One day. One Earth. Connected through cosmic particles.

On 19 November 2026, students and scientists around the world will carry out their own cosmic-ray measurements as part of a coordinated global hands-on physics activity — the International Cosmic Day.

We warmly welcome everyone interested in exploring the fascinating world of cosmic particles.

What is the International Cosmic Day?
The International Cosmic Day is a worldwide one-day event in which students and scientists investigate cosmic rays through local, hands-on measurements and data analysis and share there findings.
It connects classrooms and research institutions across the globe in a coordinated scientific experience focused on astroparticle physics.

Join ICD2026

If you want to participate, please register under Registration. In case you have any questions, write us an e-mail at icd@desy.de.

 

The International Cosmic Day is organized by DESY, IPPOG and many national networks and partners.