JWST Spots a Never-before-seen Cosmic Signal Defying Lab Replication

WHO:

ScienceAlert - Astronomers led by David Neufeld of Johns Hopkins University detected a previously unseen rotational-light signal from the trihydrogen cation, H₃⁺.

Yahoo Tech - Astronomers led by David Neufeld of Johns Hopkins University detected the signal using the James Webb Space Telescope (JWST).

ScienceAlert - Astrophysicists Fu-Shih Pan and Takeshi Oka of the University of Chicago calculated that H₃⁺ could emit faint rotational light.

Yahoo Tech - H₃⁺ is described as a foundation of almost all gas-phase interstellar chemistry and as “the molecule that made the Universe.”

WHAT:

ScienceAlert - The team identified 26 distinct spectral lines associated with H₃⁺’s forbidden rotational transitions; the strongest had a statistical significance of 72 sigma.

Yahoo Tech - The signal appeared in JWST observations of Herbig-Haro 168 (HH 168), and the team later found the same signature in archival observations of Herbig-Haro 211 (HH 211).

ScienceAlert - In HH 168, H₃⁺ emission closely tracked ordinary molecular hydrogen (H₂) emission.

Yahoo Tech - One shock-wave model reproduced H₂ emission but underestimated H₃⁺ emission by a factor of five or six. Another came closer to the H₃⁺ signal but used conditions beyond the model’s validated range.

ScienceAlert - The research was accepted for publication in *The Astrophysical Journal Letters* and is available on arXiv.

WHERE:

ScienceAlert - The detected light came from gas thousands of light-years away, in the Herbig-Haro 168 region.

Yahoo Tech - Herbig-Haro objects form when newborn stars’ jets collide with surrounding molecular clouds.

WHEN:

ScienceAlert - Pan and Oka’s prediction of faint rotational emission was made in 1986; the signal remained unconfirmed for four decades.

Yahoo Tech - The predicted H₃⁺ rotational emission had not previously been detected, including in laboratory experiments.

WHY:

ScienceAlert - The signal was considered “forbidden” because the transitions are extraordinarily weak under the usual rules governing molecular radiation, not because they violate physical laws.

Yahoo Tech - Detecting H₃⁺ emission may help scientists study shock waves from newborn stars and the chemistry that builds complex molecules from simple elements.

HOW:

ScienceAlert - H₃⁺ consists of three hydrogen nuclei sharing two electrons in an equilateral triangle; centrifugal forces during rotation slightly distort its symmetry, creating a tiny dipole moment that allows faint radiation.

Yahoo Tech - JWST’s infrared observations can penetrate obscuring dust more effectively than visible light, enabling observations of star-forming regions.

(UPDATED November 13, 2026 02:05 UTC)

Astronomers detected H₃⁺’s long-predicted rotational light using the James Webb Space Telescope. The faint signal came from newborn stars’ shock waves, revealing 26 distinct spectral lines. The discovery could help scientists investigate shock waves and the chemistry that builds complex molecules.