Help us looking for dark matter with just your phone!

  • Tomáš Lanča
  • 28.05.2021
The international project CREDO (Cosmic-Ray Extremely Distributed Observatory) has been running since the end of August 2016, and the scientists from the Institude of physics in Opava also take part in its implementation. The project is focused on the detection of cosmic rays and the search for a mysterious „hidden substance“ (or also „dark matter“) in the universe. Unraveling its mystery could be within reach with the help of widest public. All you need is one app on your smartphone that can detect the volatile particles that accompany the hidden substance.
Despite the fact that astronomers have been researching the universe for centuries, more than 95% of the composition of the universe is unknown to us. it is assumed that 68% of the universe is made up of hidden energy and the remaining 27% is hidden matter. It is known that these components do exist in the universe, due to a number of otherwise inexplicable phenomena, such as the contradictory observations of galaxy rotations. This was pointed out in 1932 by the Dutch astronomer Jan Oort (1900-1992) and in 1933 by the Swiss-American astronomer with Czech roots, Fritz Zwicky (1898-1974). Unlike hidden energy, hidden matter is not distributed evenly in space because, due to its gravity, it clumps together (as it is with visible matter) and thus gravitationally attracts the visible matter as well. Some recent research shows that hidden matter could also affect the electromagnetic radiation present in space - the polarization of the microwave background. But other than that no one really knows what the nature or form of these hidden components are. There are only assumptions that can be difficult to confirm or refute without better observation technology.

But the answers are hidden in cosmic rays. Every second, our Earth is bombarded with billions of charged microscopic particles, including those from unknown hidden matter. Some of these particles can have extremely high energy, sometimes even billion-times higher than the a particle generated by CERN - the largest particle accelerator on Earth. These particles are called cosmic rays, and the more energy these particles have, the rarer they are. The cosmic particle with the highest energy is very difficult to detect: in a whole century, only a single one per square kilometer is detected. In order to increase the probability of such detection, it is necessary to build a larger detector. Is it possible to build one with the size of a continent, the whole Earth, or even bigger? People from the CREDO project want to achieve just such an ambitious idea.

But the answers are hidden in cosmic rays. Every second, our Earth is bombarded with billions of charged microscopic particles, including those from unknown hidden matter. Some of these particles can have extremely high energy, sometimes even billion-times higher than the a particle generated by CERN - the largest particle accelerator on Earth. These particles are called cosmic rays, and the more energy these particles have, the rarer they are. The cosmic particle with the highest energy is very difficult to detect: in a whole century, only a single one per square kilometer is detected. In order to increase the probability of such detection, it is necessary to build a larger detector. Is it possible to build one with the size of a continent, the whole Earth, or even bigger? People from the CREDO project want to achieve just such an ambitious idea.

How does it work? If you have a smartphone with a camera, you already have the hardware needed to detect these particles. All you have to do is download the CREDO detector application and start identifying those specific particles in the normal radiation around us. The application uses the camera of your smartphone (for example, while the phone is charging on the table and the camera is covered) to search for bright pixels caused by the impact of a high-energy particle on the CCD detector in the camera. A small "thumbnail" of such detection is sent to the CREDO servers, along with the time and date when your device was involved in the project. In retrospect, you can check if your phone just picked up that specific particle from space.

Even if you don't have a smartphone, you'll be able to join the experiment. The CREDO experiment could, with some exaggeration, be called a kind of "planet-wide civic scientific patrol". For a large number of particle-detecting smartphones, it is important to filter these images to determine the type of particles detected and also to monitor for any unexpected detections. Much of this analysis will eventually be done on computers, but as many computers as possible will be needed to save a lot of processing time. For these purposes, the Private Particle Detective program is already under development, which performs further analyzes on detections recorded by smartphone users. You can see how it all works in a short educational video.

Scientists believe to make great progress in solving many cosmological issuess, while foretelling that since the times of the similarly tuned SETI @ Home project, which has improved distributed computing through volunteer users around the world and also was helping to search for extraterrestrial civilizations, CREDO is the most interesting and advanced project involving the global public in scientific research.  Even if the coveted volatile "photon" from the original supermassive particle fails to be detected in the end, the project will not run in vain. All other unusual particles captured from space on a mobile phone camera can help in finding answers to other cosmological questions, so (not only) for CREDO fans, the result of research will always be something new and valuable!
A blue image of the measured annular distribution of Hidden Matter around the center of a cluster of galaxies was inserted over an image from the Hubble Space Telescope. CL0024+17. Kredit: NASA, ESA, M.J. Jee a H. Ford (Johns Hopkins University).
The aim of the CREDO project is to involve smartphone users in the detection of specific particles - photons created by the decay of supermassive particles in the early universe. It is these detections that could provide answers to the questions surroundi