The physics of observers

We explore non-constructive proofs and what happens if you try and avoid them.

Can a mathematical object be said to exist if you can't construct it?

Physics is all about observation. But how much can we actually see with the naked eye?

The limits to what we can observe are not only a matter of science, but also of politics and economics.

Observing the smallest building blocks of matter doesn't involve seeing in the ordinary sense.

Physics is all about observation, but how much can we actually see?

There are limits to how much you can simultaneously squeeze the quantum fuzziness of an electron's position and momentum

We take the real numbers for granted, but what are they really?

Physicists believe that around 82% of all the matter in the Universe is invisible dark matter. But if it's invisible how do they know it's there?

Cosmology has an ambitious goal: to understand the Universe in its entirety. Find out more here.

Maths in a minute

Want facts and want them fast? Our Maths in a minute series explores key mathematical concepts in just a few words.

Something from nothing?

If you can prove that a statement can't possibly be false, does this mean it's true?
Citizen science: Schumann resonances

Resonant electromagnetic waves, created by lightning flashes, circle the Earth. Wim Hordijk explores the maths and shows how you can keep track with these phenomena.
Who's watching: Can maths exist if you can't see it?

We explore non-constructive proofs and what happens if you try and avoid them.
Maths in a minute: Truth tables

Introducing an indispensable tool of mathematical logic.
Clocking the schedule

The way many football leagues schedule their fixtures can lead to unfair effects — and unsolved maths problems!