A fast radio burst at redshift 2, three billion years after the Big Bang.

FRB 20240304B at redshift 2.148 is the most distant fast radio burst observed, occurring 3 billion years after the Big Bang during peak cosmic star formation.

• Why it matters: Understanding FRBs at such high redshifts can reveal properties of ionized gas and magnetic fields over most of cosmic history, filling a gap in knowledge about early universe conditions.
• What they did: Researchers observed the FRB and identified its host galaxy as a low-mass, star-forming galaxy with a clumpy structure, using radio and near-infrared follow-up, at a redshift of 2.148 ± 0.0013.
• The result: The burst's high scattering suggests a population of undetected FRBs, indicating that current surveys may miss many such distant events, impacting our understanding of cosmic plasma environments.