The Milky Way's Most Recent Supernova That Nobody Saw

StartsWithABang writes: A little over 300 years ago, a supernova — a dying, ultramassive star — exploded, giving rise to such a luminous explosion that it might have shone as bright as our entire galaxy. And nobody on Earth saw it. Located in the plane of our Milky Way galaxy, the light was obscured, but thanks to a suite of great, space-based observatories (Hubble, Spitzer, and Chandra), we've been able to piece together exactly what occurred. Not only that, but observations of a light-echo, or reflected light off of the nearby gas, has allowed us to see the light from this explosion centuries later, and learn exactly how it happened.

Comments

Neat-o.

[mythosaz]

Every time I see a cool space/science story, despite having been an adult for some time now, I still get an awesome sense of "wow" out of it.

Keep on exploring the mysteries of the universe guys.

11,000 years ago, not 300

[doug]

TFA says it was 11,000 light years away, so it took 11,000 years for the light to get to Earth. We should have seen it 300 years ago, but the explosion was a long time before that. So the summary's opening line of "A little over 300 years ago, a supernova ... exploded" is incorrect.

Re:11,000 years ago, not 300

[PPH]

Shit traveling near the speed of light experiences much less time than shit at non-relativistic speeds.

I don't think relativity enters into this. In space, light travels at the speed of light. And to a photon, time means nothing.

What we have here is a direct path length from the supernova to earth of 11,000 ly. Something went 'bang' 11,300 years ago, so we missed the first signals. But there are gas clouds and other crud floating around which reflect the pulse, making it travel longer paths. We are now seing the reflections with path lengths of 11,300 ly. And as time goes by, we will see reflections with longer and longer path lengths.

This will (in time) be an interesting opportunity to map the structures of the gas clouds surrounding the supernova using successive images (over dozens or hundreds of years) and calculating path differences and the underlying 3D structures causing the reflections.

Re:11,000 years ago, not 300

[iMadeGhostzilla]

No that is the whole point of the Relativity Theory. There is no absolute time or "God time", there are only points in timespace. 300 years ago here on Earth if you could see the photons of the explosion, you were witnessing the explosion exactly as was happening. "Now" spreads at the speed of light so when you see something, it's happening, as far as you are concerned, right now.

Re:11,000 years ago, not 300

[thegarbz]

To a relatively stationary you 11000 ly from the source, it was about 11000 years ago.
To the light emanating from that explosion that reached us (unnoticed), it was 300 years ago.

Time slows down when I read slashdot comments like this.

Re:too dim

[khallow]

If you read the story, you find that it wasn't too dim to see, there was just something in the way. And if you can see a supernova from the far side of Earth, you are way too close.

Re:Old question

[ScentCone]

...and you happen to have a mirror handy, you might just catch it's light echoes.

My mirror was destroyed by extraneous apostrophe shrapnel from the exploding tree, you insensitive clod.

2008 wtf?

[I4ko]

How is this news? The video in TFA is from 2008, check the upload date on Youtube. There must be some weird time dilation effect going on, posting 2008 news is a new low, even for ./ on nowadays.

Re:2008 wtf?

[Kozar_The_Malignant]

Indeed. Also a wikipedia article, articles going back several years in Astronomy and Sky and Telescope magazines indicate this may not be "news." Also, this is not the Horrendous Space Kablooie.

Summary.... Incorrect

[aepervius]

Cassiopeia is 11.000 LY away. The star exploded not 300 years ago, but the explosion light reached us 300 years ago. Heck even the article says it wrongly "A supernova dating back to the 17th centuryâSâ"âSthe most recent one in our galaxyâSâ"âSwith a massive black hole left behind. 11,000 light years distant". It might be a bit pedantic, but instead of stating the star exploded 300 years ago, one should say the light of the explosion reached us 300 years ago.