explainer Physics
Gravity on Uranus: how strong is it compared with Earth?
Gravity on Uranus is 8.69 m/s² at the equator, about 0.89 of Earth's, even with 14.5 Earth masses. See NASA's values, the GM/R² maths and what you'd weigh.
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Category: Physics
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.
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 there.
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 is not simply hotter.
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 air. Smoke adds more.
news Chemistry Evidence status: Peer reviewed · Laboratory materials study
Niobium–titanium alloys stay tough at 20 K (−253 °C) in lab tests
Two niobium–titanium alloys showed no ductile-to-brittle transition at 20 K (−253 °C) in Nature lab tests. How twins make new defects, and what's unproven.
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 why Venus is still deadly.
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 made it useful, and its origin.
news Physics Evidence status: Peer reviewed · Laboratory experiment
Thorium nuclear clock runs for a day, but still trails atomic clocks
A thorium-229 nuclear clock in Vienna locked its laser to nuclei for a day. What it achieved, how it compares with atomic clocks, and what it can't do yet.