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/daily ·21 SEPT 2026 ·MONDAY ·2 MIN READ ·6 STORIES

Mice with human brains, melting ice, and a blood type nobody knew existed

Human neurons took over most of a mouse cortex; ice loss from 1976 to 2023 lands at 12 trillion tons; and a blood group has been hiding for half a century.

01 / The Day

MONDAY 21 SEPT 2026, ranked

06

Human brain tissue colonises most of a mouse cortex

Researchers transplanted human brain organoid cells into neonatal mice and watched them expand until human-derived neurons represented the majority of activity in the animals' cortices — the largest fraction of human neural tissue in a living rodent brain recorded to date.

  • Human cells integrated functionally, forming synapses with mouse neurons across layers
  • Cortical takeover developed over weeks, not months, accelerating the timeline for chimeric models
  • Ethical review protocols for cognition-capable chimeras are not yet standardised
Why it mattersA mouse whose cortex runs mostly on human neurons is a qualitatively different research tool — and a qualitatively different ethical question — from earlier chimeric models.
01 sciencenews.org↗

Alzheimer's pathology may begin in lymph nodes, not the brain

A new study found amyloid and tau accumulation in cervical lymph nodes in patients with early Alzheimer's disease, appearing before detectable cortical plaques — suggesting the peripheral lymphatic system is not merely a clearance route but a potential origination site for pathological aggregation.

  • Lymph node deposits preceded cortical pathology in the sample, reversing the assumed sequence
  • Cervical lymph nodes drain interstitial fluid from the brain via glymphatic channels
  • If confirmed, early detection could shift from PET scanning brain to biopsy-accessible peripheral tissue
Why it mattersReordering where Alzheimer's pathology starts changes where you look for it early and where you try to stop it.
02 sciencenews.org↗

Earth lost 12 trillion tons of ice between 1976 and 2023

A 47-year satellite record assembled by researchers at Leeds and NASA shows the planet shed 12 trillion metric tons of ice from glaciers, ice sheets, and sea ice — a loss rate that has accelerated decade-on-decade and is now running at roughly 1.2 trillion tons per year.

  • Rate of loss in 2020-2023 is approximately 57% faster than in 1980-1990
  • Greenland and West Antarctica account for the majority of sea-level-relevant mass loss
  • Arctic sea ice loss is the single largest contributor by volume, though it does not raise sea level
Why it mattersA continuous 47-year satellite record settles the trend question with high confidence — the rate is accelerating, and the dataset is now long enough to distinguish signal from multi-year variability.
03 phys.org↗

Sealed gravity experiment opened after 10 years — the constant is still contested

A laboratory gravity measurement sealed in 2016 was finally opened and analysed in 2026, adding a new high-precision value of Newton's gravitational constant G — and the result sits between the two incompatible clusters of prior measurements, prolonging one of physics' most embarrassing long-running discrepancies.

  • G measurements from different labs disagree by more than their stated uncertainties allow
  • The sealed experiment used a torsion pendulum design independent of the two main methodological clusters
  • No resolution: the new value neither confirms nor collapses either prior cluster
Why it mattersThe most fundamental constant in gravitational physics has been measured dozens of times and the values don't agree — after a decade-long blind experiment, they still don't.
04 sciencedaily.com↗

T. rex ran at near-human body temperature, isotopes confirm

Isotopic analysis of T. rex tooth enamel puts the animal's core body temperature at around 38-39°C — close to modern large mammals and well above earlier estimates that assumed partial ectothermy, settling a multi-decade debate over whether non-avian dinosaurs were warm-blooded.

  • Clumped isotope thermometry reads body temperature from carbonate crystallisation patterns in enamel
  • 38-39°C is consistent with large-bodied endothermy, not the intermediate 'mesothermy' hypothesis
  • Data support full endothermy for at least the coelurosaur lineage leading to birds
Why it mattersDirect thermometric evidence from fossil enamel closes the physiological ambiguity that has shaped every metabolic model of large theropod behaviour for thirty years.
05 sciencedaily.com↗

New human blood group discovered after a 50-year search

Scientists identified the molecular basis of a rare blood group antigen first noticed in the 1970s but never characterised — a protein variant on red cell surfaces that explains why a small population lacks antigens recognised by standard typing panels, and why transfusions have failed in those patients.

  • The antigen is encoded by a previously uncharacterised variant of the GCNT2 gene
  • Patients lacking the antigen risk haemolytic reactions from standard matched blood
  • Adds to the 47 officially recognised blood group systems; clinical typing panels will need updating
Why it mattersHalf a century of failed transfusion matches now have a molecular explanation, and the fix — screening for the variant — is straightforward once labs know what to look for.
06 sciencedaily.com↗
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/MON 21 SEPTMice with human brains, melting ice, and a blood type nobody knew existed/SAT 19 SEPTThe One That Got Away/FRI 18 SEPT37,000 agents, a shrinking Mercury, and a pharaoh's secret room/THU 17 SEPTOrigins Revisited/WED 16 SEPTDark Matter Whispers, Roman Launches, and Brains That Age Too Fast/TUE 15 SEPTThe fluid problem falls, probably/MON 14 SEPTDecoupled Oceans and Jurassic Antibiotics/SUN 13 SEPTSignals and Silences/FRI 11 SEPTNew Proof, Old Problem/THU 10 SEPTHottest Month, Earliest High/WED 09 SEPTMachines Prove What Humans Couldn't/TUE 08 SEPTField Notes/MON 07 SEPTFractons, copper chains, and underground fire/SUN 06 SEPTMilliseconds and megayears/SAT 05 SEPTScience/FRI 04 SEPTImmune Reprogramming and Physics Overturned/THU 03 SEPTSeptember Synthesis/WED 02 SEPTWednesday, September 2/TUE 01 SEPTThe gaps get smaller/MON 31 AUGAcceleration Confirmed/SUN 30 AUGDiamond Rain and Resistant Air