How do scientists measure distances to stars and galaxies?

Measuring distances in the vast universe is a fundamental task in astronomy and astrophysics. Scientists utilize various techniques to determine the vast cosmic distances to stars and galaxies.

Parallax:

Parallax is a common method for measuring the distances to closer stars. Scientists observe how a star appears to shift against distant background stars as Earth orbits the Sun. By measuring this apparent shift, they can calculate the distance to the star.

Redshift:

For more distant objects like galaxies, scientists use redshift. This phenomenon occurs when light from an object shifts towards longer wavelengths due to the expansion of the universe. By analyzing the amount of redshift, scientists can determine the distance to galaxies.

Standard Candles:

Another method involves using standard candles, which are objects with known luminosities. By comparing the observed brightness of these objects with their intrinsic brightness, scientists can calculate their distances. Examples of standard candles include Cepheid variables and Type Ia supernovae.

By combining these techniques and advancements in observational astronomy, scientists can accurately calculate distances to stars and galaxies, providing valuable insights into the vast expanse of the universe.