Science
Why the speed of light is a fundamental limit
The universe has a maximum signal speed, and light happens to travel at it.
Science
Discoveries, explanations and the workings of the universe.
Science
Why time seems to speed up as we get older
A birthday, a summer, a whole decade: why do stretches of life seem to shrink in the rear-view mirror? The answer depends on when you ask.
Science
Why Bubbles Are Almost Always Spherical
A bubble’s shape is a quiet negotiation between air pressure, gravity and a film trying to use as little surface as possible.
Science
What If Earth Suddenly Stopped Spinning?
The first danger would be everything that kept moving. The long-term world would be stranger still.
Science
How Can a Material Remember Its Original Shape?
Shape-memory metals and plastics recover a programmed form because their internal structure changes predictably when heated or otherwise triggered.
Science
How Do Scientists Know How Old the Earth Is?
The answer comes from radioactive clocks in rocks and meteorites, not from finding one impossibly old patch of ground.
Science
Why Is the Night Sky Dark When the Universe Has So Many Stars?
A simple question about darkness reveals the age and expansion of the cosmos.
Science
Why Does Static Electricity Get Worse in Winter?
The small shock from a door handle begins with charge, fabric and dry indoor air.
Science
Why can a sound send a shiver down your spine?
A swelling chorus, a whispered voice and an ominous scrape can all produce a bodily jolt. Similar sensations can come from different emotional routes.
Science
Glass is a solid. Why do people say it flows?
Its atoms lack a crystal's tidy pattern, and molten glass can certainly move. Neither fact means an ordinary window is slowly sagging downwards.
Science
Why is ice slippery?
The easy answer is “a layer of water”, but the surface under a shoe or skate is thinner, stranger and more changeable than that sounds.