxies and describes how individual galaxies have grown over time via collisions and subsequently collected into galaxy clusters on the surfaces of huge bubbles of empty space.