I thought I might be seeing a new supernova once when I was a kid. I was an avid amateur astronomer then, so I knew that the bright point of light I was seeing was not supposed to be there, and it showed no apparent motion even though I watched for a while. I went in and got binoculars and could still see no apparent motion. I then went to get my telescope and set it up, and by then I could see there was some motion, so the thing could not be a supernova.

The motion got faster and faster, and it soon became apparent what it was. It was a B-52 very far away heading for an air force base that was 3 miles from our house, with its front light on, descending in a way that had it coming almost straight at me.

Very cool, but can't help to wonder.. What is the likelihood of taking a random picture that captures the start of a supernova? How often does one happen in a given photograph-sized portion of space?

Because astronomics is involved it feels like one of those things that either happens all the time or has a 1 in 10^100 chance of happening.

Is there another plausible explanation here? Some kind of eclipse maybe.

I've seen rates of supernova for the milky way as 1 per century. So that's 1 per 10^13 star-years.

With 10^22 stars in the observable universe distributed uniformly we would expect something like 10^9 stars to supernova this year.

But we have to consider the speed of light. So what we are really asking is something like what is the probability that light will arrive at Earth in some interval from a supernova.

I'd imagine this is some integral over spherical shells receding into the distant past where there is some function defined on the shell which tracks stellar density as well as supernova probability. Beyond my expertise to even attempt napkin math.

> But we have to consider the speed of light. So what we are really asking is something like what is the probability that light will arrive at Earth in some interval from a supernova.

We really don't. (We've already largely accounted for it, by only counting the stars in the observable universe.)

So yes, stars supernova at a rate of ~30/second, from our current frame of reference. However, many of them are occluded by dust, or are too faint to differentiate from their neighbours/parent galaxies, or are too red-shifted away...

From the Nature paper:

"We note that the chance probability of this discovery is of the order of 10^−6 assuming a duration of 1 h and one supernova per century per galaxy. If we consider other factors, such as the sky conditions of the observing site and the location of the supernova away from bright host-galaxy regions, then this probability decreases by one order of magnitude."

Remember the principle of multiple endpoints. We only noticed this one example because it hit; we never notice all the cases that don't.

If between 10^6 and 10^7 cameras have been tried out by taking pictures of space, then this one supernova incident is right at about the expected value.

This would only be true if people pointed at random galaxies in the sky. There are only a few thousand galaxies in the NCG catalog that an amateur would even be able to see, and only a few dozen that an amateur would actually be interested in photographing.

Duration of 1h??

That's... astonishing.

Apparently they happen about 3 times a century in the Milky Way. That's not very often, but we can see a lot of galaxies...

https://en.wikipedia.org/wiki/Supernova#Discovery

Did the MW all form around the same time? What I'm getting at is: will the rate of supernova increase as the stars which make up the Galaxy reach end-of-life at approximately the same rate? Will it fizzle like pop rocks at the end?

The longest lived stars, red dwards, will most likely simply fizzle out like a hot plate you turned off. It is unlikely we will ever observe such an event.

Even our Sun doesn't go Supernova, it just blows up a bit and discards it's outer layers, forming a white dwarf.

The stars that go Supernova are much more massive (around 3 times, IIRC) and have orders of magnitude shorter lifetimes (measured in only a few hundred million years at best).

Galaxies can undergo bursts of star formation which are accompanied by lots of supernovae, because supernovae come from massive stars which don't live for very long. The universe was most active in star formation and supernovae about 10 billion years ago.

The lifespans of stars vary by orders of magnitude. The sun is about 4.5 billion years old and is not massive enough to ever be a supernova. Betelgeuse, a candidate to go supernova 'soon' is only about 10 million years old.

Beautiful story of parents passing down inspiration to their child. Don't forget it is social capital that will always be the greatest inheritance.

As a fellow self-taught astronomer, I would have appreciated less of the 'story telling' and more of the details. None of my parents are much interested in astronomy, but I am. If all astronomers only had parents interested in astronomy, then astronomy would have died centuries ago.

I don't really care if his/her's dog's neighbor's boyfriend's aunt did XYZ that was tangentially related. Alas, that type of mush 'sells' page views.

You can find the letter submitted to Nature quite easily. The story is terrific and will follow you there as well, though. He's listed as a co-author along with his affiliation - his rooftop rig, the Observatorio Astronómico Busoniano. If that doesn't give you the warm fuzzies, having a supernova go off in your living room probably won't either.

It's entirely possible that you're neurotypical but you may want to get checked out for ASD.

This crosses into personal attack, or is at least unduly personal in a way that breaks HN's guidelines. Please read those and follow them when commenting here: https://news.ycombinator.com/newsguidelines.html.

If you think you can divine such a diagnosis from a one paragraph comment on a forum explicitly populated by tech nerds that might want to read about gritty technical details via the kind of intellectual curiosity that is in no way unneurotypical, you might want to get checked out for narcissistic personality disorder.

Please don't reply to a bad comment with another bad comment. That just makes the thread worse. Instead, if you have karma > 30, flag the comment as described at https://news.ycombinator.com/newsguidelines.html and https://news.ycombinator.com/newsfaq.html.

>The moment he saw the brilliant light captured by his camera, “it all clicked” for Victor Buso: All the times his parents woke him before sunrise to gaze at the stars, all the energy he had poured into constructing an observatory atop his home, all the hours he had spent trying to parse meaning from the dim glow of distant suns.

It sounds to me that the sweat capital this guy poured in dwarfs by far the "social capital" of inspiration that the rest of us could have (and often) got from watching PBS shows.

It likely did, but that's why its even more remarkable, for social capital has a multiplying effect. Every parent wishes their child to surpass them in the end. All of this makes me think of that Created Equal episode of Milton Friedman's Free to Choose, https://youtu.be/YRLAKD-Vuvk?t=650 as well as the talk about family inheritance https://youtu.be/hoFdVuqrMZw?t=3928

I'm somewhat amused that, although this article suggests that Buso's work was vital to the Nature paper, as does the first sentence of the paper itself, he is author 7 out of 21: https://www.nature.com/articles/nature25151

Journal authors are like executive producer credits. I kind of get why but it also feels like total nonsense. Don't they have acknowledgements? Or is that section not special enough because of how journal indexing happens?

Did the admins change the link without acknowledging it anywhere? I assume all of the comments about the "great story" are referring to the WaPo article, which I only found after several minutes of trying to find a "Page 2" button on NYT and switching tabs back and forth. The "story" on NYT is nonexistent and contains no more information than the headline about this story I read yesterday.

There really needs to be a more formal mechanism for changing links. At least notify us and put the original in a comment!

Does this help? https://news.ycombinator.com/item?id=16434741

Ah, so it wasn't even the Washington Post article! Thanks. Just wish there were a more formal system.

How would an amateur bring this to the attention of the big telescopes so quickly? Are there alert mailing lists with people screening them?

You can send an astronomer's telegram: http://www.astronomerstelegram.org/

There's a pretty active community of amateur astronomers who search for new supernovae. Until recently amateurs actually discovered most new supernovae. Japanese amateurs especially found a lot because there's nothing over the Pacific, so they could discover all the supernova that went off when it was night over the Pacific.

Thanks, interesting! I think this may be the relevant "telegram" for this story?

http://www.astronomerstelegram.org/?read=9521

Putting a damper on the feeling of immediacy the writer seems to have built into the piece, that star flamed out some 80 million years ago during our Cretaceous Period when T Rex, Triceratops et al roamed the earth!

While thats true, if the photographer had been a few days earlier or later their timing wouldnt have been right - so it is very much an immediate thing.

Yes, but T Rex, et al never made a note about it. Bloody typical! That's why it was such a last minute fiasco to take the picture. It's a miracle it got done, to be honest. Quite a bit like my job in some respects...

Simultinaity is relative.

http://visualrelativity.com/LIGHTCONE/minkowski.html

Does 80 million light years mean 80 million years ago? If the star is moving away from us fast...

I think so; while it is moving away from us, 80 million years ago it exploded and sent its light our way. Because it's moving away from us, the light is stretched out a bit, causing red shift, allowing us to have a good idea of distance / time.

I don't know how far the remains have traveled from us since then though.

Alternate link if you're unable to view content at mercurynews: https://www.washingtonpost.com/news/speaking-of-science/wp/2...

How is this even allowed? It's just a repost of the Washington Post article but behind a paywall.

Anyways what a find. It makes me wish I had a high powered telescope and a good place to look up.

It's a common practice for papers to print articles from other publishers. You'll note that it's credited to the Washington Post in the byline. WaPo has their own paywall rules, FWIW.

Thank you. I really wish HN would mark paywalled articles.

Yes, I'm surprised it's even allowed to post an article that is not free for all to read.

There are more details in this piece, the astronomer was taking just 20 second exposures so he really did witness the breakout phase: http://www.skyandtelescope.com/astronomy-news/amateur-astron...

I once accidently captured a supernova in the Fireworks Galaxy (I was aiming for a nearby nebula and missed), but this was one that had been visible for several weeks previously. This was with pretty modest equipment, a 135mm lens and DSLR.

I was expecting to be underwhelmed by the discovery, but that truly is a remarkable story.

Does anybody have information about the details of the process of a supernova? How long does it take from the star collapse to the actual explosion or how does the energy output change over time?

According to https://en.wikipedia.org/wiki/Type_II_supernova, the actual explosion is a few seconds long. 99% of it escapes as a neutrino burst. However about 1% of the emitted neutrinos get absorbed by the start, and that causes the visible explosion.

According to http://astronomy.swin.edu.au/cosmos/T/Type+II+Supernova+Ligh... it takes a few hours for the expanding star to cool down and expand enough to hit maximum visible light. And then the decay thereafter is very slow.

Thanks! The scale of such an event is way beyond anything one can possibly imagine.

what is the elapsed time between the image sequences? how long can elapse between a supernova being first visible and the state of it not being visible?

Supernovae become super bright super quickly, and then taper off. This is why there is a lot of interesting science to be done right at the beginning: they are hard to catch. Depending on many factors they can stay visible for months. The best way to visualize this would is with a Google image search for "Supernova lightcurve" https://www.google.com/search?q=supernova+light+curve&tbm=is...

A few days to months.

https://en.wikipedia.org/wiki/Supernova

I am curious as to how long, in terms of hours/days, it took for the flash to become visible and then extinguish? The article makes it seem like it was over a day or two, but is that generally how long a supernova event will take? I was of the belief that it was a very brief event lasting only an hour or so?

The flash appeared between two 20 second exposures. Supernova are generally visible for between a few days and a few months.

TL;DR. He is the first human in history to witness the first hour of a supernova being created. Astronomers had theorized what it would looked like and his photographs confirm it and his notification allowed astronomers to study the supernova early hours in depth as never before.

I'm confused by this. There have been several supernovas throughout history that were bright enough to be seen without instruments, including some ones in 1006 and 1054 that were quite a bit brighter than Venus, and ones in 1572 and 1604 that were brighter than Jupiter.

How do we know no human happened to be watching during the first hour of one of these?

"Observed" ... many people have seen the moon, but few people have "observed" it. ie: gathered evidence, etc.

I may see a fly across the room, but I'm not really "observing" it in any meaningful way unless I'm prepared, with proper sensors, cameras, etc. recording what's going on so that other people can learn from it.

Your question is fallacious. The point is he is the first known person to have witnessed it in known history, the odds of such were calculated to be 1 in 10 million.

That style of NYT headline writing is obnoxious.

Social capital Is a blessing and a curse at the same time..

But I agree, beautiful story!