massless

[mas-lis]

adjective

Physics.

1. pertaining to an elementary particle having zero rest mass, as a photon.

Other Word Forms

• masslessness noun

Word History and Origins

Origin of massless¹

First recorded in 1875–80; mass + -less

Example Sentences

Such events are capable of generating neutrinos -- tiny, almost massless particles that constantly pass through space and Earth.

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A few have also pursued the axion, a nearly massless particle originally proposed to solve a different problem with the theory of the strong nuclear force.

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New simulations of these events show hot neutrinos -- tiny, essentially massless particles that rarely interact with other matter -- that are created during the collision can be briefly trapped at these interfaces and remain out of equilibrium with the cold cores of the merging stars for 2 to 3 milliseconds.

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But while his classification system is accurate for particles with mass, it produces inaccurate results for massless particles, like photons.

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"Qin and I showed that using topology," Palmerduca said, "we can modify Wigner's classification for massless particles, giving a description of photons that works in all directions at the same time."

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