

Astronomers Watch a Supernova and See Reruns - fspeech
http://www.nytimes.com/2015/03/06/science/astronomers-observe-supernova-and-find-theyre-watching-reruns.html

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anigbrowl
This the most exciting astronomical development I've heard about for several
years. One gets the impression that there might be perspectives like this all
over the place, much as the discovery of the first few exoplanets was followed
by an avalanche of others.

Am I right in thinking that the temporal offsets of the gravitational lensing
allow for a sort of controlled experiment, eg where astronomers study the
oldest image of the supernova and form hypotheses about its development, then
test those hypotheses against the later ones?

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semaphoreP
Not quite, I think. The supernova is more used to study the dark matter lens,
which cannot be seen directly. Seeing the supernova being lensed by different
parts of the galaxy cluster will allow them to map the dark matter profile of
the galaxy and study how it's distributed.

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dynofuz
I used to think about this: Would it be possible to find a configuration of
galaxies with enough mass to bend light from one point on earth back to
another point on earth? If we could do that, we actually look at an older
timestamp of earth.

Yes, we'd need a reeeeally powerful telescope, but maybe we could find that in
another configuration of galaxies as well.

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thret
Yes, it is possible, but we'd need better telescopes. This post has a pretty
good analysis: [http://rein.pk/gravitational-lensing-to-observe-ancient-
eart...](http://rein.pk/gravitational-lensing-to-observe-ancient-earth/)

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ovidiup
The whole series of videos about various astronomic subjects is extremely well
done. The music and narration of Dennis Overbye remind me of the old Carl
Sagan movies, this time made for the newer generation, with a shorter
attention span.

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MilesTeg
If we had powerful enough telescope that we could see a civilization growing
up 1000 light years away we could record it and provide it as a gift for when
we finally meet. Or maybe there is someone out there doing that for us.

