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.

Re:Neat-o.

[Anonymous Coward]

Thanks for your permission. We were staying up days worrying we wouldn't get it.

Re:Neat-o.

[Anonymous Coward]

Your century called; they want their insults back.

Re:Neat-o.

[Anonymous Coward]

the interstellar void called, it wants it's waste of space back.

Re:Neat-o.

[Anonymous Coward]

goatse called. He wants you to crawl into his black hole.

Re:Neat-o.

[Anonymous Coward]

The grocer called: he wants his apostrophe back.

Re:Neat-o.

[Anonymous Coward]

Whenever 2 AC's are fighting I always imagine it's the same person. Very funny.

Next

[Anonymous Coward]

see the light from this explosion centuries later, and learn exactly how it happened.

It went BOOM!

Re:Next

[TechyImmigrant]

see the light from this explosion centuries later, and learn exactly how it happened.

It went BOOM!

No. It went BOOMETY BOOM.

nobody saw it?

[turkeydance]

how would the forked-tongue know?

too dim

[epine]

If no-one could see it because it was too dim to see everywhere on earth, then we probably should describe the source object as "luminous" rather than "bright".

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:too dim

[cpotoso]

Wonderfully said!

But we DID saw it...

[antiperimetaparalogo]

"The Milky Way's Most Recent Supernova That Nobody Saw"

But we DID saw it! The same way we see all things...? Some delay (and reflections/"light-echo") exist even for what i see right now in the monitor... am i blind?

Re:But we DID saw it...

[Bengie]

A super nova that out shined the entire galaxy and the only way we get to see it is via light echos that only powerful telescopes can see. So no, we didn't get to see it with our naked eyes.

Re:But we DID saw it...

[antiperimetaparalogo]

1. Go to zoo.

2. Go in monkey cage.

3. Start grooming monkeys and picking nits off them.

4. GTFO Slashdot forever and stop posting such stupid crap.

Your disappearance would be the greatest contribution you could ever make here.

I can't think how I can "PROFIT" with this business plan fellow Slashdoter? I mean... i am not a charity!

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

[sexconker]

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.

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.
The the light emanating from that explosion that reached us via reflection, it was however long ago we detected those reflections.
Time is relative. Shit traveling near the speed of light experiences much less time than shit at non-relativistic speeds.
HEY! Maybe that's why it's called relativity!

Re:11,000 years ago, not 300

[Anonymous Coward]

Relatively speaking you're wrong, it happened 300yrs ago -- when the light hit earth.

Now, in absolutes; 11300yrs ago (note that 300 years ago the light hit Earth, so you have to add the years up!), a big explosion occurred and probably vaporized a few planets with species on it... So, PETA should be protesting the supernova these physicists are studying for the obliteration of several hundreds of millions of animals. Now way should these physicists be continued to misuse public funds to continue their research.

-The mouth maybe moving but there's no brain activity behind the words...

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

[MobileTatsu-NJG]

So the summary's opening line of "A little over 300 years ago, a supernova ... exploded" is incorrect.

I'm glad this was modded up so that all those people who didn't see that episode with the Picard Maneuver could be brought up to speed.

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

[wonkey_monkey]

"Now" spreads at the speed of light so when you see something, it's happening, as far as you are concerned, right now.

I don't think that's how a physicist would define simultaneity. There is a reference frame in which it happened as arbitrarily close to "now" (in that reference frame) as you'd like, but we're not in one of those.

The event which produced the photons happened, as far as I'm concerned, 11,000 years ago.

If you want to say it's happening "now," then any signal we send back in that direction will also get there "now." Except that that "now" will be 22,000 years later then the first "now," which makes no sense.

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:11,000 years ago, not 300

[Anonymous Coward]

"Now" spreads at the speed of light so when you see something, it's happening, as far as you are concerned, right now.

Thought experiment: Camera, long exposure, fast strobing light. Shutter open, Joe fires a bullet from his gun across a range into a target. At time t(a), the trigger is fully compressed. At time t(b) the hammer has released. At time t(c) the hammer has struck. At time t(d) the powder flashes. At time t(e), the bullet leaves the barrel. At times t(f-h), we see the bullet (after printing the photo) several times in mid-air between gun and target. At time t(i), the bullet strikes the target, at time, t(j) the bullet is halfway sunk into the target, at time t(k), the bullet is flush with the target, at time t(l), the bullet has disappeared into the target.

What time did Joe shoot the target?

We define "now," practically, the instant the photons that hit our eyes are translated to chemical signals and are interpreted into our consciousness. The time it takes for the chemistry we call sight to occur takes considerably longer than the time it takes for the light from local events to strike our retinas. When "now" actually is depends, changes for every single point of space, thus the need for "spacetime." I think conceptually, even in a relativistic universe, an ideal "now" exists if you standardize on where the single point of observation is (with THE clock standardized for the observation), or if you model the vast galactic distances much shorter to represent events. I think this might be called "time slicing," but not sure.

Also, FWIW, Flamsteed probably saw something related to the supernova in 1680

cassiopia a

Re:11,000 years ago, not 300

[yodleboy]

Dark Helmet: What the hell am I looking at? When does this happen in the movie?
Colonel Sandurz: Now. You're looking at now, sir. Everything that happens now, is happening now.
Dark Helmet: What happened to then?
Colonel Sandurz: We passed then.
Dark Helmet: When?
Colonel Sandurz: Just now. We're at now now.

and so on...

Re:11,000 years ago, not 300

[SpaceCommander]

Came here to say this.

Re:11,000 years ago, not 300

[iMadeGhostzilla]

I think the problem is that the question "did the star really explode now or 11000 years ago?" is philosophical as it tries to go beyond the theory. The only thing that matters is that the light -- the information -- has just reached our frame of reference. (Actually 300 years ago.) "Now" only has meaning in our frame of reference.

Simultaneity as you said is a better term, and "according to the special theory of relativity, it is impossible to say in an absolute sense that two distinct events occur at the same time if those events are separated in space." So if, say, I see my alarm clock go off at say 10pm and just then see a star exploding, then the explosion and the alarm activation are happening simultaneously -- as far as I'm concerned.

Now if I had a premonition and wrote down 11,000 years ago "that one star will explode" and indeed the light of its explosion reached me today, then it's true, I had to wait that long, but my writing that down didn't happen simultaneously, in my reference frame, with the star exploding -- it happened 11,000 years before it.

Re:11,000 years ago, not 300

[sexconker]

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.

Light travels at the speed of light, but time is relative.
And you don't know that time means nothing to a photon. They could be sentient spacefarers for all you know.

Re:11,000 years ago, not 300

[wonkey_monkey]

Simultaneity as you said is a better term, and "according to the special theory of relativity, it is impossible to say in an absolute sense that two distinct events occur at the same time if those events are separated in space." So if, say, I see my alarm clock go off at say 10pm and just then see a star exploding, then the explosion and the alarm activation are happening simultaneously -- as far as I'm concerned.

The trouble with that definition of simultaneity is that it's asymmetrical. By that definition, someone sitting at the point of the explosion would disagree that the explosion and your alarm clock going off happened at the same time - he'd have to wait 11,000 years for the light from the alarm clock going off to reach him.

Two observers in the same frame of reference (assuming Earth and the exploding star are not moving very much relative to each other) should agree on the order and simultaneity of events - otherwise it's not much use as a frame of reference.

Re:11,000 years ago, not 300

[Anonymous Coward]

." So if, say, I see my alarm clock go off at say 10pm and just then see a star exploding, then the explosion and the alarm activation are happening simultaneously -- as far as I'm concerned.

Zero proper time (i.e. the points that can be connected by a ray of light) is a crappy definition of simultaneous. There are situations both in special relativity and general relativity where you can get light from an event to pass the same point at different times. Do you want to now say that event happened "now" twice?

Defining simultaneous as when two events are at the same time within a frame works just fine if you remember that it is relative to the frame. In cases like observing things from Earth where there is a clear frame to use, it works really well. This would mean though light from X light years away left X years ago (at distances close enough that expansion of space doesn't matter).

Re:11,000 years ago, not 300

[Anonymous Coward]

Defining simultaneous as when two events are at the same time within a frame works just fine if you remember that it is relative to the frame. In cases like observing things from Earth where there is a clear frame to use, it works really well. This would mean though light from X light years away left X years ago (at distances close enough that expansion of space doesn't matter).

Since as you say there are situations both in special relativity and general relativity where you can get light from an event to pass the same point at different times, do you want to say that an event happened at two different times in the past?

Re:11,000 years ago, not 300

[Anonymous Coward]

do you want to say that an event happened at two different times in the past?

That doesn't follow. Light arriving from an event at two different times took two different paths and would have traveled a different number of light years to get here. The result would be completely consistent, as in both cases you can trace the time it left back to the same point. It is only inconsistent if you base the definition of "now" on the time light arrives, instead of when it left, for a given frame.

Re:11,000 years ago, not 300

[iMadeGhostzilla]

You're right. I can only say that my detection of light from the exploding star and the detection of alarm clock going off have happened simultaneously. And if my alarm clock is 11,000 light years away in another direction, if I detect its light and the star's light simultaneously, I can infer that the alarm and the star went off at the "same time". At the same time for me, that is. For someone who was moving at the time, not necessarily.

I'm still not quite convinced that I can talk about events that I can't measure/observe in principle. I.e. the detection of the exploding star's light in my telescope is an event I can observe. It appears that the explosion of the star itself at its point in space is not. But I think I see that I can use this inference about a non-observable/imaginary/abstract event to establish order and therefore potential causality or lack of it among events, which is the utility of the theory. Thanks for explaining that.

Re:11,000 years ago, not 300

[RandomAdam]

But they must be drunk; because they are always bouncing off stuff.

Old question

[Tablizer]

If a tree explodes in the forest...

Re:Old question

[jrumney]

If a tree explodes in the forest...

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

Re:Old question

[Anonymous Coward]

...it is seriously fucking cold there.

Re: Old question

[Anonymous Coward]

Or you might be an Australian.

Eucalyptus trees are like all things from that benighted land...dangerous.

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.

Re:Old question

[jrumney]

It's is a perfectly good use of the possessive singular of it, seen throughout historical texts like the US constitution. I reject the revisionism that brought about the artificial word its so that grammer nazis can start flame wars on internet forums.

Re:Old question

[ScentCone]

No. "It's" is a contraction of "it is," and "its" is possessive in a form much like the word "his." What you're rejecting is clarity in communication. Why?

Re:Old question

[jrumney]

It's perfectly clear from context. There is no need for revisionism in the language purely for the sake of looking down on those who do not follow your rules.

Re:Old question

[ScentCone]

Your write. Theirs know raisin too every extinguish between too words that seam clothes enough in how they sound.

Why evolve a language into a form that's clearer and easier to use, right? Right! All of this revisionism is nonsense, and we should be sticking with Ye Olde English. Or better yet, a bit of Chaucer-style middle English, right? Of course, he was a revisionist bastard wasn't he! He was probably looking down on those primitive Anglo-Saxons and their "clear from context" runic vagueness. We should all be speaking proto-German so as not to come across acting superior by simply wanting to be clearly understood.

Lazy, inconsistent use of basic punctuation things like possessive forms indicate a lazy mind. The point isn't that using the correct form is the rule-followers lording it over the hipster rebels. The point is that when their are two very distinct and clearer different (meaning) forms used by, oh, a billion people or so to mean very specific, very different things in routine usage, the person who sloppily muddles them together is deliberately deciding to be LESS clear as a communicator.

Why have dozens of different words for the color blue, right? Why bother with more than one word that means "fast" or more than one term of affection or disregard? Because the wider, richer language makes it possible to communicate more eloquently, succinctly, and with clearer purpose. Lazy communicators like to waste other people's time. They're the ones who drive slowly in the left lane, stand in the way in a store aisles while TXTing, and just generally aren't thinking about whether they way they interact with the rest of the world exhibits, or doesn't, any sort of thoughtfulness. Taking a complex, precise set of choices about which word or form to use, and dumbing it down through blurring and muddling of usage ... THAT is the revisionism you should be fretting about. Because it's culturally toxic. It erodes, rather than sustains the sort of communal intellect we need in order to improve society.

I'm getting better

[Anonymous Coward]

at detecting which articles link to fucking medium.com

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.

Re:Summary.... Incorrect

[OdinOdin_]

Maybe the original light should have arrived 300 years ago (due to Earth being 11,000 LY away from source), but the reflected echo is coming to us only now (since the reflection traveled further) ?

Re:Summary.... Incorrect

[Anonymous Coward]

You pedantic dumb fucks annoy the shit out of me. Yes, anyone with half a brain knows that if it was 11000 years away, that's precisely when it actually occurred -- just as anyone with half a brain knows that TFA is speaking in OUR frame of reference when saying it occurred 300 years ago, dipshit. No need to spell that out to sound "smart."

We know what a supernova is

[Anonymous Coward]

A little over 300 years ago, a supernova â" a dying, ultramassive star

This is /., not some random Joe Blow news site. We KNOW what a supernova is, thank you.

300 years ago?

[rossdee]

"A little over 300 years ago, a supernova ...exploded."

If it exploded 300 years ago or so then for us to know about it, it must have been within 300 light years of us, thtats a bit close for my liking

Re:300 years ago?

[david_thornley]

Depends on the reference frame you're using. Saying it exploded when the light hit us is perfectly correct, in the frame of reference of the light. It's a useful frame of reference, in that we can refer to times without bothering to determine exactly how far away the explosion was (and what frame of reference do we use for that?), and because we can specify events as they appear to us without having to subtract a large and arbitrary number.

A supernova does not explode

[Anonymous Coward]

There is a mistake in the summary: "A little over 300 years ago, a supernova — a dying, ultramassive star — exploded, ..."

A supernova does not explode; a supernova _is_ an explosion of a star.