DATE2025.11.26 #Press Releases
Capturing the Universe on a Second Timescale
- Mass Detection of Flash Events from Artificial Satellites and Space Debris -
Summary
When we look up at the night sky, the stars appear to twinkle uniformly. In reality, however, the universe is full of transient and dynamic phenomena, such as the explosive death of stars (supernovae). The field that studies this “time-varying universe” is known as time-domain astronomy, and it has become an active area of research worldwide.
A research team consisting of members from Tohoku University, the University of Tokyo, RIKEN, NTT, and Tokyo University of Science has conducted the world’s most sensitive “wide-field video observations” of the night sky using the wide-field camera Tomo-e Gozen at Kiso Observatory. As a result, the team detected more than 1,500 flash events lasting only 0.5 seconds. Most of these flashes were caused by reflections of sunlight from artificial satellites and space debris. The study revealed that such flashes occur as frequently as 10 million times per day across the whole sky. This finding highlights the significant impact that artificial objects have on searches for second-scale transient phenomena in visible light—an important step for future transient surveys. Moreover, the data also offer a new method for identifying space debris that has been difficult to track, enabling the study of their numbers and properties.
The results of this research were published in The Astrophysical Journal on November 26, 2025.
Figure：Image of a flash event detected from the video data.
The five panels displayed horizontally represent a time sequence at 0.5-second intervals, with the flash appearing only in the central frame (red box). Each panel covers a field of view of approximately 0.03 degrees.
Video: A video of a detected flash event. The field of view is approximately 0.098° (vertical) × 0.16° (horizontal).
Links
Tohoku University, RIKEN, NTT, Tokyo University of Science.
Journals
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Journal name Title of paper Observation of proton tunneling correlated with phonons and electrons in Pd