When observing a very distant quasar, we are actually seeing the universe the way it waswhen it was much younger than it is today.

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Quasars are extremely distant objects, some of which emitted their light billions of years ago. Light takes time to travel through space, so the light we observe from a quasar today actually left the quasar many years ago. By observing a very distant quasar, we are seeing the universe as it was when that light left the quasar, which can be many billions of years ago. Therefore, we are seeing the universe when it was much younger than it is today. Quasars are some of the most distant objects in the universe and their light can take billions of years to reach Earth. This means that when we observe a quasar, we are seeing light that was emitted when the universe was much younger than it is today, providing important information about the early universe.

When Observing a Very Distant Quasar, We Are Actually Seeing