THE FIRST EDITION — ON TIME
Ideas that change how we see the world.
And the people who helped us see them.
Physics / 5 min read
Special relativity describes flat spacetime; general relativity makes gravity part of its geometry. Explore the difference through clocks, free fall, and Einstein’s elevator.
Read the storyPhysics / 5 min read
Moving clocks can measure less elapsed time. Here is what time dilation means, why it happens, and what a journey at 80% of light speed would look like.
Read the storyHistory / 4 min read
Light, atoms, space, and energy: a guide to Einstein’s four landmark papers of 1905, and why his story is bigger than a lone-genius myth.
Read the storyPhilosophy / 4 min read
The block universe treats events across time as part of one spacetime. Explore eternalism, presentism, and why relativity does not settle every philosophical question.
Read the storyEXPLORE TIME / THREE CONNECTED ARTICLES
A three-article introduction to time: learn why clocks can disagree, discover Einstein’s ideas, then explore whether the future already exists. Read in order, or choose the question that interests you.
TRY IT YOURSELF
A free, ten-minute activity: make a prediction, test four speeds, and check your explanation.
Start the time-dilation activity ↗FROM THE OBSERVATORY
We connect scientific ideas with their history and philosophical consequences. Clear explanations, useful visuals, and sources you can follow.
Our editorial approach ↗