About the CREDO Project

Scientists have dedicated their lives to trying to understand the Universe we live in but one mystery has remained; 95% of the Universe is invisible to us. We call 68% of the missing Universe Dark Energy and 27% Dark Matter. We know these things exist because of a variety of otherwise unexplained phenomena including the manner in which we see galaxies rotating but we have no idea what they are.

The Cosmic Ray Extremely Distributed Observatory (CREDO) Project is testing one of the many theories for what this dark matter could be – super massive particles born in the early Universe. If this theory is correct, we can’t see the super massive particles themselves, but we should be able to detect what is left when these particles come to the end of their lives, or ‘decay’. The very high energy photons predicted to result from this decay are unlike anything scientists have detected so far coming from outer space. This could be because they are very rare or, more likely, that they don’t make it all the way across the Universe to the Earth without being affected by other particles.

From experiments with high energy particles carried out on the Earth we know that the interactions with other particles is likely to result in lots of lower energy photons being produced in a large ‘cascade’. CREDO refers to these cascades as super-preshowers and they have the potential to be widely distributed across both space (an area larger than the Earth) and time (reaching different parts of the Earth at different times).

Figure 1: The creation of particle cascades detectable on the Earth originating from massive particles in the early Universe.

Existing observatories looking for particles from space are highly unlikely to recognise these super-preshower particles for what they are as they cover a tiny fraction of the Earth’s surface. To identify these widely distributed showers we’d need a detector the size of the Earth which is clearly not possible! However, what we can do, with your help, is have lots and lots of little detectors spread out across the Earth’s surface.

CREDO Detector Smartphone Application

If you have a smart phone with a camera you already have the hardware you need to help detect these particles so by downloading the CREDO Detector App here you can become part of the world-wide CREDO detector and join this quest for the unexpected.


Video 1: Messengers from Space – How the CREDO project is using modern technology to engage the public with cutting edge science exploring our Universe.

The app uses your smart phone camera (while your phone is charging and the camera is covered) to look for the bright pixels caused by the impact of a high energy particle on the CCD detector in the camera. A small ‘thumbnail’ centred on this detection along with the time and date it occurred and were your smartphone was is sent to the CREDO servers.

To learn more about how to use the CREDO Detector App watch this quick tutorial…


Video 2: How the CREDO Detector Smartphone Application is operated by you and utilises your smartphone camera.

Private Particle Detective Citizen Science Experiment

Whether you have a smart phone or not there are still many ways you can get involved in CREDO. With a large number of smartphones detecting particle impacts its important to filter through these images to determine the type of particle detected and also to look out for any unexpected detections. Eventually, a lot of this analysis will be carried out by computers but we need to train the computers to do this saving a lot of time. However, they will never be able to highlight the unusual signals – they just don’t ask the enquiring questions that humans do – so there will always be something valuable for CREDO supporters to do!

You can therefore use the Private Particle Detective Experiment here [under development] to start to follow your particle detections (if you also have the CREDO App) through the analysis process.

Figure 2: The flow of particle detections through the CREDO project and the role of the public and scientists in this collaboration.

Dark Universe Welcome Citizen Science Experiment

Having detected particle impacts with the CREDO App and filtered through those detections to group them into categories with Private Particle Detective we now need to determine if a given detection is part of a super pre-shower. So the Dark Universe Welcome experiment takes the confirmed and categorised detections from Private Particle Detective and asks CREDO supporters to look for groups of detections in space and/or time.

Of course computers can also do some of this analysis but they will take much longer to learn how to do it than people – so we need your help to train them. Also, once again, only a human will accurately pick out and question any unusual groupings so CREDO supporters are essential to the project at this stage.

You can therefore use the Dark Universe Welcome Experiment here to see your particle detections (if you also have the CREDO App) in context with other detections and continue the analysis process.

More Information

If you’re interested in the core astro-particle physics and theory behind the CREDO project you can find more about that here.

You can also find the answers to some Frequently Asked Questions here.