For nearby stars (up to a few hundred light-years):
* Parsecs (pc): One parsec is approximately 3.26 light-years. It's defined based on parallax, the apparent shift in a star's position against the background due to Earth's orbit around the Sun.
* Light-years (ly): This is the distance light travels in one year. While it's a more intuitive unit for understanding distances, parsecs are often preferred for scientific calculations.
For stars farther away:
* Kiloparsecs (kpc): Equal to 1,000 parsecs.
* Megaparsecs (Mpc): Equal to 1,000,000 parsecs.
* Gigaparsecs (Gpc): Equal to 1,000,000,000 parsecs.
Other less common units:
* Astronomical Unit (AU): This is the average distance between Earth and the Sun. It's used for distances within our solar system, but less common for stars.
Important Note: As we delve into the vastness of the universe, it becomes increasingly difficult to directly measure distances. Therefore, astronomers rely on various techniques and standard candles to estimate distances to faraway objects.
