How many supernova explode every year?

badastronomy.beehiiv.com

368 points by rbanffy 14 days ago


rookderby - 11 days ago

First off, dont look at the outer wilds discussion on here, just play the game. Second - they didnt say how many letters we need to encode all of the observable supernova in a given year! So 100 billion galaxies, 1 per year per galaxy, we have around 1 billion to encode. Sorry two edits this moring, first one was right. due to math without coffee. 1e9/26^6 is about 3, 1e9/26^7 is less than one. So we might see 'SN2050aaaaaah'!

tialaramex - 11 days ago

That's one of my favourite hints in Outer Wilds. You will see a Supernova. Not with a fancy telescope, it's visible to the naked eye, and if you watch the sky you'll see another soon enough. You can see this right at the start, and unlike the random direction of the probe launch you don't need any game lore to, if you're smart enough, put two and two together.

kakuri - 11 days ago

I really feel like this article should also mention the rate of formation of new stars. According to [1] Universe Magazine the James Webb telescope has revealed that more than 3,000 stars are formed every second.

[1] https://universemagazine.com/en/james-webb-comes-closer-to-r...

jxf - 11 days ago

I think this says less about supernovas and a lot more about how staggeringly, incomprehensibly vast the observable universe it.

ben_w - 11 days ago

Hmm…

So that's cool, but now I'm thinking: the distant galaxies are redshifted and time-dilated in equal proportion, and also more densly packed because the universe was smaller in the past, so I expect the actual rate of supernovas to be significantly smaller than simply multiplying 1/century/galaxy by 1e11 galaxies.

Edit: also I don't know if rate of supernovas changes over history thanks to different steller environments giving the population-1/2/3 generations of stars…

dr_dshiv - 11 days ago

The most stars a person can see with the naked eye? About 8000.

And, less than half that, actually — since we can’t see the other side of the hemisphere

herendin2 - 11 days ago

If I got the math right, then about 1 in every 32,000 stars in the universe goes supernova each year. That's scary. But I think I'm getting the math very wrong.

edit: I guess my error might be related to confusing a probability factor with the number of incidents in a period.

edit: The right answer is probably up to 1 in every 10bn stars go supernovae in the universe each year (or 1 in 10bn die and a fraction are supernovae). Thanks: yzydserd and zild3d

belter - 11 days ago

The SuperNova Early Warning System (SNEWS): https://snews2.org/

brings together the fantastic [1] Super-Kamiokande, the [2] IceCube, and other global detectors, to provide early warning of Supernovas.

You can subscribe... https://snews2.org//alert-signup/

[1] https://en.wikipedia.org/wiki/Super-Kamiokande

[2] https://en.wikipedia.org/wiki/IceCube_Neutrino_Observatory

rwky - 10 days ago

This reminds me of a few years ago when I was doing my MSc our group was learning how to work one of the remote telescopes and we were asked to point it at the brightest object found by Gaia that week and it turned out to be a supernova. Very cool for your first observation using a remote telescope! If anyone wants to see it here it is https://ibb.co/Kzqbfq30

And here is the Gaia data http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia23bqb/

thih9 - 11 days ago

> [Supernova discovery statistics for 2021] says there were 21,081 supernovae seen in 2021

> When the Vera Rubin survey telescope goes online, it’s expected to see hundreds of thousands of supernovae per year by itself.

drbig - 11 days ago

The universe is vast and full of nothing...

Which in case of explodey stars is a very good thing indeed!

selectnull - 11 days ago

Astronomers will find out that naming is hard once they need to name 119741st supernova.

darthrupert - 14 days ago

The whole things seems like such a massive living system that I cannot help guessing that what we think of as universe is just a somewhat large single creature.

ur-whale - 11 days ago

Spoiler alert:

> THIRTY SUPERNOVAE PER SECOND, over the entire observable Universe.

state_less - 11 days ago

Reminds me of the last lines of the diamond sutra.

> So you should view this fleeting world—

A star at dawn, a bubble in a stream,

A flash of lightning in a summer cloud,

A flickering lamp, a phantom, and a dream.

jl6 - 11 days ago

Ah, the good old column naming convention from MS Excel. Now there’s an amazing creation that occasionally explodes catastrophically.

didgetmaster - 11 days ago

Two questions come to mind.

1) When was the last supernova observed in our own galaxy?

2) How close would one have to be to be observed with the naked eye?

coryfklein - 11 days ago

Near the top he shows two photos of the Cartwheel galaxy, one from 2014 and one from 2021 with the caption:

> Can you spot Supernova 2021 axdf?

Are you supposed to be able to spot the supernova?

All I've noticed is a couple of small stars that disappear in the latter photo, but this mostly seems to be because it's more blurry.

deadbabe - 11 days ago

Can the thread title be rewritten to be less obnoxious? “How many supernova explode every year?” is fine. This isn’t Reddit. Thread titles should not imply some kind of personality or use cliche meme speak. The all caps is definitely an abomination.

lifeisstillgood - 11 days ago

No wonder the Millennium Falcon takes so longer to calculate its jump to hyperspace.

Tens of thousands a year is one an hour!

There are so many supernovae you really could bounce too close to one and that would end your trip real quick

croes - 11 days ago

Was surprised by the „Und so weiter“ in the text.

nashashmi - 11 days ago

And just when we add that variable to our formula we can finally teleport ourselves on to hyperspace.

jampekka - 11 days ago

I couldn't spot the supernova and there's no answer to where it is. :'(

SwtCyber - 11 days ago

Absolutely mind-blowing how much our ability to observe the universe has exploded

croisillon - 11 days ago

maybe some Supernova-Names get deleted, like SN2021acab?

fswd - 10 days ago

I've seen two super nova in my life time. once in 2008 and another in 2012

28374654 - 11 days ago

[flagged]

henryway - 11 days ago

Sounds like he was caught beneath landslide, in a champagne supernova… a champagne supernova in the sky

roenxi - 11 days ago

We're dealing with the sum total of everything, if the true nature of things is that there are a finite number of supernovas I'd be surprised. The real shock is how small the number of supernovas is and how young everything seems to be in the known universe (the age of the observed universe is estimated at maybe double digit billion years).

These are tiny numbers given that we're quite possibly dealing with infinity in both time and space. I judge it one of the stronger arguments in favour of the universe being constructed (or, more likely, there is a lot out there we can't see). If god built a universe numbers like 1 supernova a century make some sense for artistic value.