Frozen in Time?

When we observe the Universe, we are looking back in time. We see it how it was, not how it is. What are light-travel time effects?

A lecture by Katherine Blundell OBE, Gresham Professor of Astronomy
23 October 2019 1PM BST
https://www.gresham.ac.uk/lectures-an...

Most information from outer space reaches us at the speed of light and this governs our understanding of time and evolution in the cosmos. When we observe the Universe, we are “looking back in time”: we see the Universe as it was, not how it is. This is actually very helpful as we seek to discern and understand cosmic history and how the Universe has changed since earlier times.

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