Limits RegistryPUBLIC RECORD
Limits RegistryThe cosmic microwave background — relic light from about 380,000 years after the Big Bang — has a measured blackbody temperature of 2.72548 ± 0.00057 K, from a 2009 recalibration by Dale Fixsen of COBE/FIRAS and WMAP data. COBE's 1990 measurement showed it to be the most perfect blackbody spectrum found in nature, work recognized with the 2006 Nobel Prize in Physics.
The question, scope, and sources behind this Registry record.
The cosmic microwave background — relic light from about 380,000 years after the Big Bang — has a measured blackbody temperature of 2.72548 ± 0.00057 K, from a 2009 recalibration by Dale Fixsen of COBE/FIRAS and WMAP data. COBE's 1990 measurement showed it to be the most perfect blackbody spectrum found in nature, work recognized with the 2006 Nobel Prize in Physics.
The measured present-day temperature of the cosmic microwave background radiation, the universe's pervasive relic radiation field.
Change a parameter to stress-test whether a proposed result is still inside the published specification. This is an audit aid, not a proof checker.
This record has no editable parameters. Read the formal question and assumptions before challenging it.
Current frontiers derived from accepted Claims.
An observed or demonstrated result; no opposing bound is implied.
The frontier is not sacred
Most progress starts with a disagreement that survives contact with evidence. If you can push the known lower bound up or pull the upper bound down, show us the work.
≥ when you have shown that at least this value is achievable.≤ when you have shown that anything above this value is impossible.No vibes. State the value, define the scope, and link the paper, proof, code, or reproduction that lets another person check it. Editors review every challenge before the public record changes.
Challenge this recordAssertions tied to evidence, attribution, and review.
The frontier as it changed over time.
Only accepted Claims matching the current specification contribute to the displayed bounds. Strict inequalities remain open; contradictory Claims require editorial review.
1 accepted Claim, with 1 linked evidence records.
Permanent ID limitsregistry.com/limits/LR-CMB-TEMPERATURE
No active verified bounties are linked to this Limit.
View verified bounty tracker ↗No accepted machine-checked reproductions are recorded for this Limit.
Limits Registry. LR-CMB-TEMPERATURE. Temperature of the cosmic microwave background. 2026.