The Sun's gravity is so powerful that it actually bends light from distant stars.

Albert Einstein published his theory of general relativity in 1915, proposing that gravity is not a force but a curvature of spacetime caused by mass. To test this, British astronomer Arthur Eddington traveled to the island of Príncipe for the solar eclipse of May 29, 1919. By photographing stars near the eclipsed Sun, he observed that their positions shifted by about 1.75 arcseconds, exactly as Einstein predicted.This phenomenon occurs because light follows the shortest path through curved space, a process known as gravitational lensing. While the Sun's effect is measurable, much larger objects like galaxy clusters act as massive cosmic magnifying glasses. These clusters can bend light from galaxies billions of light-years away, allowing NASA's James Webb Space Telescope to see the early universe.Gravity also affects the passage of time, a concept known as gravitational time dilation. Clocks closer to a massive body tick slower than those further away. This is a critical factor for Global Positioning System (GPS) satellites orbiting 20,200 kilometers above Earth. Without correcting for these relativistic effects, GPS locations would drift by more than 10 kilometers every single day.