explainer Space
How far can the human eye see? From the horizon to 2.5 million light-years
On flat ground the horizon is about 4.7 km away, but on a dark night you can see the Andromeda Galaxy 2.5 million light-years off. Here is why.
Latest from SciQuestEvidence-led science
explainer Physics
Gravity on Neptune: how strong is it compared with Earth?
Gravity on Neptune averages 11.27 m/s², about 1.15 times Earth's, despite 17 Earth masses. See NASA values, the maths and what you would weigh…
explainer Physics
How hot is fire? Flame temperatures by colour, fuel and type
How hot is fire? Most flames burn at about 900–1,400 °C. See candle, wood fire, gas and Bunsen flame temperatures, and why blue fire…
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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.
explainer Physics
Gravity on Neptune: how strong is it compared with Earth?
news Astronomy Evidence status: Peer reviewed · Calculated colours from existing spectra and models
White dwarf colours: most look white, a few would glow green or pink
explainer Astronomy
How many moons does Venus have? Zero, and Mercury has none either
explainer Space
Gravity on Venus: how strong is it compared with Earth?
explainer Astronomy
How long does it take to get to each planet? Real mission times
news Astronomy Evidence status: Peer reviewed · Observational study of one planet
JWST maps WASP-17b’s atmosphere: evening edge runs about 650 K hotter
explainer Astronomy
How long does it take to get to Mars? Mission times and the math
Explainer Space
Gravity on other planets: surface gravity of planets and major moons
No stories of this evidence type in this field yet.
Physics
Gravity, quantum behaviour and fundamental forces, with the calculations shown.
explainer Physics
Gravity on Neptune: how strong is it compared with Earth?
explainer Physics
How hot is fire? Flame temperatures by colour, fuel and type
explainer Earth
Why is the sky orange? Red, yellow and pink skies explained
news Chemistry Evidence status: Peer reviewed · Laboratory materials study
Niobium–titanium alloys stay tough at 20 K (−253 °C) in lab tests
explainer Space
Gravity on Venus: how strong is it compared with Earth?
explainer Physics
How far is a click? Klick meaning, conversions and origin
news Physics Evidence status: Peer reviewed · Laboratory experiment
Thorium nuclear clock runs for a day, but still trails atomic clocks
explainer Physics
How does an atomic clock work? Caesium, accuracy and GPS
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 · Meta-analysis of published fossil records
Fossil pollen ties plant life’s two biggest turnovers to extreme ancient warmth
news Biology Evidence status: Peer reviewed · Single fossil specimen
Jurassic swimming mammal relative hints suckling anatomy evolved early
news Biology Evidence status: Peer reviewed · Genomics study (embryos and tissues)
Octopus and squid DNA forms flexible loops linked to brain development
news Biology Evidence status: Peer reviewed; observational study of pet dogs
Why big dogs die younger: DNA study finds faster epigenetic ageing
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 · Genome-wide association study
What Shapes Personality? Study Finds 1,260 DNA Variants—but Genes Aren’t Destiny
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
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: 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
News Biology
Two Injections Improved Memory in Alzheimer’s-Model Mice—Not Humans
No stories of this evidence type in this field yet.
Earth
Climate, geology and oceans, traced back to measurements and official records.
explainer Earth
Why is the sky orange? Red, yellow and pink skies explained
news Earth Evidence status: Peer reviewed · Mineral-proxy study
Crystals hint Earth’s mantle was oxidizing before the Great Oxidation Event
news Biology Evidence status: Peer reviewed · Meta-analysis of published fossil records
Fossil pollen ties plant life’s two biggest turnovers to extreme ancient warmth
news Earth Evidence status: Peer reviewed · Modelling study
Great Unconformity: a vanished cliff may explain the Grand Canyon’s missing billion years
Explainer History
The Most Ancient Civilization In The World
Explainer Earth
Why Is Water Blue In Color?
Explainer Earth
Why Is The Dead Sea So Salty?
Explainer Earth
What If The Earth’s Core Stops Spinning?
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More from SciQuest
Clear explanations of what scientists found, how they know and what remains uncertain.
explainer Earth
Why is the sky orange? Red, yellow and pink skies explained
Why is the sky orange, red, yellow or pink? Air scatters blue light about 6 times more than red, and sunset light crosses ~38 times more…
news Astronomy Evidence status: Peer reviewed · Calculated colours from existing spectra and models
White dwarf colours: most look white, a few would glow green or pink
Nearby white dwarfs look white on average, Warwick astronomers calculate, but about 1 in 30 would look yellow or pink, and one known star would look…
news Earth Evidence status: Peer reviewed · Mineral-proxy study
Crystals hint Earth’s mantle was oxidizing before the Great Oxidation Event
Sulfur in apatite sealed in zircons up to 3.42 billion years old suggests the mantle under early arcs grew more oxidized long before oxygen stayed in…
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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
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- 02Test the central claim
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Essential explainers
Durable answers with the numbers, the method and the caveats in one place.
explainer Astronomy
How many moons does Venus have? Zero, and Mercury has none either
How many moons does Venus have? None, and Mercury has none either. See NASA's moon counts for every planet and why the…
explainer Space
Gravity on Venus: how strong is it compared with Earth?
Gravity on Venus is 8.87 m/s², about 90% of Earth's. See the NASA values, the GM/R² calculation, what you would weigh, and…
explainer Astronomy
How long does it take to get to each planet? Real mission times
How long does it take to get to each planet? From 94 days to Venus to 12 years for Neptune: real NASA…
explainer Physics
How far is a click? Klick meaning, conversions and origin
A click (klick) is military slang for one kilometre: 1,000 m, about 0.62 miles. See conversions, why 1 km Army map grids…