Tachyon
hypothetical particle with imaginary mass which is hypothesized to always travel faster-than-light
A tachyon () or tachyonic particle is a hypothetical particle that always travels faster than light. Physicists posit that faster-than-light particles cannot exist because they are inconsistent with the known laws of physics. If such particles did exist, they perhaps could be used to send signals faster than light and into the past. According to the theory of relativity, this would violate causality, leading to logical paradoxes such as the grandfather paradox. Tachyons would exhibit the unusual property of increasing in speed as their energy decreases and would require infinite energy to slow to the speed of light. No verifiable experimental evidence has been found to support the existence of such particles.
The term "tachyon" is derived from a 1967 paper by Gerald Feinberg about excitations of a quantum field with imaginary mass. Subsequent work has shown that the excitations are not faster-than-light particles, but particle physicists still discuss "tachyons", e.g., in tachyon condensation, when they are referring to tachyonic fields.
Etymology
The term tachyon comes from the Greek: ταχύς, tachus, meaning swift. The complementary particle types are called luxons (which always move at the speed of light) and bradyons (which always move slower than light); both of these particle types are known to exist.
“Tachyon” enters the record as hypothetical particle with imaginary mass which is hypothesized to always travel faster-than-light. Crown Archives preserves that source wording while asking what Tachyon, hypothetical and particle can confirm, complicate or overturn.
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Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Aug 30, 2026. The linked authority identifier is Q41995. The Library of Congress control number is sh85131853. 1 of 1 selected statements include explicit references; 1 carry qualifiers and 0 use preferred rank. The first chronological checks are 1967.
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This entry incorporates text from “Tachyon” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.