Deep-sea Telescope Probes Einstein’s Theory of Relativity

WHO:

Live Science - The detector is Oscillation Research with Cosmics in the Abyss (ORCA), part of the KM3NeT neutrino telescope.

Yahoo - The detector is Oscillation Research with Cosmics in the Abyss (ORCA), part of the KM3NeT neutrino telescope.

Live Science - Alba Domi, a doctoral student who participated in deploying some of ORCA’s first detection units, and Lukas Hennig, a doctoral student in advanced physics at Erlangen-Nürnberg, are quoted in the article.

Yahoo - Alba Domi, a doctoral student who participated in deploying some of ORCA’s first detection units, and Lukas Hennig, a doctoral student in advanced physics at Erlangen-Nürnberg, are quoted in the article.

Live Science - Researchers tested Lorentz invariance, a principle assumed by general relativity and the Standard Model of particle physics.

Yahoo - Researchers tested Lorentz invariance, a principle assumed by general relativity and the Standard Model of particle physics.

WHAT:

Live Science - Researchers reported no evidence that Lorentz invariance is broken; the measured neutrino oscillations matched standard physics.

Yahoo - Researchers reported no evidence that Lorentz invariance is broken; the measured neutrino oscillations matched standard physics.

Live Science - The team used 5,828 neutrinos collected over about 17 months during 2020 and 2021. It set limits competitive with results from Japan’s Super-Kamiokande, which used 12 years of data, and IceCube, which used two years of data from its full array.

Yahoo - The team used 5,828 neutrinos collected over about 17 months during 2020 and 2021. It set limits competitive with results from Japan’s Super-Kamiokande, which used 12 years of data, and IceCube, which used two years of data from its full array.

Live Science - The researchers set the first direct limits on a type of Lorentz-invariance violation that would affect muon and tau neutrinos differently.

Yahoo - The researchers set the first direct limits on a type of Lorentz-invariance violation that would affect muon and tau neutrinos differently.

Live Science - ORCA had six detection units in the analyzed results; 44 units are in the water, and the collaboration plans to activate 108 by 2030.

Yahoo - ORCA had six detection units in the analyzed results; 44 units are in the water, and the collaboration plans to activate 108 by 2030.

WHERE:

Live Science - ORCA is anchored about 1.5 miles (2.4 kilometers) beneath the Mediterranean Sea off Toulon, France.

Yahoo - ORCA is anchored about 1.5 miles (2.4 kilometers) beneath the Mediterranean Sea off Toulon, France.

Live Science - The neutrinos studied traveled upward through Earth; some crossed about 7,900 miles (12,700 kilometers).

Yahoo - The neutrinos studied traveled upward through Earth; some crossed about 7,900 miles (12,700 kilometers).

Live Science - ORCA’s sister detector, ARCA (Astroparticle Research with Cosmics in the Abyss), is off Sicily’s coast.

Yahoo - ORCA’s sister detector, ARCA (Astroparticle Research with Cosmics in the Abyss), is off Sicily’s coast.

WHEN:

Live Science - The study results were published in the Journal of Cosmology and Astroparticle Physics.

Yahoo - The study results were published in the Journal of Cosmology and Astroparticle Physics.

WHY:

Live Science - Testing Lorentz invariance can constrain theories seeking to reconcile general relativity with the Standard Model, which do not mesh in extreme settings such as the early universe.

Yahoo - Testing Lorentz invariance can constrain theories seeking to reconcile general relativity with the Standard Model, which do not mesh in extreme settings such as the early universe.

HOW:

Live Science - Each ORCA detection unit is seabed-anchored and contains 18 glass spheres, each holding 31 light sensors. Sensors detect faint blue light produced when neutrinos collide with particles in water.

Yahoo - Each ORCA detection unit is seabed-anchored and contains 18 glass spheres, each holding 31 light sensors. Sensors detect faint blue light produced when neutrinos collide with particles in water.

Live Science - The team selected upward-traveling particles to reduce atmospheric-particle background; Earth filters out the other particles, while neutrinos pass through.

Yahoo - The team selected upward-traveling particles to reduce atmospheric-particle background; Earth filters out the other particles, while neutrinos pass through.

Live Science - Neutrinos have zero charge, are nearly massless, and come in electron, muon, and tau types. They oscillate among these types, and a Lorentz-invariance violation would alter the oscillations, with stronger effects over longer distances.

Yahoo - Neutrinos have zero charge, are nearly massless, and come in electron, muon, and tau types. They oscillate among these types, and a Lorentz-invariance violation would alter the oscillations, with stronger effects over longer distances.

Live Science - Domi said IceCube’s ice scatters light more than water, while water absorbs light more than ice, affecting how each detector reconstructs neutrino energy and paths.

Yahoo - Domi said IceCube’s ice scatters light more than water, while water absorbs light more than ice, affecting how each detector reconstructs neutrino energy and paths.

(UPDATED November 5, 2026 22:17 UTC)

A deep-sea neutrino detector found no evidence that a cornerstone of physics is broken. ORCA’s measurements matched standard physics, testing neutrinos that traveled upward through Earth. Researchers also set the first direct limits on violations affecting two neutrino types.