RBFLOAT, which stands for Radio Brightest Flash Of All Time, is the brightest fast radio burst ever detected by astronomers. It was identified using the CHIME radio telescope and its Outrigger stations in Canada and was traced to galaxy NGC 4141, located approximately 130 million light-years away in the constellation Ursa Major. Despite lasting only a fraction of a second, RBFLOAT briefly outshone every other radio source in its entire host galaxy, making it an unprecedented astronomical event.

What is a fast radio burst?

A fast radio burst is a brief but intense flash of radio waves originating from deep space. These bursts typically last only milliseconds but release as much energy as the sun produces in an entire day. First discovered in 2007, fast radio bursts remain one of the most mysterious phenomena in astrophysics. Some FRBs repeat, suggesting they come from persistent sources like magnetars, while others like RBFLOAT appear to be one-time events with no repeat bursts detected despite years of monitoring.

How was RBFLOAT detected and located?

RBFLOAT was detected by the CHIME radio telescope, a large stationary interferometer in British Columbia, Canada, designed specifically to survey fast radio bursts. The precise location was determined using the CHIME Outrigger project, which added smaller telescope stations at sites across North America to create a very long baseline interferometer. By comparing the arrival times of the radio signal at different stations, astronomers triangulated the burst's origin to galaxy NGC 4141 with unprecedented precision, allowing follow-up observations with other telescopes.

Why is RBFLOAT significant for science?

RBFLOAT challenges existing theories about fast radio bursts in several ways. Its extreme brightness suggests an unusually powerful source mechanism that current models struggle to explain. The absence of any repeat bursts in over six years of monitoring data contradicts theories that all FRBs eventually repeat. Follow-up observations with the James Webb Space Telescope detected a faint infrared signal at the same location, potentially revealing the environment that produced this extraordinary burst and providing clues about the underlying physics.

What telescope found RBFLOAT?

RBFLOAT was discovered by the Canadian Hydrogen Intensity Mapping Experiment, known as CHIME, a revolutionary radio telescope located at the Dominion Radio Astrophysical Observatory in British Columbia, Canada. CHIME uses four large half-cylinder reflectors to survey a wide area of sky simultaneously, making it ideal for catching unpredictable fast radio bursts. The Outrigger project extended CHIME's capabilities by adding smaller telescope stations across North America, enabling precise source localization that previously required much larger radio telescope arrays.

ScienceMarch 2026

RBFLOAT: Brightest Fast Radio Burst Ever Detected

Published: March 19, 2026

Astronomers detected the brightest fast radio burst ever, nicknamed RBFLOAT, and traced it to galaxy NGC 4141 using CHIME Outrigger telescopes, challenging FRB repeat theories.

Earth.com | Artist rendition of RBFLOAT from NGC 4141

Simulated Radio Burst Pulse

Discovery Profile

Distance

130M light-years

Galaxy NGC 4141, Ursa Major constellation

Duration

< 1 second

A mere fraction of a second

Repeat Bursts

None

No repeats found in 6+ years of data

Designation

FRB 20250316A

RBFLOAT (Radio Brightest Flash Of All Time)

What Happened

In March 2026, the CHIME radio telescope in British Columbia, Canada, recorded an extraordinary signal from deep space. This fast radio burst, later designated FRB 20250316A and nicknamed RBFLOAT, shattered the brightness record for any FRB ever detected.

Despite lasting only a fraction of a second, RBFLOAT briefly outshone every other radio source in its entire host galaxy, NGC 4141, a spiral galaxy located approximately 130 million light-years from Earth in the constellation Ursa Major. This extraordinary brightness stunned astronomers and immediately triggered follow-up observations with multiple telescopes.

The precise location of RBFLOAT was pinpointed thanks to the CHIME Outrigger project, a network of smaller telescope stations positioned at sites across North America. By comparing the signal arrival times at different stations, researchers localized the burst's origin with unprecedented precision.

McGill University | CHIME Outrigger telescope array

Why This Matters

RBFLOAT poses a serious challenge to existing fast radio burst theories. Its extreme brightness suggests an unusually powerful source mechanism that current models struggle to fully explain. Popular theories hold that FRBs are emitted by magnetars, but RBFLOAT released far more energy than a typical magnetar burst could produce.

Particularly notable is the complete absence of repeat bursts. In over six years of monitoring data, CHIME recorded no additional signals from the same location. This contradicts the hypothesis that all FRBs eventually repeat, and suggests that multiple distinct types of FRB sources may exist.

Follow-up observations with the James Webb Space Telescope detected a faint infrared signal at the same location, potentially providing clues about the environment and physical mechanisms that produced this extraordinary burst. Scientists continue to analyze the data to better understand the nature of RBFLOAT.

ScienceDaily | CHIME FRB Outriggers localizing RBFLOAT

Key Findings

Record brightness

RBFLOAT briefly outshone every radio source in the entire galaxy NGC 4141

Origin identified

Traced to galaxy NGC 4141, 130 million light-years away, via CHIME Outrigger

No repeats

No repeat bursts found in over 6 years of monitoring data

Infrared signal

JWST detected a faint infrared signal at the same location

Theory challenge

Contradicts the hypothesis that all FRBs eventually repeat

Explore more cosmic discoveries: Vera Rubin Observatory 2026 and NASA ESCAPADE Mars mission.

▸ RBFLOAT released as much energy in under 1 second as the Sun produces in an entire day — equivalent to billions of billions of light bulbs switching on simultaneously.

▸ At 130 million light-years away, this burst occurred when dinosaurs still roamed the Earth.

References

Frequently Asked Questions

The most common questions about RBFLOAT and fast radio bursts.

By David Park · Deep Tech & Quantum Correspondent

Published: March 19, 2026 · Updated: March 25, 2026

science·fast radio burst · RBFLOAT · CHIME telescope · NGC 4141