Martina Paul at the Festpielhaus in Bregenz. The date of Day of Photonics on October 21st was chosen to commemorate when the General Conference of Weights and Measures adopted the value of 299,792.458 km/s for the speed of light on 21 October 1983.

Martina Paul at the Festpielhaus in Bregenz. The date of Day of Photonics on October 21st was chosen to commemorate when the General Conference of Weights and Measures adopted the value of 299,792.458 km/s for the speed of light on 21 October 1983.