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Astronomy

Understanding Redshift and Blueshift in Galaxy Observations

Quick fact

The most distant galaxy ever observed, GN-z11, has a redshift of about 11.09, meaning its light has traveled for over 13.4 billion years to reach us.

Why this is interesting

When we look at distant galaxies, their light tells us they are moving away from us—but how can we possibly know that just from the colors we see?