How to Catch a Supernova Rerun

On earth a sound echo lets you hear something again. Over great distances, a light echo can let you see something again, specifically an exploding star.

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Sources:
Armin Rest (interview): http://www.stsci.edu/institute/smo/general-information/staff/biography?user=arest
http://www.pas.rochester.edu/~blackman/ast104/brahe10.html
https://history.nasa.gov/SP-466/ch9.htm
https://www.cfa.harvard.edu/news/2008-11
https://arxiv.org/pdf/astro-ph/0210534.pdf
https://arxiv.org/pdf/0805.4607.pdf
https://arxiv.org/pdf/1003.5660.pdf
http://cxc.harvard.edu/cdo/snr09/pres/Rest_Armin.pdf
https://arxiv.org/pdf/0810.5106.pdf
http://www.spitzer.caltech.edu/images/2662-ssc2005-14d-Illustration-of-a-Light-Echo
https://www.youtube.com/watch?v=nrQM0KZgQj8
https://tigerprints.clemson.edu/cgi/viewcontent.cgi?article=2640&context=all_dissertations
http://www.astronomycast.com/2011/03/ep-215-light-echoes/
https://arxiv.org/pdf/1705.05405.pdf
https://www.nasa.gov/content/hubble-highlights-seeing-light-echoes
http://philosophy-of-cosmology.ox.ac.uk/variability-of-realm-of-fixed-stars.html
http://chandra.harvard.edu/photo/2016/tycho/
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Images:
https://en.wikipedia.org/wiki/File:Tycho_Cas_SN1572.jpg
https://images.nasa.gov/details-PIA13119.html
https://images.nasa.gov/details-PIA11435.html
https://svs.gsfc.nasa.gov/11233
https://www.spacetelescope.org/videos/opo1742a/
http://hubblesite.org/image/4088/news_release/2017-42
https://svs.gsfc.nasa.gov/30956
https://www.spacetelescope.org/videos/astro_bn/
https://svs.gsfc.nasa.gov/11080
http://www.spitzer.caltech.edu/video-audio/762-ssc2005-14v1-The-Cry-of-Cassiopeia-A
https://svs.gsfc.nasa.gov/11233