The Universe as a Time Machine

Everything we see is always an image of the past

Michele Diodati
Island Universes
Published in
4 min readNov 14, 2021

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Credit: NASA, ESA, P. van Dokkum (Yale University), S. Patel (Leiden University), the 3D-HST Team

As many know, light does not propagate instantaneously but has a finite speed, just under 300,000 km per second. One of the strangest and counterintuitive consequences of this limit is that everything we see, even the closest thing, is always an image of the past.

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Michele Diodati
Island Universes

Science writer with a lifelong passion for astronomy and comparisons between different scales of magnitude.