The universe is truly huge. It stretches for at least 13.5
billion light years (1.277×1023 km) in every direction
(considerably further in fact), and its massive size poses an
equally large problem how can you accurately measure how far
away objects are? Over such large distances conventitional
methods of measuring distances (like using the time taken for
light to hit and object and reflect back) become impractical and
very, very slow. Thankfully astronomers can use other methods
developed over the years to deal with these monumental universal
distances. The three main methods they can achieve this are: -
Cepheid variables - and Redshift Parallax uses changes in the
relative positions of celestial objects throughout the year to
estimate how far away they are using trigonometry. A star that
is closer to the Earth will appear to move more than a star that
is further away. The same principle applies when you look out of
the window in a moving car, objects close to you wizz past while
those in the distance move l