explainer Earth
How heavy is the Earth? About 5.97 × 10²⁴ kg, and how we know
Earth's mass is about 5.972 × 10²⁴ kg (13.2 septillion lb). See how scientists calculate it from orbits and G, why G limits precision, and the maths.
Latest from SciQuestEvidence-led science
news Astronomy Evidence status: Peer reviewed · Method paper
New starlight-removal method recovers known planet 51 Eridani b in JWST data
A Nature study's FLIP software recovered the known planet 51 Eridani b in JWST data at 4.3 microns and beat standard processing 2 to…
news Biology Evidence status: Peer reviewed; phylogenetic modelling with imputed traits
Migratory hooved mammals had higher extinction rates, study finds, but fossils drive the result
A PLOS Biology study finds 80% of 51 recently extinct hooved mammals were likely migratory, versus 46% of living ones, but the model result…
Primary sourcesResearch and official data linked in context
Evidence calibratedObservation, interpretation and speculation separated
Corrections welcomeTransparent updates and a direct reporting channel
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Explore by field and evidence
Choose the kind of evidence you want to read. Labels describe the study type, not whether a finding is true.
Space
Planets, moons, stars and black holes, with the mission data behind each number.
news Astronomy Evidence status: Peer reviewed · Method paper
New starlight-removal method recovers known planet 51 Eridani b in JWST data
news Astronomy Evidence status: Peer reviewed · Observational census
Dwarf galaxies keep only about 11% of the oxygen their stars made, Hubble census finds
news Astronomy Evidence status: Peer reviewed · Observational study
White dwarf’s double debris disc may hide two surviving planetary bodies
news Astronomy Evidence status: Peer reviewed · Single galaxy
JWST finds a barred spiral galaxy candidate 1.1 billion years after the Big Bang
news Astronomy Evidence status: Official announcement · Preprint
Rubin finds dwarf-planet candidate 2026 ED138 beyond Pluto; its size is still an estimate
news Astronomy Evidence status: Peer reviewed · Laboratory analysis of one meteorite
Teghaza 001 meteorite formed at least 4.1 billion years ago and samples Mars’s early crust
news Astronomy Evidence status: Peer reviewed · Observations of one system
Two feeding black holes found 4,900 light-years apart in an early galaxy merger
news Astronomy Evidence status: Peer reviewed · Population study of catalogue data
Two families of multi-planet systems tied to their host stars, study finds
No stories of this evidence type in this field yet.
Physics
Gravity, quantum behaviour and fundamental forces, with the calculations shown.
news Physics Evidence status: Preprint, not yet peer reviewed
B⁰ decay to two muons: LHCb reports 3.2-sigma evidence, short of discovery
news Astronomy Evidence status: Peer reviewed · Statistical analysis of two real events
First Hubble constant from gravitational waves and galaxies: 67 km/s/Mpc, with wide error bars
news Chemistry Evidence status: Peer reviewed · Laboratory measurement on a metal surface
Pentagon-heptagon carbon nanoribbon conducts like a metal, in short pieces
explainer Chemistry
How cold is liquid nitrogen? −196 °C (−320 °F, 77 K) and why it stays there
explainer Chemistry
How cold is dry ice? −78.5 °C, why it skips liquid, and safe handling
news Earth Evidence status: Official announcement
Leap seconds end in May 2027 after vote to let UTC drift up to an hour
news Physics Evidence status: Peer reviewed · Lab demonstration
Google’s quantum chip cuts magic-state errors 40-fold, Science paper reports, but most attempts are discarded
news Physics Evidence status: Peer reviewed · Collider measurement
Jet quenching seen in RHIC oxygen collisions, a sign of quark–gluon plasma
No stories of this evidence type in this field yet.
Biology
Genes, evolution and living systems, with study design and sample sizes made clear.
news Biology Evidence status: Peer reviewed; phylogenetic modelling with imputed traits
Migratory hooved mammals had higher extinction rates, study finds, but fossils drive the result
explainer Biology
Why do cats knead? What “making biscuits” means and what the evidence shows
news Anthropology Evidence status: Peer reviewed · Ancient-DNA analysis
Ancient genomes link Celtic and Germanic spread to migrations, but language is inferred
news Biology Evidence status: Peer reviewed · Fossil description plus bone chemistry
Armoured Triassic amphibian may be the first known to live fully at sea
news Biology Evidence status: Peer reviewed · Behavioural laboratory study
Jumping spiders sleep in two stages, one REM-like, behaviour study finds
news Biology Evidence status: Peer reviewed · Laboratory cultures and genome analysis
Lab-grown Asgard archaea closest to eukaryotes are simple inside
news Biology Evidence status: Peer reviewed · Computational model of four connectomes
Three-neuron circuit may set the fly’s walking rhythm, connectome simulations find
explainer Biology
Why do dogs eat grass? What the evidence says about illness, vomiting and instinct
No stories of this evidence type in this field yet.
Health
Medical research read carefully: mouse, cell and human evidence kept distinct.
news Biology Evidence status: Peer reviewed; population biobank analysis; no health outcomes assessed
Average human genome holds about 5 million variants, and a few linked to disease
news Biology Evidence status: Mouse study · Peer reviewed
Hidden drainage route found at the back of the eye in mice, but its glaucoma link is untested
News Biology Evidence status: Peer reviewed · Mouse study
Can Ozempic Slow Aging? Semaglutide Extended Lifespan in Older Female Mice
News Biology Evidence status: Peer reviewed · Human genetic association study
Scientists Identify 36 Risk Genes Linked to OCD and Tic Disorders
News AI Evidence status: Peer reviewed · Cross-sectional study
AI Emotional Support Is Linked to Distress in Young People
News Biology Evidence status: Peer reviewed · Laboratory and genomic study
Tuberculosis May Evolve Drug Resistance While Drying in Air
News Biology Evidence status: Peer reviewed · Cell and tissue imaging study
Self-Blinking Probes Image DNA Near Double-Helix Resolution
News Biology
Doctors Injected Mitochondria From a Woman’s Leg Into Her Eyes
No stories of this evidence type in this field yet.
Astronomy
What telescopes observe, how astronomers measure it and what remains uncertain.
news Astronomy Evidence status: Peer reviewed · Method paper
New starlight-removal method recovers known planet 51 Eridani b in JWST data
news Astronomy Evidence status: Peer reviewed · Observational census
Dwarf galaxies keep only about 11% of the oxygen their stars made, Hubble census finds
news Astronomy Evidence status: Peer reviewed · Statistical analysis of two real events
First Hubble constant from gravitational waves and galaxies: 67 km/s/Mpc, with wide error bars
news Astronomy Evidence status: Peer reviewed · Observational study
White dwarf’s double debris disc may hide two surviving planetary bodies
news Astronomy Evidence status: Peer reviewed · Single galaxy
JWST finds a barred spiral galaxy candidate 1.1 billion years after the Big Bang
news Astronomy Evidence status: Official announcement · Preprint
Rubin finds dwarf-planet candidate 2026 ED138 beyond Pluto; its size is still an estimate
news Astronomy Evidence status: Peer reviewed · Laboratory analysis of one meteorite
Teghaza 001 meteorite formed at least 4.1 billion years ago and samples Mars’s early crust
news Astronomy Evidence status: Peer reviewed · Observations of one system
Two feeding black holes found 4,900 light-years apart in an early galaxy merger
No stories of this evidence type in this field yet.
Selected reading
More from SciQuest
Clear explanations of what scientists found, how they know and what remains uncertain.
news Astronomy Evidence status: Peer reviewed · Observational census
Dwarf galaxies keep only about 11% of the oxygen their stars made, Hubble census finds
A census of 37 nearby dwarf galaxies finds they keep 4% to 25% of the oxygen their stars made, about 11% on average. Where the rest…
news Physics Evidence status: Preprint, not yet peer reviewed
B⁰ decay to two muons: LHCb reports 3.2-sigma evidence, short of discovery
LHCb reports first single-experiment evidence (3.2 sigma, preprint) for the rare B⁰ decay to two muons, matching the Standard Model but short of discovery.
explainer Earth
How deep is the Grand Canyon? Depth, width and age
The Grand Canyon is about 1,524 m (5,000 ft) deep at the South Rim village and up to 1,829 m (6,000 ft) at its deepest, per…
How SciQuest reports
Interesting science is stronger when readers can inspect the evidence.
Our editorial standard requires every substantive story to identify what was observed, how it was measured, what researchers infer and what remains uncertain.
Read our editorial standards- 01Find the primary evidence
Start with the paper, dataset, mission record or official technical source.
- 02Test the central claim
Check the method, numbers, scope, uncertainty and alternative explanations.
- 03Explain without inflating
Make the significance clear while preserving limits and scientific context.
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Essential explainers
Durable answers with the numbers, the method and the caveats in one place.
explainer Biology
Why do cats knead? What “making biscuits” means and what the evidence shows
Cats knead because kittens do it to keep milk flowing, and adults link it to comfort. See what is observed, what is…
explainer Biology
Why do dogs eat grass? What the evidence says about illness, vomiting and instinct
Why do dogs eat grass? A survey of 1,571 dogs and controlled trials show grazing is normal and rarely linked to illness.…
explainer Biology
Why do cats purr? How the sound is made and what it means
Cats purr at about 25 to 30 Hz to signal contact and calm, but also when hungry or hurt. How the larynx…
explainer Biology
How long does a horse live? Typical lifespan, ponies and the oldest horse
Most horses live 25 to 30 years and a few pass 40, yet many die much younger. Ponies vs horses, the 62-year…