Earendel was observed using an effect where the fabric of space-time is warped by gravity – a phenomenon predicted by Einstein. This causes light to bend as it passes by objects with large masses, like planets, suns, or even galaxies, allowing us to see around and even behind these objects. The effect is known as gravitational lensing and is part of Einstein’s theory of general relativity. Einstein’s theory also has implications for how we experience time, which, as it turns out, is relative. At a most basic level, as NASA explains, we all travel through time at approximately the same speed of one second per second. But the way we experience time changes according to both how fast we are traveling and the way gravity influences space-time.
NASA described an experiment to show that the faster you travel, the slower you experience time. It involved having a clock measuring time on the ground and a clock measuring time onboard an airplane traveling in the same direction as the Earth rotates. After the plane finished its journey around the globe, the scientists found that the clock on the plane had traveled through time slightly slower than the clock on the ground. Because of these same time dilation effects, after spending 1 year in space on the low Earth-orbiting ISS, astronaut Scott Kelly was technically 0.01 seconds younger than his twin brother Mark who stayed on Earth.