Lookback time refers to the amount of time that has passed since the light from an astronomical object was emitted until it reaches an observer. This concept is crucial for understanding observations of high-redshift galaxies, as it provides a way to connect the light we see today with the historical state of those galaxies in the early universe, essentially allowing us to look back in time to study their formation and evolution.
congrats on reading the definition of Lookback Time. now let's actually learn it.