14 DAY TRIAL // In this new video released by the Royal Greenwich Observatory in the UK, Dr. Olivia Johnson explains how astronomers use a phenomenon called parallax, standard candles such as Cepheid variable stars, and galactic redshift to measure distances in the Universe.
I think that she provides a very accessible explanation for a part of astronomy that is inherently complex. Measuring distances in an expanding Universe is a process that needs to include countless variables, and whose results can be dramatically altered by even the smallest errors.
Yet, Dr. Johnson manages to explain the connection between parallax, standard candles and redshift in an unambiguous way. She also shows how measurements of distances in the solar system, such as the one separating the Earth from the Sun, relate to determining the location of standard candles.
Finally, she provides a brief explanation of redshift and blueshift, which are both changes in light caused by the Doppler effect, and which help us measure distances in an ever-expanding Universe.