When we look through a telescope, we are not simply observing distant objects in space—we are looking back in time. This idea sounds almost poetic, yet it is grounded firmly in physics. Every star, galaxy, and nebula visible through a telescope is seen not as it exists “now,” but as it existed in the past. Some objects appear as they were a few years ago, others millions or even billions of years ago. In this sense, telescopes are time machines, allowing humanity to study the history of the universe by collecting ancient light.