Astrophysicists Tighten Limits On Light Speed Variations
In 2026 an international team of astrophysicists published a study this month testing whether light speed varies with photon energy by analyzing ultra-high-energy gamma rays from distant bursts. Using observatories including the High-Altitude Water Cherenkov (HAWC) facility, they found no energy-dependent delays, tightening Lorentz-invariance violation limits by up to 100× to around 10^-17. This narrows quantum-gravity parameter space and guides future observatory strategies.
Key Points
- 1Measured gamma-ray arrival times from >100 TeV bursts at redshifts >1 using HAWC and other observatories.
- 2Tightened Lorentz-invariance violation constraints by up to 100×, pushing limits to around 10^-17.
- 3Forces quantum-gravity models to refine parameters and guides future observatory strategies like CTA.
Scoring Rationale
Strong experimental tightening of Lorentz-violation bounds; limited by aggregated reporting and lack of primary-journal citation.
Sources
Public references used for this report.
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