How far away is the nearest star?

Besides our Sun, the nearest star to Earth is **Proxima Centauri**, which is part of the Alpha Centauri star system. Proxima Centauri is located approximately **4.24 light-years** away from Earth. To put that into perspective, one light-year is the distance that light travels in one year, about 5.88 trillion miles (9.46 trillion kilometers). So, Proxima Centauri is roughly 25 trillion miles (40 trillion kilometers) away from us. Astronomers measure such vast distances using a variety of methods, with one of the most fundamental being **stellar parallax**. Parallax is the apparent shift in the position of a nearby star against the background of more distant stars when observed from different positions in Earth’s orbit around the Sun. By measuring the angle of this shift and knowing the diameter of Earth's orbit, astronomers can calculate the star’s distance using simple trigonometry. This method works well for stars up to a few thousand light-years away. For more distant stars and galaxies, astronomers use other techniques such as standard candles (like Cepheid variables and Type Ia supernovae), redshift measurements, and the cosmic distance ladder—a series of overlapping methods that build on each other to measure progressively larger distances in the universe. In summary, the closest star beyond our Sun is Proxima Centauri, about 4.24 light-years away, and astronomers rely on geometric and observational techniques like parallax to measure these enormous distances.