Parallax method

The parallax method measures the apparent shift of an object against distant background references when viewed from different positions. For example, when you hold your finger in front of your face and look at it with one eye closed, then switch eyes, your finger appears to move against the background. Similarly, astronomers observe nearby stars from different points in Earth's orbit around the Sun, noting their slight positional shifts against distant stars. This tiny shift—the parallax angle—helps calculate the star's distance. It's a fundamental technique for determining how far objects are in space by using geometric principles.