Talk:Light echo

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"light following paths B and C appear to come from the same point in the sky to the observer"[edit]

With the current illustration, that is not true. Could somebody correct the illustration so that paths B and C are truly co-linear? 71.219.229.17 (talk) 17:06, 17 October 2009 (UTC)[reply]

Yeah this was confusing the hell out of me Cytokinetics (talk) 06:03, 23 February 2014 (UTC)[reply]

Edited the image to hopefully make it a little clearer Cytokinetics (talk) 06:35, 23 February 2014 (UTC)[reply]

Only example?[edit]

Are you sure that V838 Mon was the only observed light echo since 1936? Here are some links that analyse light echoes around other supernovae: Multiple Light Echoes from Supernova 1993J, Sugerman & Crotts, ApJ 2002; A New View of the Circumstellar Environment of SN 1987A, Sugerman, Crotts, Kunkel, Heathcote & Lawrence, ApJ, 2005. Searching citebase for some of the authors mentioned also reveals similar papers. SamGeen(talk)

  • I was going off the information provided by the ESA on that one. Certainly if there are other examples that can be dug up then by all means they should be added to the article! Arkyan • (talk) 14:42, 20 April 2007 (UTC)[reply]
Yes, I don't know what the ESA site meant. Possibly it was referring to direct observations; the methods used in the papers appear to be difference methods, where the flux in the two images is subtracted to remove bright, constant light sources like stars. I don't know whether the ESA site meant direct observations without using difference methods. In any case, it's only something I've come across for project work - I don't know a huge amount about it. SamGeen(talk) 18:04, 20 April 2007 (UTC)[reply]

Incomprehensible logic[edit]

"Because this light has only traveled forward as well as away from the star [...]"

Is there a word missing here? "Only" implies exclusivity, "as well as" implies inclusivity. Both cannot be correct.

"Since the speed of light is a constant, all light that originates from the same flash must have traveled the same distance."

Uh, no - only those arriving at the same time. If this statement is a locical continuation of the previous paragraph, they should not be separated. Geira (talk) 16:31, 22 February 2011 (UTC)[reply]

Where is the author of this article? I'd fix it myself if only I could understand it! Neither the "Because this light has only traveled forward as well as away from the star..." statement nor the "...light following paths B and C appear to come from the same point in the sky to the observer..." statement are understandable. Please fix this article. 71.139.179.193 (talk) 00:33, 22 December 2012 (UTC)[reply]

Yes, please! This is still incomprehensible. And

For example, a light echo is produced when a sudden flash from a nova is reflected off a cosmic dust cloud, and arrives at the viewer after a longer duration than it otherwise would have taken with a direct path. Because of their geometries, light echoes can produce the illusion of superluminal speeds.

is understandable but seems to be nonsense. If the echo arrives later than the original signal, how can it be thought to have traveled faster? Maybe an observer thinks the echo is the direct signal and the direct is an echo, but then the article should say so explicitly rather than leave the reader in confusion. --Thnidu (talk) 16:36, 26 February 2018 (UTC)[reply]

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