The Alpha Magnetic Spectrometer was installed on the International Space Station in 2011 with the goal of measuring antimatter in cosmic rays as well as search for dark matter.
Dark matter is a hypothetical construct built from existing theories but never before been directly observed. It is called “dark” because it is invisible to the electromagnetic spectrum and so cannot be seen. Instead, only its strong gravitational effects can be felt. Scientists became interested in dark matter when they realized that the universe had to contain far more matter than had been observed.
The Spectrometer’s data is giving hope that dark matter can be observed and better understood. By measuring the length of time it takes cosmic rays to reach the Spectrometer, the masses of positrons can be determined, which in turn can help determine whether or not excess mass appears to be present. The excess mass would presumably be composed of dark matter.
Two independent teams, one from Germany and one from China, have independently reviewed the evidence and came to similar conclusions, namely that the presence of dark matter is the best explanation of the results the Spectrometer received.
Scientists estimate that 25% of the universe is composed of dark matter. Understanding more about dark matter likely holds the key to understanding the future of the universe, because it holds the key to understanding gravitational effects in the universe. Three possible scenarios for the future are possible: the universe could expand too fast and dissipate, the universe could reach a point where gravity causes it to contract and collapse on itself, or reach an equilibrium where the universe simply stops expanding. Until more is known about dark matter, it is impossible to know for sure what fate will befall the universe.