DescentBB

Posted: **Wed Dec 08, 2004 2:08 am**

http://antwrp.gsfc.nasa.gov/apod/ap030402.html

weird, i've never even considered that light can echo like that. but it makes sense when you think about it, and even more sense when you can just simply watch it on the animated gif in the link

.

...what is seen in the above four-frame movie is actually an outwardly moving light echo of the bright flash. The actual time-span of the movie is 8 months during 2002. In a light echo, light from the flash is reflected by successively more distant rings in the complex array of ambient interstellar dust that already surrounded the star...

Posted: **Wed Dec 08, 2004 7:33 am**

Instead of "echo' would the term "relection" be more appropriate?

Posted: **Wed Dec 08, 2004 8:05 am**

perhaps not, an echo is basically a reflection that is noticeably mollested because of it's lack of relative speed.

the dust is reflecting the light as the expanding light ring... uh expands.

sound echos are cool because they force us to think of sound as non-instant. this echo does the same with light.

Posted: **Wed Dec 08, 2004 8:16 am**

Echo is a misleading term (in some ways) for what is occuring, while it may be highly accurate in some ways, the typical understanding or usage/connotation of "echo" is the return of a signal to the source, be it sound, radar or whatever.

But yes, super cool event.

Posted: **Wed Dec 08, 2004 12:50 pm**

Interesting...

DescentBB

light echo?

light echo?