Space & astronomy
Looking into space also means looking into the past
Light takes time to reach us, so distant views carry older information.
Science & natureCategory
Space & astronomy
Planets, stars, galaxies, and the evidence we use to understand the universe.
Space & astronomy
Why your thumb seems to jump when you switch eyes
A change in viewpoint shifts a nearby object against a distant background.
Space & astronomy
A planet’s path need not be a perfect circle
Kepler’s first law describes planetary orbits as ellipses.
Space & astronomy
Why did an Earth-centred sky seem plausible?
The daily motion of the sky can look as though everything circles Earth.
Space & astronomy
Why does Polaris seem almost still?
It lies close to the direction of Earth’s rotation axis in the northern sky.
Space & astronomy
Why are there two ways to count an Earth day?
A solar day uses the Sun; a sidereal day uses distant stars.