the.com/parallax
the reason your thumb leaps when you wink one eye at a time
means The apparent shift in an object's position when you view it from two different vantage points — and the technique that uses that shift to measure distances, especially to stars.
from From Greek 'parallaxis,' meaning alteration or change, built from 'para-' (beside, alongside) and 'allassein' (to change, from 'allos,' other). It entered scientific use through astronomy, where the tiny apparent wobble of nearby stars against the distant background — seen as Earth swings to opposite sides of its orbit — became the first real yardstick for the cosmos.
- star ruler
- Measures distances to nearby stars by Earth's orbital shift
- unit origin
- The parsec is literally named after parallax seconds
- game depth
- Layered backgrounds scroll at different speeds to fake 3D
- camera lie
- Why viewfinders once framed shots slightly wrong
- brain trick
- Two eyes exploit it to build your depth perception
stellar parallax measurement — hipparcos satellite measured star distances using parallax shifts, enabling the cosmic distance ladder
parallax scrolling video games — sonic the hedgehog (1991) used layered backgrounds moving at different speeds to create depth
moon parallax lunar distance — ancient astronomers used lunar parallax to calculate the moon is ~384,000 km from earth